GUIDE 2005 Z 9181 Trussteel Design Manual 2012

User Manual: Z 9181

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The World Leader in

Cold-Formed Steel Trusses

Truss Design Manual

a division of ITW Building Components Group

888.565.9181 • www.TrusSteel.com

a division of ITW Building Components Group

Truss Design Manual

TRUSS DESIGN MANUAL

1 OVERVIEW

1.01 Introduction

1.02 Specifiers & Designers

1.03 Contractor & Installer

1.04 Truss Components & Code Recognition

1.05 Framing & Connections

1.06 Authorized TrusSteel Fabricators

1.07 Education & CES

1.08 Notes Page

2 APPLICATIONS

2.01 Applications

2.02 Projects

3 SPECIFYING / DESIGNING

3.01 Overview

3.02 Building Codes & Design Standards

3.03 Information Required for Truss Design

3.05 TrusSteel System

3.07 Wind Loading

3.10 Snow Loading

3.11 Seismic Loading

3.13 Sound Control

3.14 Sustainability & LEED

3.15 Fire Resistance & UL

3.16 Trusses as Building Components

3.17 Roof Truss Systems - Framing

3.22 Roof Truss Systems - Sample Spans

3.23 Floor Truss Systems

3.26 Guide Specifications

This Design Manual is intended as a guide to building professionals for suggested uses of TrusSteel trusses. The building code of jurisdiction and a truss design

professional should be consulted before incorporating information from this publication into any plan or structure.

ITW Building Components Group, Inc., nor any of its divisions or companies, does not warrant the recommendations and information contained herein as proper

under all conditions and expressly disclaims any responsibility for damages arising from the use, application or reliance on the recommendations contained herein.

4 ENGINEERING / SHOP DRAWINGS

4.01 Engineering

4.03 Shop Drawings

4.04 Notes Page

5 DETAILS / CONNECTIONS

5.01 Overview

5.03 Standard Details

5.04 Truss-to-Truss Connections

5.06 Gable Outlooker Connections

5.07 Truss-to-Bearing Connections

5.13 Piggyback and Valley Truss Connections

6 TRUSS FABRICATION / QUALITY

6.01 Overview

7 INSTALLATION / BRACING

7.01 Site Conditions & Safety

7.02 Handling & Storage

7.03 Lifting & Staging

7.04 Bracing

7.05 Rafting

8 REFERENCES / RESOURCES

8.01 Industry Resources

8.02 Glossary

8.07 Weights of Materials

TABLE OF CONTENTS

1206

NOTES

OVERVIEW

This Manual is intended for quick reference only. Drawings and illustrations shown are samples only and are not intended for detailing

or construction. Please refer to the TrusSteel Standard Details for technical information on connection design, product use and safety.

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1.01

Unmatched strength and stiffness in a

cold-formed steel truss.

TrusSteel is the most accepted, most specified cold-

formed steel (CFS) truss system on the market today. No

other building component combines strength, stiffness, fire

resistance, insect resistance and design flexibility so well.

The unique, patented truss chord shape and Double-

ShearTM fasteners, combined with multiple types of web

shapes, make TrusSteel CFS trusses, pound-for-pound, the

strongest and stiffest cold-formed steel trusses on the

market. Not surprisingly, these same characteristics

combine to create a light, economical steel building

component having exceptional load-span capabilities, with

clear spans in excess of 80 ft.

Supported by powerful Alpine steelVIEWTM design and

analysis software, TrusSteel CFS trusses provide reliable,

economical structural solutions for almost every roof or floor

application.

The Most Trusted Name in CFS Trusses

Alpine Engineered Products, Inc. was a driving

force in the creation of the wood truss industry

over forty years ago. Since that beginning, the

industry has consistently recognized Alpine as

engineering and innovation leaders. Now, as a

part of the ITW Building Components Group, Inc.

Alpine provides the same leadership in the

founding and development of the pre-engineered

CFS truss industry.

The TrusSteel Division has decades of combined

expertise in the truss and CFS building products

industry. The TrusSteel product line combines

over forty years of truss engineering and

software knowledge with cutting-edge

rollforming technology and the proven quality of

in-house truss fabrication. As a result, more

TrusSteel trusses are installed each year than

any other proprietary CFS truss system.

TrusSteel provides ongoing leadership to the

truss industry through hands-on participation in

key organizations such as the Cold-Formed Steel

Engineers Institute (formerly LGSEA), the

American Iron and Steel Institute, the CFS

Council of the SBCA, the AISI Committee on

Framing Standards (COFS), and the Center for

Cold-Formed Steel Structures.

TrusSteel is actively involved in programs with

the International Code Council and Underwriters

Laboratories.

Every TrusSteel truss is designed using the

industry-leading Alpine steelVIEW software.

steelVIEW is the most accurate truss design

software in the industry for a number of reasons,

including:

• True multi-node modeling, not the estimated

node modeling used by other CFS truss design

software packages.

• Multiple load case analysis applied to each

truss, including gravity, wind, seismic and

unbalanced conditions.

• Analysis methodologies derived from the most

extensive full-scale testing program in the

industry, utilizing the AISI Specification for the

Design of Cold-Formed Steel Structural

Members.

Authorized TrusSteel Fabricators, operating

the steelVIEW software in-house and

supported by TrusSteel engineering

resources, provide solutions for the most

complex truss systems.

American

Iron and Steel

Institute

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1.02

OVERVIEW

Outstanding design flexibility

TrusSteel CFS trusses provide the same span

capabilities and design flexibilities as wood

trusses. The pre-engineered system allows much

greater design flexibility than steel “C” truss

framing. As a result, you can design in familiar

roof lines - pitched or flat, with hips, gables,

gambrels, monos, mansards, cantilevers,

overhangs, scissors and floor trusses. This

design flexibility makes TrusSteel trusses ideal

for almost any building type: new construction,

retrofit, commercial, institutional, military,

educational, industrial and municipal structures.

Easy to specify and design

There is a wealth of information available to help

you specify and design with TrusSteel. A guide

specification in CSI format, and standard details

in DXF and DWG formats, can assure that your

specs and construction documents are accurate

and complete. UL, ICC Legacy report (NER) and

Florida Product Approval are available to assist

you in making design decisions and in working

with code officials. Local TrusSteel fabricators

can aid you in making informed decisions about

project designs and costs.

Responsible products

TrusSteel CFS trusses contribute to a safe built

environment. They do not emit moisture or fumes

during their life cycle. They are resistant to insect

attack, and do not provide a medium for the

growth of mold. And most of the steel used for

CFS framing is recycled steel.

Recognized fire resistance

Noncombustible TrusSteel trusses provide

integral, recognized fire resistance that does not

fade with time. See the following pages for a list

of TrusSteel’s useful, cost-saving UL-listed roof

and floor assemblies.

Assured structural performance

With over forty years of experience in the truss

industry, you can be assured that TrusSteel

understands the structural performance of

trusses. The powerful steelVIEWTM truss design

software analyzes each truss individually using

the latest industry standards, guided by the new

ANSI/AISI/COFS -Standard for Cold-Formed Steel

Framing -Truss Design. Finally, each truss design

is reviewed and sealed by a TrusSteel

Professional Engineer.

Quality trusses

TrusSteel CFS trusses are built in a shop

environment with experienced fabrication

personnel. TrusSteel endorses industry truss

shop quality control standards as developed by

the Cold-Formed Steel Council.

Economical system

Since TrusSteel CFS trusses are the stiffest

trusses in the industry, less permanent bracing is

typically required in the truss system. This

feature, combined with excellent performance at

4 ft. on-center spacings or greater, can reduce

the cost of the installed truss system through

reduced labor costs, materials and project

duration. Property insurance premium discounts

may provide long-term savings.

Nationwide availability

TrusSteel supports the largest network of

independent CFS truss fabricators in the

industry. This nationwide network assures that

TrusSteel trusses are available for your projects

in every region of the United States.

Design Flexibility

Specifiers & Designers

The Inn at Biltmore Estate, Asheville, NC

Project Phoenix-rebuilding the Pentagon after 9-11

PGA Headquarters, FL

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1.03

Safer to Handle

Unique features of TrusSteel trusses make them

safe to handle and install. Stiffer trusses add

handling control and reduce the danger of

buckling during lifting and placement. The rolled

edges of the chords and webs help protect

workers from cuts.

Easier to Install

TrusSteel trusses can be as light as one-half the

weight of similar wood or “C” stud steel trusses.

Unlike some other CFS trusses, laterally stiff

TrusSteel trusses resist folding or “butterflying”.

And TrusSteel trusses work exceptionally well in

rafted installations.

No Special Tools Required

The tools you are now using to install CFS

framing are all you need to install TrusSteel

trusses. A full line of TrusSteel construction

hardware allows you to make connections with

standard screws. Installation details and

construction hardware are available from your

Authorized TrusSteel Fabricator.

Reduced Callbacks

TrusSteel trusses reduce callbacks because they

start straighter and remain straighter than many

other types of trusses. And the dimensional

stability of steel reduces drywall fastener pops.

Save Time, Effort and Money

TrusSteel trusses streamline the building cycle

and save money.

• Timely quotations from local TrusSteel

Authorized Fabricators provide

competitive prices and define project

costs up front.

• Sealed engineering drawings and code-

compliant components expedite

submittals.

• Quicker turn-arounds for revisions.

• Delivered to the site ready to install, shop-

built trusses save days of labor.

• Faster truss installation with accurate

layouts, extensive details, and a full line of

installation hardware.

• Easier site inspections with

comprehensive shop drawings and

clearly identified components.

Delivered Quality

Roof lines plane accurately, eaves and soffits

align properly, and interior ceiling lines are flat

and true. High-quality TrusSteel trusses help you

achieve your quality goals.

Delivered Value

From bidding to punch list, TrusSteel delivers

value to your project through increased safety,

quality, efficiency and cost-effectiveness.

Contractor-Friendly Installation

Truss Rafting

What is Rafting?

Truss rafting is a framing technique where

completed trusses, designed to be rafted, are

assembled into an entire roof section on the

ground and then lifted as an assembly onto the

building structure. The assembly can consist of

just the trusses, or the trusses plus purlins, roof

deck and final roofing which is all installed on the

ground before the assembly is lifted into place.

Employing a rafting technique can save time,

increase safety and reduce insurance costs on

many projects.

Why Raft With TrusSteel?

The exceptional strength-to-weight characteristics

and lateral stability of the TrusSteel trusses make

them the ideal truss for use in a rafting process.

These characteristics allow an average-sized

crane to lift the completed truss assembly into

position. The stiffness and stability of the

TrusSteel trusses create an assembly that will

survive a lift without introducing significant

additional bracing.

Contractor & Installer

OVERVIEW

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1.04

Unique Chord Sections

The symmetrical shape of TrusSteel’s patented

U-shaped chord sections provides nearly equal

chord member moment capacity in both in-plane

directions. The TrusSteel chord members have

superior bending strength in out-of-plane

directions. These characteristics combine to

create an efficient truss that is exceptionally

strong and stiff. The recent addition of special

chord sections for short span / low load

conditions and for long span / high low

conditions improves the value engineering of the

entire system.

Webs

TrusSteel utilizes both commercial grade closed-

tube webs and proprietary roll-formed z-webs to

deliver the most cost effective roof system. Both

products have unique “double symmetric”

properties which contributes to the strength,

stiffness and stability of the truss as well as

reducing lateral bracing.

TrusSteel members are designed and built in compliance with ASTM A370, ASTM A653, ASTM A500,

ANSI Standards, and voluntary standards as described in our own reports from Underwriters

Laboratories (UL) and ICC Legacy reports (NER and Florida Product Approval). Visit our web site to

download the complete reports.

Patented Fasteners

TrusSteel is the only CFS truss system in the

industry using Double-ShearTM fastener

technology. This patented technology provides a

rigid, bolt-like connection at all chord/web

intersections and is specially designed to resist

movement and back-out. Color-coded, marked

fasteners create the most dependable, easily

inspected connection available for CFS

materials.

Structural Connections

TrusSteel delivers a full line of truss-to-truss and

truss-to-bearing connectors that provide

consistent quality and structural values.

The industry’s most extensive library of Standard

Details describing our connections, connectors and

section properties is available in various CAD formats

on CD or from www.TrusSteel.com.

UL Listings TrusSteel products qualify for hourly ratings as shown below.

Assemblies

Truss Components

Code Recognition

Truss Components & Code Recognition

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1.05

Framing & Connections

TrusSteel Connectors

An extensive set of TrusSteel connectors and

application details allows a designer to create a

complete truss framing system, whatever the

roof type, supporting conditions or other framing

materials. All TrusSteel connectors are load-

rated connectors.

Refer to Section 5 of this manual for the

engineering values of our full line of connectors

(simplified examples are shown here). TrusSteel

Standard Details are available for each

connection application. These Details include

load data as well as installation requirements.

Standard Details are available in CAD formats

from www.TrusSteel.com and are also contained

on the electronic version of this manual.

SteelDraw Truss Shop Drawings with:

• All trusses marked and coordinated to layout

• All truss members clearly identified

• Complete general notes

• Fully dimensioned truss profile with bearing elevations,

fastener quantities, pitch marks, web bracing locations and more

• Truss reactions and bearing widths

• Job-specific loads

Layout Drawings with:

• Truss marks

• Key bearing and framing dimensions

• Truss spacings

• Connection and bracing details

Standard Details

Truss ShopDrawTM and LayoutTM Information

OVERVIEW

HANGER DETAILS UPLIFT ATTACHMENT TO STEEL UPLIFT ATTACHMENT TO STEEL

UPLIFT ATTACHMENT TO CONCRETE SPRINKLER PIPE HANGER SPRINKLER PIPE HANGER

Bottom chord bearing truss

to girder truss

Bottom chord bearing truss

to steel beam connection

Bottom chord bearing truss to

CFS track connection

Bottom chord bearing truss to

concrete bearing

Bottom chord sprinkler pipe hanger

using Sammys x-Press 35 (XP 35)

Truss top chord hanger

detail

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1.06

OVERVIEW

What services can an Authorized

Fabricator provide?

Knowledge. TrusSteel Authorized Fabricators are

truss experts. They can answer questions about

truss applications and installations as well as

questions about pricing and delivery. Do you

have questions about truss layouts, spans,

spacings, profiles, systems, connections,

bracing, overhangs, mechanical chases...and

more? Call your local Authorized Fabricator. They

can save you money up front in your design

development or structural design process.

Engineering. All TrusSteel trusses are

engineered trusses. An Authorized Fabricator can

provide not just building components, but can

also provide individually-engineered and sealed

trusses. A staff of over fifty engineers, covering

every state in the USA, reviews and seals over

4,500,000 truss designs each year.

TrusSteel provides steelVIEWTM software to all

Authorized Fabricators. This powerful proprietary

software package includes 3-D modeling and

truss layout, truss engineering and bidding

modules. By-products of these key elements are

industry-best truss layouts, shop drawings and

cutting sheets.

Quality trusses. Each Authorized Fabricator

builds TrusSteel trusses in a plant environment to

ensure the highest quality components. Trusses

are built according to engineered shop drawings

and highly accurate cutting/assembling

drawings created by the steelVIEW software.

TrusSteel trusses are built with patented Double-

ShearTM fasteners and internal connectors to

assure consistently accurate trusses.

How can I find local Authorized

Fabricators?

You can find a list of Authorized Fabricators on

the TrusSteel Web site at www.TrusSteel.com. Or,

you can call the TrusSteel information line at

888-565-9181. Wherever your project is located,

you can probably find at least two Authorized

Fabricators to provide competitive quotes on

your project.

Additional Services

Structural Services. Through their affiliation

with strategic partner BBD Engineering & Design

Firm, LLC (www.bbdengineering.com), a fee-

based, full-service consulting engineering firm,

TrusSteel Authorized Fabricators can provide full

framing system design services (including the

design of special connections, bracing, purlins,

decks - even entire building framing systems).

Authorized TrusSteel Fabricators

Who is a TrusSteel Authorized

Fabricator?

A TrusSteel Authorized Fabricator is an

independently-owned and operated local

truss fabrication shop. Each Fabricator

markets and services truss projects in their own

region, backed by over 40 continuous years of

Alpine truss experience. Taken together, the nationwide

network of TrusSteel Authorized Fabricators forms a vast repository of truss and framing

knowledge at your disposal.

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1.07

Attention:

Project Architects

and Engineers

The TrusSteel Division has several

educational presentations that we can

make in your office or at the local

chapter of your professional

organization.

The “Cold-Formed Steel Trusses 101”

and “Bracing for Steel Trusses”

presentations are accredited by the

American Institute of Architects under

their Continuing Education System. AIA

members who participate will receive

one LU Hour of credit, and TrusSteel will

file Form B with the AIA. All other

participants will receive a Certificate of

Completion.

Target Audiences

Architects, engineers, specifiers and

other design professionals in the

building market; can be presented to

any size audience.

AV Needed

Electrical power and a screen for

PowerPoint (CES facilitator will provide

the laptop computer, video projector and

samples).

Other non-accredited presentations are

available, suitable for various venues.

Contact your TrusSteel Regional

Manager for details.

Facilitator Qualifications

TrusSteel facilitators have extensive

experience in the truss and building

industries and are well versed in truss

design and installation.

Length: One Hour

Credits: One LU Hour

HSW: Yes

Cost: None

Description

This presentation includes a brief history and

overview of the various types of cold-formed

steel (CFS) truss systems on the market, their

physical and structural characteristics and

performance, common system applications and

limitations, and how to specify these systems.

Length: One Hour

Credits: One LU Hour

HSW: Yes

Cost: None

Description

This presentation includes an overview of the

various types of cold-formed steel (CFS) truss

systems on the market, common loading

situations, structural construction bracing needs

and how to specify the bracing for these

systems.

Educational & CES

Learning Objectives

At the end of this program, participants will be

able to:

• Identify the different types of CFS truss

systems,

• Understand the product capabilities and

limitations of various CFS truss systems,

• Specify a CFS truss system.

How Taught

Using a PowerPoint presentation and physical

samples, the CES facilitator presents information

on the nature and types of CFS truss systems,

including basic terminology and applications.

Physical samples are used to demonstrate truss

terminology.

Cold-Formed Steel Trusses 101

Bracing for Steel Trusses

Learning Objectives

At the end of this program, participants will be

able to:

• Identify the different types of CFS truss

systems,

• Understand common load conditions,

• Specify the bracing for a CFS truss

system.

How Taught

Using PowerPoint and physical samples, the CES

facilitator presents information on the nature and

types of CFS truss systems, including basic

terminology and applications. Physical samples

are used to demonstrate truss terminology.

OVERVIEW

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1.08

OVERVIEW

Notes

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2.01

Institutional – Schools – Universities – Churches – Museums – Healthcare – Clinics – Hospitals – Assisted Living Centers – Retirement

Centers – Municipal – Community Centers – Town Halls – Hospitality – Hotels – Motels – Commercial – Malls – Banks – Truck Stops

Telecommunications – Shopping Centers – Restaurants – Historical Renovation – Industrial – Storage – Roof Refit - Condominiums

Multi-Family – Single-Family – Recreation – Ball Parks – Gaming – Government/Military – Barracks – Depots – Offices

TrusSteel Cold-Formed Steel (CFS) trusses

are now in service within literally thousands

of buildings, in dozens of building

applications.This guide shares only a small

fraction of the total uses of TrusSteel. You

can view additional information on these

case studies and other studies on the

TrusSteel web site: www.TrusSteel.com.

TrusSteel trusses can be used to create

roofs and floors of all types (gables, hips,

monos, gambrels, etc.). They can be used in

many special applications, including:

• Re-roofs (over existing structures)

• Equipment screens

• Porte cocheres

• Ag structures

• Flat roofs

• Canopies

• Mansards

• Shelters

• Frames

Your imagination is the only limit

APPLICATIONS

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2.02

APPLICATIONS

Military

Reconstruction of the Pentagon began immediately after 9-11, with

all parties committed to completing the restoration within 12 months.

The Pentagon reopened on-time, on-budget, on the very hard work

and cooperation of everyone involved.

The Pentagon

Project Phoenix

Arlington, VA

Davis-Monthan AFB

New Dormitories

Tucson, AZ

Seven entire roofs were built on the ground and lifted into place, complete

with trusses, bracing, decking and mechanicals. This installation technique

is called rafting. See Section 7 for more information.

Estimated time savings on the project: two weeks.

Fort Wainwright

New Lodging Facilities

Fairbanks, AK

Rafting (assembling entire sections of the roof system on the ground

and lifting into place) allowed this contractor to meet deadlines set by

the short building season in Alaska. Structural design of the truss

system, lifting bracing, permanent bracing and all connections was

done by TrusSteel.

APPLICATIONS

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2.03

Hospitality / Eldercare

Over 35,000 SF of TrusSteel trusses top the new Inn on Biltmore

Estate. Located on a national historic site, quality and ease of

installation were of paramount importance to the owner.

Unusual framing situations, including radial and conical roof areas,

provided challenges met by the truss fabricator and TrusSteel

engineering team.

The Inn on Biltmore Estate

Luxury Hotel

Asheville,NC

Design Flexibility

The pre-engineered TrusSteel system allows much greater design

flexibility than steel “C” truss framing. As a result, you can design in

familiar roof lines - pitched or flat, with hips, gables, gambrels,

monos, mansards, cantilevers, overhangs, scissors - as well as floor

trusses. This design flexibility makes TrusSteel ideal for almost any

building type.

The Garlands

Assisted-Living Community

Barrington, IL

Over 150,000 SF of TrusSteel trusses helped to create the “French

Country” style of this campus. One of the many TrusSteel UL Listed

assemblies met the architect’s and owner’s requirements for fire

protection.

Noncombustible TrusSteel trusses provide integral, recognized fire

resistance that does not fade with time. Useful, cost-saving UL

Listed roof and floor assemblies can help you meet the needs of

demanding building types, owners and codes. For more information

on UL Listed assemblies, see Section 3 of this Manual.

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2.04

APPLICATIONS

Municipal / Institutional

The design of this fire station required long, clear spans and

noncombustible framing. The truck bay areas were covered with 85-foot

clear span TrusSteel trusses. For ease of shipment,

these trusses were shop fabricated in two halves that

were then connected together in the field by the

installer.

Golden City Station

Fire Station

Louisville, KY

PGA Headquarters

Historical Center

Port St. Lucie, FL

The new showpiece of the Professional Golfers

Association headquarters campus is the PGA Historical

Center. TrusSteel trusses were selected for their high

quality and overall economy of installation.

Coral Baptist Church

New Church Complex

Coral Springs, FL

The truss systems for the many roofs over this new worship,

education and fellowship complex contained just about every type

of truss under the sun. There were piggybacked trusses, flats,

drags, hips, commons, monos and radials - with about every

bearing condition imaginable, including heavy steel, CFS steel, bar

joists and masonry. Because of the design flexibility of TrusSteel

CFS trusses, they interfaced well with all these types of framing

systems.

APPLICATIONS

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2.05

Industrial / Educational / Residential

Collaboration between engineers at Freightliner, TrusSteel and the local

truss fabricator resulted in a state-of-the-art design framed completely

from TrusSteel products.

Freightliner Research Facility

Wind Tunnel

Swan Island, OR

Alleghany Highlands Schools

Elementary and Middle Schools

Lowmoor, VA

This campus of new elementary and middle schools included

over 112,000 SF of TrusSteel trusses. TrusSteel cold-formed

steel (CFS) trusses offer the features of non-combustibility,

UL-Listed assemblies and recycled content demanded on many

school projects.

Schnee Residence

Scottsdale, AZ

Over 12,000 SF of TrusSteel trusses shelter this new home in the

desert. Fifty-foot trusses framed in a radial pattern created large,

open living areas.

TrusSteel CFS trusses are among the lightest and strongest steel

framing made. They are an excellent alternative to heavier steel

framing and trusses, such as “C” stud trusses or stick framing.

Because of their superior lateral stiffness and high strength-to-

weight ratio, TrusSteel common trusses, in short spans, may be

lifted and installed without the use of a crane. This can provide a

significant benefit on small projects or structures built in areas

with limited access.

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3.01

SPECIFYING / DESIGNING

Specifications & Design Overview

Pre-Engineered Trusses

Cold-Formed Steel (CFS) trusses should be

specified as “pre-engineered” trusses. The term

"pre-engineered" reflects the concept of a

desired outcome, where the individual trusses

have been fully analyzed and engineered to meet

all specified load conditions. Individual truss

designs should be sealed by a Professional

Engineer who is registered in the state where the

project is located.

Pre-Fabricated Trusses

CFS trusses should also be specified as “pre-

fabricated cold-formed steel (CFS) trusses”.

Trusses should be fabricated in a shop

environment with experienced fabrication

personnel. Trusses that are fabricated at the job

site should not be allowed. TrusSteel endorses

industry truss shop quality control standards as

developed by the SBCA’s Cold-Formed Steel

Council.

The terminology “cold-formed steel” is replacing

the old terminology of “light gauge steel” for

several reasons. In the code standards for these

products (AISI, COFS, ICC, etc.), these products

are now referred to as cold-formed steel. In

addition, the gauge system of referencing

material thicknesses is becoming obsolete and

has been replaced with mil thickness

designations.

Industry Standards

The specifier should assure that all applicable

industry standards are referenced within the

project specification. All applicable loads and

load conditions, as well as all other performance

criteria, applicable codes, building use and

geometry, etc. should be clearly defined within

the specifications and project design drawings.

For a further discussion on required information,

please see “Information Required for Truss

Design”.

Specifying CFS Trusses

Design and Review Process

Requirements

Due to its importance in the overall success of a

project, it is worth repeating that the Building

Designer must clearly state, in the plans and

specifications, all specific requirements for the

trusses. This clear and thorough communication

of performance criteria will help truss suppliers,

general contractors and truss installers provide

more accurate pricing, preliminary designs, and

ultimately a better product on the project.

Truss Design

Project plans and specifications will eventually

be sent for pricing to companies involved in the

manufacture of CFS trusses. After a truss

manufacturer is awarded the project, the actual

design of the truss system will begin. The truss

manufacturer will use the plans and

specifications to create an economical truss

framing package.

Truss Package Submittal

Once the truss designs have been completed and

sealed by a professional engineer, the designs

will be submitted to the Building Designer for

review and approval. If the Building Designer is

satisfied with the truss submittal, then the truss

manufacturer will begin fabricating the trusses. If

the Building Designer is not satisfied, the truss

submittal will be rejected and returned to the

truss manufacturer along with precise

instructions on corrective action. The truss

manufacturer will make the necessary

corrections and then resubmit the trusses to the

Building Designer. This process will continue

until the Building Designer approves the truss

submittal package.

Approval, Fabrication and Delivery

Once the Building Designer approves the truss

submittal package, the truss manufacturer will

begin the fabrication of the trusses. After

fabrication, the trusses will be delivered to the

jobsite, ready to be installed on the building.

As a tool for the specifier, a complete Guide

Specification for TrusSteel, written in

standard three-part format, is available on

the CD version of this manual.

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3.02

SPECIFYING / DESIGNING

Applicable Building Code

For many years, the vast majority of building

construction within the USA was governed by

one of three model building codes: UBC, SBC or

BOCA. In recent years, these three codes have

merged and been reborn as the International

Building Code (IBC). The IBC, as developed by the

International Code Council (ICC), has been

adopted by municipalities and will be the

applicable model code for the vast majority of

construction within the USA.

The provisions of the applicable building code

will provide important factors in the design of any

given project. For this reason, one of the first

steps a Building Designer should undertake in

the design of any building is the precise

identification of the applicable code. This

concept may seem too obvious, but there can be

different versions of the same building code (e.g.

different publication dates) in use. There are also

instances when a city or an entire state may

decide to publish its own building code.

Requirements for Design Completion

Once the Building Designer has ascertained the

applicable code, they can discover the minimum

requirements for design completion that the

municipality has set forth for its jurisdiction. Most

municipalities state that they require a 100%

complete design at the time of permitting.

Selecting the Structural System

One of the most important decisions made

during building design will be the selection of the

structural system. Once a system is selected, the

Building Designer will go to the applicable code

and find the provisions that will control the

design of the structural elements. For CFS

systems, the “Steel” chapter of the code will

present these provisions.

The applicable building code will either

completely outline the design procedures for a

particular material or it will reference the

required design standard. If a design standard is

referenced, this will be clearly stated in the

building code and the Building Designer can

proceed to the “Referenced Standards” chapter

to locate the proper design standard.

Design Standards

Model building codes contain provisions for the

design of almost any type of building using many

types of materials, including CFS. The

International Building Code (IBC) will determine

the design provisions for construction with CFS

in two different ways. The first way is to provide

explicit provisions that are published within the

Code. The second way is to adopt existing

standards by reference.

For the IBC to adopt a standard by reference, that

standard must be developed according to

guidelines created by the American National

Standards Institute (ANSI). As with any building

material, CFS members are designed according

to standards developed by industry organizations

that are intimately familiar with the design of CFS

members. In the CFS truss industry, the

American Iron and Steel Institute (AISI) is the

organization that is ANSI-approved to develop

standards. Within the AISI, there are two ANSI

standards writing committees: the Committee on

Specifications (AISI/COS) and the Committee on

Framing Standards (AISI/COFS).

The AISI/COS has developed the primary

standard for CFS design that is in use today: the

North American Specification for the Design of

Cold-Formed Steel Structural Members (AISI-

S100). This standard outlines what types of steel

shall be considered as CFS and how CFS

members shall be designed when subjected to

moment, shear and axial forces. The standards

developed by the AISI/COFS use this document

as their baseline for design procedures and

expand upon specific issues of the given framing

type.

Building Codes & Design Standards

AISI / COFS Standards

The AISI/COFS has developed eight

standards that are in use today:

•General Provisions

(AISI-S200)

•Code of Standard Practice

(AISI-S202)

•Wall Stud Design

(AISI-S211)

•Header Design

(AISI-S212)

•Lateral Design

(AISI-S213)

•Truss Design

(AISI-S214)

•Prescriptive Method for One and

Two-Family Dwelling

(AISI-S230)

Of the eight AISI standards listed

above, General Provisions, Truss

Design and the Code of Standard

Priactice documents affect the design

and fabrication of CFS trusses. These

standards are subject to periodic

revision. Please check the AISI Web

site for the most current revisions.

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3.03

SPECIFYING / DESIGNING

Information Required for Truss Design

Building Use

Building regulations differ for various types of

use and occupancy. Specific classifications of

use are: single family residential, multi-family

residential, offices, retail, manufacturing,

churches, institutions (long-term care, nursing

homes, schools, hospitals, jails, etc.) or

agricultural (non-human occupancy). There are

also fire protection requirements for buildings

that may require the CFS members and

assemblies to perform in specific manners.

At times, the CFS truss system may be required

to perform in an atmosphere that may be

corrosive to CFS members. It is important to

properly specify the level of protection that will

be required to keep the underlying steel safe

from damage by this atmosphere.

Applicable Building Code

Clearly identify the Applicable Building Code for

the specific site location (also called the Building

Code of Jurisdiction).

Geometry of the Structure

Furnish span (out-to-out of bearings, plus

cantilevers, if any), slope, overhang conditions,

etc. that form the profiles or external geometry of

the trusses. Truss web configurations need not

be furnished, as they are determined by the

overall truss design.

Truss Bearings

Specify all exterior and interior points of bearing,

showing location by dimensions, size, and

elevation above ground or benchmarks. It is

important to specify the type of bearing material

to be used to properly design connections to the

bearing. Required information could include

grade of steel, grade of wood, strength of

concrete, etc.

Truss Spacings

Give desired center-to-center spacings of

trusses.

Truss Restraint

When designing trusses, it is important that the

truss designer know how the truss chords will be

restrained. The two most common methods of

restraint are structural sheathing and purlins.

In the structural sheathing method, sheathing -

most commonly plywood, oriented strand board

(OSB), and metal deck (such as B-deck) - is

applied directly to the truss chords. The design

and connection of these decks to the trusses is

the responsibility of the building designer.

In the purlin method, CFS members used as

purlins are attached directly to the truss chord to

properly support the truss chord laterally. CFS

hat channels or Z shaped members are

commonly used as purlins. This method is

typically used when the sheathing material is not

capable of spanning the distance between

trusses. The design and connection of the purlin

members is the responsibility of the building

designer.

Truss manufacturers need certain specific information on every project

in order to design and fabricate trusses. As a building designer, specifier

or installer, you can help expedite your order and assure proper fit by

providing the following information to the truss manufacturer.

Support of Mechanical Equipment

Trusses under mechanical units must be

specifically designed. If the building

designer is relying on the sheathing to

support the mechanical load or other heavy

load, it is important that the building

designer verify the sheathing thickness and

capability. Mechanical loads may produce

sufficient vibration to be considered in the

truss design. Such loads may require

additional trusses or custom design.

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3.04

SPECIFYING / DESIGNING

Information Required for Truss Design

Specified Design Loads

Trusses are required to transfer various types of

loads down to the support structure. Ultimately

all loads must be carried down to the foundation

of the structure. Truss design (specified) loads

include both live and dead loads which may be

uniformly distributed or concentrated at various

locations. These loads consist of gravity loads,

wind loads, earthquake loads, snow loads, rain

loads, etc.

Referenced within the IBC, the standard that

deals with loads is the American Society of Civil

Engineers (ASCE) standard, Minimum Design

Loads for Buildings and Other Structures. The

latest version of this standard is published in

cooperation with the Structural Engineering

Institute (SEI) and is referenced as SEI/ASCE7, or

commonly as “ASCE7” where the last two digits

reference the year the standard was published.

ASCE7 is the reference standard that a Building

Designer will use when determining what loads a

building element must resist.

It is the responsibility of the Building Designer to

specify all the loads that the framing members

will encounter and communicate them to the

truss designer. The truss designer will use those

Special Conditions

• Jobsite conditions that may cause rough handling of the trusses.

• High moisture or temperature conditions.

• Extreme environmental exposures that may cause corrosion to CFS members.

• Use of trusses to transfer wind or seismic loads to the supporting structure.

• In-plane and out-of-plane loads, such as lateral loads, are examples of loads that are

required to be transferred to the supporting structure.

• Fire resistance requirements.

• Higher adjacent roofs that may discharge snow onto lower roofs.

• Location from coastline, building exposure, building category and height

above ground for wind.

• Parapets, signage or other obstructions that may cause snow drifting or prevent the free

run-off of water from the roof. These types of building elements may also induce additional

dead loads that must be applied to the trusses.

• Any other condition that affects the load carrying ability of the roof or floor framing.

• Floor trusses, office loads or ceramic tiles require special considerations during the

building and truss design process.

loads when designing the truss system, so it is

very important that the specification of these

loads be both thorough and clear.

Live/Environmental Loads: These loads are

non-permanent loads. Examples include the

weight of temporary construction loads and

occupant floor loads. Environmental loads are

produced by snow, wind, rain or seismic events,

are usually uniform in their application, and are

set by the building codes or the building

designer. They will vary by location and use, and

should be furnished in pounds-per-square-foot

or other clearly defined units.

Dead Loads: Dead loads include the weight of

the materials in the structure and any items

permanently placed on the structure.

Special Loads: Special loads can be live or

dead. Examples of special loads might include

mechanical units, poultry cages, cranes,

sprinkler systems, moveable partition walls, attic

storage, etc. The weight, location and method of

attachment must be provided to the truss

designer. Multiple load cases may be required in

truss design.

Rebuilding the Pentagon

Allowable Shear Loads per Double-Shear Fastener

LBS (kN)

Tube Web Thickness Chord Thickness in Mils (GA)

Mils (GA) 28 (22) 33 (20) 43 (18) 54 (16) 68 (14) 97 (12)

33 (20) 700 (3.11) 772 (3.43) 878 (3.91) 995 (4.43) 995 (4.43) 995 (4.43)

47 (18) 779 (3.47) 977 (4.35) 1263 (5.62) 1348 (5.60) 1348 (5.60) 1348 (5.60)

63 (16) 779 (3.47) 977 (4.35) 1263 (5.62) 1348 (5.60) 1348 (5.60) 1348 (5.60)

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3.05

SPECIFYING / DESIGNING

TrusSteel System

Chord members

Chord members are available in three series:

TSC2.75, TSC3.00 and TSC4.00. Available in a

variety of material thicknesses, chords may be

intermixed within a truss to achieve the most

efficient truss designs. All steel conforms to

ASTM A653 and A500 standards. See the table

in this Section, and the TrusSteel Standard

Details, for member properties.

Web Members

Web members are either closed welded

rectangular steel tubes or patented, proprietary

roll-formed z-webs. Members are available in

many dimensions and thicknesses, and are used

in trusses as needed for their individual strength

and stiffness.

Pitch Break Connectors

Internal connections between truss chords are

made using patented pitch break connectors.

These internal connectors allow for the assembly

of very consistent joints at critical points such as

at the truss peak.

Installation Hardware

A full line of installation hardware is available for

attaching TrusSteel trusses to steel, CFS,

concrete and wood supports as well as to other

trusses. All hardware components are load rated

- see Section 5 for details.

Double-ShearTM Fasteners

TrusSteel trusses are assembled using the

patented #14 Double-Shear self-drilling tapping

fasteners. This technology provides a rigid, bolt-

like connection at all chord-to-web intersections.

Each fastener employs an integral washer and

Anti-BackoutTM technology to resist movement

and back-out. Color-coded, marked fasteners

create the most dependable, easily inspected

connection available for CFS materials. These

fasteners also allow the single-sided fabrication

of trusses (truss assembly without “flipping”

trusses). Refer to Standard Detail TS011 for

allowable shear loads per fastener into various

thicknesses of steel.

Galvanization

TrusSteel chords, webs and hardware

components are galvanized for protection

against corrosion during fabrication and

installation. Most TrusSteel components have G-

90 galvanized coating. TrusSteel’s galvanization

protection far exceeds the industry standard G-

60 coating.

The unique, patented shape of TrusSteel chord members gives them

exceptional strength and stiffness. Combined with the TrusSteel webs,

connectors and the patented Double-ShearTM fasteners, these elements can

create CFS trusses that have the highest strength-to-weight ratio in the

industry.

Notes

1. Based upon the material thicknesses of TrusSteel members.

2. Double-Shear fasteners include 14AMDB1.25, 14AMDR1.5, 14AMDB2.125, 14AMDR2.375.

3. Fastener values were determined by tests following guidelines set forth in Chapter F of the 2007

edition of the North American Specification for the Design of Cold-Formed Steel Structural Members

Typical pitch break connection

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3.06

SPECIFYING / DESIGNING

TrusSteel System

Product Identification

For easy identification, each chord is stenciled

with the following chord information (example

shown in parenthesis - see photo):

• Designation (43TSC4.00)

• ICC-ES Legacy Report (NER 529)

• Size (2.5 x 4.00)

• Mil thickness (43)

• Yield strength of steel (55 KSI)

• Chord galvanization (G-60)

• UL Recognized Component Mark

• TrusSteel name

• Patent number

Double-ShearTM fasteners have head markings

that show the Alpine delta logo (see photo).

Heads are color-coded according to size and use

in the truss.

Additional Info

Refer to the TrusSteel Standard Details for additional

information regarding the physical and structural

properties of TrusSteel components. These Details are

considered an adjunct to this manual and they are

available in CAD formats from www.TrusSteel.com and are

also on the electronic version of this manual.

Cross-Section

Taken through TrusSteel chord and web,

showing the Double-Shear fasteners. TrusSteel chord markings

As shown in a typical bundle of TSC4.00 chord material.

TrusSteel Member Properties

In inches, unless noted otherwise

Member Width Height Throat Fy KSI (MPa) Available Mils (GA) Galvanization

TSC2.75 1-1/2 2-3/4 3/4 55 (379) 28 (22), 33 (20), 43 (18) Min. G-60 or equivalent

TSC3.00 2-1/2 3 1-1/2 55 (379) 28 (22), 33 (20) 43 (18), 54 (16) Min. G-60 or equivalent

TSC4.00 2-1/2 4 1-1/2 55 (379) 28 (22), 33 (20), 43 (18), 54 (16) Min. G-60 or equivalent

50 (350) 68 (14), 97 (12)

Tube Webs various 45 (310) 33 (20), 47 (18), 63 (16) Min. G-60 or equivalent

Z-Webs various 40 (275) 33 (20), 43 (18) Min. G-60 or equivalent

Width

Throat

Depth

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3.07

SPECIFYING / DESIGNING

Wind Loading

Design Responsibility

It is the responsibility of the building designer to

communicate the wind loading requirements to

the truss designer. This includes (but may not be

limited to) all of the factors described in the Wind

Load Factors list shown in this section. The

building code utilized by the local jurisdiction will

outline the wind loading requirements for a

structure either explicitly or by reference. For

instance, the International Building Code (IBC),

2009 edition, references that the American

Society of Civil Engineers (ASCE) standard

ASCE7-05 be used to determine the wind load

applied to a structure.

Vertical Loads and Uplift Loads

Trusses resist wind loads, which include any

loads applied to trusses by the wind when it

encounters a structure. When wind encounters a

surface of a structure, it creates a load on that

surface which must be resisted and transferred.

As wind encounters the roof surface of a

building, it creates loads on those surfaces that

act perpendicular to the surface and can be in

either an inward direction or an outward

direction.

Engineers typically call a load acting inward to

the roof surface a downward load from wind. A

load acting outward to the roof surface is called

an uplift load. The directions of these loads are

dependent on geometric factors associated with

the building. The magnitudes of these loads are

dependent on many factors, including wind

speed, wind direction, site geometry, site

location, building geometry and building type.

Since wind loads act in a direction that is

perpendicular to the roof surfaces, a sloped roof

surface will have a component of this load that

acts in a vertical direction and a component of

this load that acts in a horizontal direction.

Supporting trusses resist vertical loads, which

they eventually transmit down to the building

components that support the trusses (walls,

girders, etc.). Supporting trusses must also resist

uplift loads transmitted from the roof surface.

These uplift loads produce uplift reactions at the

truss supports that must be resisted.

Lateral Loads

Since roof structures are typically framed entirely

with trusses, it is necessary for trusses to resist

the horizontal component of a wind load, often

called a lateral load.

A truss can resist a lateral load if the truss is

attached directly to its supports in a manner that

is adequate to transfer this load into the truss

support. To do this, the truss support itself must

be designed to receive and resist this load and

ultimately transfer it down to the building

foundation. If the truss-to-support connection

does not resist this load adequately, a truss can

slide off its supports when a horizontal load is

applied.

Another way to resist a horizontal load, which is

more common in modern building design, is to

transmit the load through a diaphragm.

Diaphragms are built of structural sheathing that

is directly applied to the truss top and/or bottom

chords. Common types of structural sheathing

are corrugated metal deck (e.g. B-deck) or wood

structural panels (e.g. plywood). A diaphragm

acts like a beam in that it takes the horizontal

load component applied to many trusses and

transfers it out to building elements that are able

to resist this accumulated horizontal load.

A truss that is used to transfer a diaphragm load

down to a resisting shear wall is commonly

referred to as a “drag truss” as it “drags” the

lateral load from the diaphragm to the shear

wall. If the building designer intends a truss to be

used as a drag truss to transfer lateral loads, it is

important that the loads be determined by the

building designer and transmitted to the truss

designer.

Stress Reversal

It is important to design a structure and its

elements to resist loads for winds coming from

all directions. When subjected to wind loads, the

internal members of a truss can experience a

stress reversal. A stress reversal occurs when a

member is subjected to a force that is in the

opposite direction as another stress from a

different type of load.

Cold-Formed Steel (CFS) trusses have performed

well when subjected to high wind situations such

as hurricanes, down bursts and tornados. Recent

hurricane activity in the United States

underscores the strong performance of CFS

trusses.

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3.08

SPECIFYING / DESIGNING

Wind Loading

For example, when designing a single truss, a

gravity load is a downward-acting load while a

wind load is typically an uplift or upward-acting

load. It is extremely important that each truss be

analyzed for a stress reversal situation, so that

each truss is designed to support every kind of

load that it may encounter.

Attachment to Supports

A wide variety of TrusSteel connection hardware,

with associated application details, is available

for anchoring trusses to the supporting structure.

These rated hardware connectors can be

installed to resist wind (uplift) loads, in-plane

lateral loads and out-of-plane lateral loads - in

any combination of these loads. It is imperative

that the building designer clearly define the loads

that a truss, and the truss connections, must

resist.

Demise of the Allowable Stress Increase

As a result of recent developments in the

standards associated with the design of CFS

members, designers are no longer able to

increase allowable stresses by 1/3 when the

loads are from wind or seismic events. In the

past, it was common practice to allow such

increases. This practice was supported by design

professionals, design specifications, loading

standards, and building codes for a century and

had deep roots in the design community. This

increase was allowed for seismic loads because

these loads were not considered until recently.

The rationale for the increase was that seismic

loads were intermittent and of short duration.

Research since that time has shown that steel

strength does not increase with load durations

typical of wind and seismic events, has improved

our accuracy in determining wind and seismic

design loads, and has resulted in changes in

design loads to account for the intermittent

nature and variability of such loads. One such

change permits a 25% reduction in live load

when two or more types of live load exist,

provided the 1/3 stress increase is not also

taken. This 25% reduction in load is identical to

a 1/3 increase in allowable stress, insofar as 3/4

is the inverse of 4/3, and has been confused as

being equal to the existing 1.33 increase factor.

However, this 25% reduction cannot be applied

to a load case consisting solely of dead plus wind

loads, which may govern the design of roof

trusses in high wind regions. For this reason, the

loss of the 1/3 stress increase factor may

increase the amount of steel in a member by as

much as 1/3. While such an increase is extreme

and not typical, it is likely that trusses in high

wind regions will show some greater material

thicknesses (gauges) of component sections on

occasion due to the removal of this factor.

The above change was first published in the

1970s and used by some designers instead of

the old 1/3 stress increase factor, but the old

factor remained available (and in use) until

recently. The IBC no longer permits the increase

factor for a load case of solely dead plus wind (or

seismic) load.

While it can be difficult to accept building code

changes that may cause increases in material

costs, this change is needed to assure that CFS

continues to show safe and consistent

engineering performance under severe loadings

like hurricanes and earthquakes.

The IBC no longer permits the increase factor

for a load case of solely dead plus wind (or

seismic) load.

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3.09

SPECIFYING / DESIGNING

Wind Loading

Notes

1. Values are nominal design 3-second gust wind speeds in miles per hour (m/s) at 33 ft. (10m) above ground for Exposure C category.

2. Linear interpolation between wind contours is permitted.

3. Islands and coastal areas outside the last contour shall use the last wind speed contour of the coastal area.

4. Mountainous terrain, gorges, ocean promontories, and special wind regions shall be examined for unusual wind conditions.

5. Regions outside the contiguous 48 states - refer to ASCE 7oryour local building official.

Determining the correct wind loads on individual structures can be very complicated, and it is important

to have a firm understanding of the way that a structure resists the wind. The following is a partial listing

of the factors that may have an influence on the wind loads used for the design of a truss:

• Geographic location of the building (to determine the basic wind speed, see “Basic Wind

Speed Map”)

• Height above ground

• Exposure category of terrain around the building being designed

• Building use

• Location of truss in building

• Location of building in relation to hills and escarpments

• Building dimensions

• Area of load carried by the truss

• Building porosity (open, closed or partially open)

• Dead load on the trusses to be considered for wind analysis (usually

less than the gravity design dead load).

Wind Load Factors

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3.10

SPECIFYING / DESIGNING

Snow Loading

Design Considerations

An important consideration in the roof design

process is the potential for varying types of snow

load conditions. Roofs and buildings that include

details or parapets and add-ons such as shed

roofs or solar panels need to be designed for

potential snow accumulation. Roof slope, surface

material textures and insulation may also affect

the potential for snow and ice accumulation.

The American Society of Civil Engineers (ASCE)

publishes Minimum Design Loads for Buildings

and Other Structures (ASCE7), which contains a

detailed procedure for determining snowdrift

loads. Regional characteristics such as

mountains, flat land and coastal and inland areas

can affect annual snowfall. Refer to the Ground

Snow Load Map, as published by ASCE.

The diagrams shown below are used to illustrate

some of the situations that may be encountered

when designing a roof system. Actual design

procedure as outlined in the applicable code

must be consulted when designing for snow.

Snow Loading

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3.11

SPECIFYING / DESIGNING

Seismic Loading

Seismic Events

Over sixty percent of the land area of the USA is

considered seismically active. Certain regions of

the country are more prone to heavy seismic

activity than other areas, examples being

California, Alaska and Hawaii. Structures in these

regions are required to be designed for specific

lateral loads imposed through seismic activity.

In a seismic event, slippage in the earth's crust

releases energy that is transmitted along the

surface of the earth as a series of waves, similar

to the way that waves travel across water when

the surface is disturbed. These waves can

produce an up-and-down motion, a sideways

motion, or both.

The type and severity of the motion depends on

the amount of initial energy released, the

distance from the epicenter, type of ground fault

and soil characteristics. The back-and-forth

movement can cause brief accelerations of 1g or

higher in strong earthquakes. This ground

vibration changes its magnitude throughout the

duration of a seismic event. The vibrations

usually taper off, or dampen, in a few seconds,

although the waves can continue for several

minutes. Aftershocks are earthquakes of lesser

magnitude than the main earthquake. They may

occur for hours or days after the main

earthquake and originate near the initial

epicenter.

Seismic Design Categories

The International Building Code assigns a

Seismic Design Category to each location in the

USA based on earthquake probability, occupancy,

and soil characteristics. Categories A and B are

assigned to locations that do not require any

seismic design. Structures built in Category C

locations require some special detailing, but one

and two family dwellings are exempt from the

seismic provisions. Categories D1, D2, and E

require successively more load resistance and

attention to prescriptive details.

Map shown for illustration purposes only. See the IBC or ASCE7 for actual seismic loading maps and data.

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3.12

SPECIFYING / DESIGNING

Seismic Loading

Diaphragms

In most instances when buildings with trusses

require seismic or wind analysis, the lateral

forces on the building are resisted by a system of

diaphragms. Roofs and floor planes covered with

wood sheathing (plywood or OSB) or metal decks

can be designed to create “horizontal”

diaphragms that can resist lateral loads. Vertical

members such as exterior walls and interior

shear walls are connected to the horizontal

diaphragms and to the building foundation to tie

the entire structure together. Specific trusses

may be designed to be located directly over the

shear walls to transfer the horizontal load from a

portion of the roof to the shear wall. These

trusses are called “collectors,” or “drag trusses,”

because they collect the forces from the

diaphragms and transmit them to the shear

walls. Determination of the required location,

loading and connections for these drag trusses is

the responsibility of the building design

professional.

The model codes publish tables of shear values

for plywood panel systems and the metal deck

manufacturers publish their own proprietary

values. Typically, shear panel systems designed

using the code tables specify nail or screw

patterns for the perimeter of the diaphragm and

for the interior edges of the individual structural

panels within the diaphragm.

CFS Trusses and Seismic Resistance

Buildings in earthquake-prone regions should be

designed to protect occupants during a

reasonably probable seismic event. Damaging

earthquakes have large motions but are usually

short in duration, lasting only a few seconds. This

is fortunate because the longer an earthquake

lasts the more damage it can cause. All types of

structural members and connections can fail

during long load cycles, as material fatigue

occurs or connections slip apart.

CFS (Cold-Formed Steel) trusses are well suited

for use in seismic applications. They are light in

weight so the forces are low. They are quite stiff

for their weight, so lateral displacements are

minimized. They are also ductile which means

that trussed systems are more likely to deform

under overload than to fail suddenly.

In some structures trusses must be designed to

resist horizontal loads generated by the sideways

acceleration of their own mass during an

earthquake. This requirement is usually ignored

because the connections designed for gravity

loads and wind uplift loads are judged sufficient

to withstand any lateral loads that might occur. If

the roofing materials assembly is sufficiently

heavy and the seismic event severe enough the

building designer may require the inclusion of

additional loads during analysis or the use of

special connections.

Another common horizontal load on trusses

occurs when wind or seismic motion are

imposed perpendicular to a wall that supports

the trusses. In this case a concentration of load

is induced into the heel of the truss that must be

transferred up to the roof diaphragm. This is the

opposite of a drag truss load, where the load

along the roof must be transferred to the wall

below. In either case the connections between

the horizontal diaphragm and the vertical support

are critical to the safe design of the structure.

12345678

3.13

SPECIFYING / DESIGNING

Sound Control

The Mass Law

The amount of sound, or vibration, which is

transmitted through floors, walls and ceilings is

governed by the Mass Law, a theoretical rule that

relates the mass per unit area to the control of

airborne sound. The Mass Law equation

estimates that each time the frequency of

measurement or the mass per unit area of a

single layer is doubled, the sound transmission

loss (STL) is increased by about 6 decibels (dB).

A 6 dB reduction in sound provides roughly a

25% reduction of the original sound level,

contingent upon other factors such as

temperature and the frequency (Hz) of the sound.

In construction terms, a 4 inch thick concrete

floor has a sound transmission loss (STL) of 42

dB at 250 Hz. Doubling the floor thickness to 8

inches only increases the STL to 48 dB. This

doubling in thickness (and mass) provides only

the 25% reduction in transmission loss

described above. This is not an acceptable

solution in today’s construction market.

Sound Control

The subject of sound transmission is situation, or

construction project, specific. The source of the

sound or noise may be airborne, or structure-

borne, or a combination of both. Typically the

elimination of airborne noise requires a reduction

in the energy level of the sound waves, which are

created by fluctuations in atmospheric pressure

reaching the eardrum. Structure-borne noise is

created by unwanted vibrations. The designer

should select, from the outset, the system and

products that will deliver the appropriate results.

It is normally far more economical to integrate

the solution into the initial design than to attempt

to create an “add-on” solution during the

construction phase.

There are a number of companies specializing in

the engineering of noise control systems.

Because increasing mass is no longer the

solution of choice, these companies design

systems and products that create an interruption

in the noise path or create a containment barrier

(at the source) to prevent the noise from reaching

the receiver. These companies use four basic

tools to combat noise transmission: absorption,

barriers, damping and vibration isolation. A

number of products, from decking and fabric

barriers to mechanical devices, are used to

address specific transmission loss needs.

Resources

In general, many sound control design methods,

products and applications that work with other

framing systems can work with CFS framing.

Some of these products have been tested in CFS

applications and the product manufacturers have

published data on these applications. The

building designer who is striving for a particular

sound control solution should carefully examine

the manufacturer’s published data as well as

data published by independent researchers.

Here is a small sampling from the wide range of

valuable informational sources on sound control:

Steel

Framing

Alliance

(SFA)

www.steelframingalliance.com

Residential Steel Framing – Builder’s Guide

to Fire and Acoustical Details, prepared for

The U.S. Department of Housing and Urban

Development (HUD) and the Steel Framing

Alliance by the National Association of

Home Builders (NAHB) Research Center,

Inc (2004).

North

American

Insulation

Manufacturers

Association

(NAIMA)

www.naima.org

Unwanted Sound

The transmission of unwanted sound,

classified as noise, is one of the most

common complaints made by the

occupants of modern buildings. This

problem has grown in recent years as

material suppliers have developed

products and construction methods to

reduce the weight of building components.

The goal has been to conserve material

and reduce both component cost and

construction time. Unfortunately, the goals

of lighter weight building materials and the

containment of noise often come into direct

conflict.

Noise Is Measured in Decibels (dB)

Whispers: about 20 dB

Normal conversations: about 60 dB

City traffic: about 80 dB

Lawn mower/leaf blower: about 103 dB

Repeated exposure to sounds over 85 decibels is considered dangerous to hearing, and the

louder the noise, the less time it takes to damage hearing.

Methods of Sound Propagation

reflection absorption transmission

1 2 34 5 6 7 8

3.14

SPECIFYING / DESIGNING

Sustainability & LEED

Checklist (Materials and Resources section)

allow the award of one point each for overall

building materials totals which exceed 5% (one

point) and 10% (one point) recycled content

(based on post-consumer + 1/2 post-industrial

content). Since local TrusSteel Authorized

Fabricators build TrusSteel trusses, attribution

toward further LEED points may be obtained

when TrusSteel trusses are obtained from an

Authorized Fabricator that is considered local to

the project. Project checklists of the available

LEED points are available from the USGBC.

Recycled Content

TrusSteel trusses are made with 100% U.S.

Prime steel. This steel is not only 100%

recyclable, it is composed of steel that is nearly

all recycled. According to the Steel Recycling

Institute, “steel used in structural steel building

products, whether produced via the EAF (electric

arc furnace) method or the BOF (blast oxygen

furnace) method can be used in the LEED

calculations to exceed both 5% and 10% goals.”

Further information on the LEED calculation may

be obtained from the USGBC and from the Steel

Recycling Institute publication, Steel Takes LEED

with Recycled Content.

The U. S. Green Building Council

The U. S. Green Building Council (USGBC) defines

itself as “the nation’s foremost coalition of

leaders from across the building industry

working to promote buildings that are

environmentally responsible, profitable and

healthy places to live and work.” Council-

sponsored consensus committees have

developed the Leadership in Energy and

Environmental Design (LEED) Green Building

Rating System in order to accelerate the

development and implementation of green

building practices. TrusSteel is proud to be a

member and supporter of the U.S. Green Building

Council.

LEED Standards

Currently, LEED-NC (New Construction) is a goal-

oriented standard whereby point-based goals are

set for specific areas of building design, with

point awards based upon green-oriented criteria

such as reduced site disturbance, increased

energy performance, resource reuse, use of

materials local to the site and the specific

recycled content of building materials. Sections

4.1 and 4.2 (Recycled Content) of the LEED-NC

Information Resources

Here are Web sites where you can learn more about the USGBC,

calculating LEED percentages and steel recycling:

U.S. Green Building Council (creators of the LEED standards)

www.usgbc.org

Steel Recycling Institute

www.recycle-steel.org

American Institute of Steel Construction (AISC)

www.aisc.org

1 2 34 5 6 7 8

3.15

SPECIFYING / DESIGNING

Fire Resistance & UL

TrusSteel and UL

Building codes often have requirements that

building elements perform for a specific period of

time when subjected to the elevated

temperatures associated with a fire event, based

upon the defined type of building/occupancy. One

of these requirements is that the building

element must withstand a fire event while

supporting a specific load. One method of

documenting this performance is by testing at

Underwriters Laboratories, Inc. (UL). UL has the

ability to perform fire tests on building elements

and assemblies according to standards

published by the American Society of Testing and

Materials (ASTM). Building elements and

assemblies that pass this testing qualify as

Listed UL assemblies.

Building assemblies containing TrusSteel trusses

have been tested at UL, and these assemblies

have been Listed as having 1 hour, 1-1/2 hour

and 2 hour fire resistive properties as described

and when utilized as described in the UL reports

listed in this Guide. TrusSteel has earned the UL

Classification Mark as to its fire-resistive

properties. This mark appears on TrusSteel

members for easy identification.

Insurance rating bureaus and many Federal,

state, county and municipal authorities and

inspectors recognize UL listings. The building

designer is responsible for determining the

suitability of use for UL Listed assemblies in

specific building designs.

Online Updates

Underwriters Laboratories (UL) Listed Fire

Resistive Designs with TrusSteel trusses have

proven to be key documents in gaining the

confidence and specifications of architects,

engineers and end users. TrusSteel Listed Fire

Rated Assemblies have also proven to be living

documents, undergoing frequent updates as

TrusSteel, along with our partner companies in

these listings, continues to expand the Listings to

include different materials and material

configurations. For this reason, we do not provide

a printed copy of these Listings but rather

encourage designers to visit the UL Web site and

view or download the most current Listings. To

find these Listings, point your browser to

http://www.ul.com and search on the Design

Numbers listed in this Guide, or perform a

keyword search for “TrusSteel” under the

Certifications section of the website.

UL Listings TrusSteel products qualify for hourly ratings as shown below.

Assemblies

TrusSteel components bear the UL Recognized

Component mark.

1 2 34 5 6 7 8

3.16

SPECIFYING / DESIGNING

Trusses as Building Components

Efficient Components

Trusses are versatile and efficient framing

components. They are available in an almost

infinite combination of profiles, depths, and

internal web patterns, depending upon the

required building geometry and loads. The great

efficiency of trusses comes as the result of the

custom-design of almost every truss for its

particular location and application.

Truss Profiles

Truss profiles are usually the result of the need to

create specific roof planes and perimeter

conditions. Truss depths are usually driven by

roof planes and heel heights, but are also driven

by the need to create strength.

Truss Web Patterns

Truss web patterns are generated by the truss

designer to create the most efficient truss. Web

patterns are often tailored to allow more efficient

truss bracing. Patterns can also be tailored to

create clear paths (runs or chases) through the

web pattern to allow the passage of ductwork.

The creation of these runs can speed the

installation of mechanical systems.

Available Combinations

The trusses in these charts represent a fraction

of the possible combinations of truss span, load,

profile and depth. If you have a specific truss

configuration and you need load/span

information, please contact your local Authorized

TrusSteel Fabricator. You can find a list of these

Fabricators on www.TrusSteel.com.

Fink

Howe

Double Fink

Double Howe

Double Fink Scissor

Howe Scissor

Room-in-Attic

Hip Girder

Flat Truss

(Warren pattern)

Sloping Top Chord

(Howe pattern)

Scissor mono

Mono

Note: Truss bracing not shown for clarity.

1 2 34 5 6 7 8

3.17

SPECIFYING / DESIGNING

Roof Truss Systems - Framing Styles

Introduction

Framing with trusses gives the building designer the versatility to accomplish a multitude of

interior and exterior building geometries while allowing the inside of the building to be free of

any supports. Within any roof style there are many truss framing methods or systems. These

systems can vary based on framing material (steel or wood), the experience of the designer, and

even vary from region to region. However trusses are designed and regardless of the roof style,

the challenge is to create a truss system that is efficient both to fabricate and to install. A few of

the more common framing systems for steel trusses are described below. Please note that the

names given to specific trusses, truss conditions and framing systems can vary from region to

region. Ceiling lines may be flat or sloped. Sloped ceilings have some limitations, so please

consult the truss designer.

Hip Systems

A hip roof framing system allows a roof area to

have a sloping roof plane rising from every wall

segment. This system uses smaller trusses (jack

trusses) that are placed at 90 degrees to the

front wall (see illustration). A truss (hip jack) runs

directly underneath the hip ridge line and spans

at an angle different from the other trusses. Hip

jack trusses are supported by a larger truss

(sometimes called the #1 hip truss) that spans

the width of the building and is located a short

distance (setback distance) from the front wall.

For best efficiency of the stepdown hip system, a

good rule of thumb is to keep the setback

distance to less than 10 feet. A hip system offers

the benefits of clear span with an eave or fascia

line maintained at the same elevation around the

building. The end slope may be equal to or

different from the side slope.

Typical Stepdown Hip System

1 2 34 5 6 7 8

3.18

SPECIFYING / DESIGNING

Roof Truss Systems - Framing Styles

Gable and Valley Systems

Gable System

A gabled roof system allows a framed area to

have a vertical plane coming off an end wall.

This framing system gives the appearance that

the vertical plane of the end wall extends up to

the roof plane. The trusses in this system span

the width of the roof area and can be of the same

profile throughout the length of the building

provided other interior or exterior geometry

changes do not occur. The first truss is located

on the end wall and is called the gable end truss.

The gable end truss, unlike the other trusses in

this system, is typically supported continuously

by the end wall for vertical loads, and resists the

horizontal wind load and transfers that load to

the building diaphragm. Because of its unique

role, the gable end truss may have a different

web pattern and may require different types of

bracing than the common trusses. A gable end

truss will typically have vertical webs spaced at

16” or (no more than) 24” on center, to resist

lateral wind loads and to accommodate the

attachment of sheathing. Gable end truss

vertical webs, when sheathed, will act like wall

studs.

Valley System

Valley trusses are generally supported by the

clear-span trusses below to form new,

intersecting ridge lines. Valley trusses can be

attached directly to the top chord of the

supporting trusses below or directly to the roof

decking (see photo).

Note: Truss bracing not shown for clarity.

Typical Gable & Valley System

1 2 34 5 6 7 8

3.19

SPECIFYING / DESIGNING

Roof Truss Systems - Piggybacks

Cap truss installed on top of base truss. Note

continuous bracing on top chord of base truss

and connection clip.

Applications

There are instances when a roof truss

application, due to a combination of roof pitch

and truss span, will require trusses that would

be too tall to build, deliver or handle

economically. In such instances, two or more

trusses can be built and delivered which will,

when installed together, do the work of each

single, oversized truss. Of these two trusses,

the bottom component is called the base truss

and the truss that rides on top is called the

piggyback or cap truss (see illustration). As a

rule of thumb, individual trusses that would be

over ten to twelve feet tall would probably be

candidates for a piggyback system.

Installation Sequence

During installation, piggyback system base

trusses are installed first and proper bracing is

installed for the base truss set. Base trusses

must be installed to resist the uplift forces of the

entire piggyback system. Bracing of the top

chords of the base trusses is essential and is

often accomplished using roof decking/

sheathing or continuous purlins. This bracing

must be completed prior to the installation of the

cap trusses.

Cap trusses are then attached to the base

trusses in a proper manner to resist lateral and

uplift forces. Connections of the cap trusses to

the base truss set are sometimes made using

proprietary connectors (see Section 5). Decks or

purlins for the roof membrane system may then

be applied to the cap trusses.

During design and estimation, designers and

contractors will want to account for these

additional materials as well as for the fasteners

required to install decking, purlins, clips, etc.

Additional labor may be required to install these

materials and the piggyback trusses.

Piggyback System

1 2 34 5 6 7 8

3.20

SPECIFYING / DESIGNING

Roof Truss Systems - Piggybacks

Standard Details

Several TrusSteel Standard Details are available

to assist the designer in understanding and

detailing piggyback systems. These Details may

be downloaded from www.TrusSteel.com or from

the electronic version of this manual. Detail

TS003A is shown below as an example.

Rafting

Piggyback truss systems, when properly

designed and braced, can be candidates for the

installation technique known as rafting. See

Section 7 of this manual for more information on

rafting.

Required Information

The Truss Designer will need the following

information about the roof system before

designing the piggyback system:

• all roof conditions that could require trusses

whose height will exceed the maximum

allowable truss height (candidates

for piggybacking)

• type of continuous framing / support to be

used on top of the base trusses (roof

decking/sheathing or continuous purlins)

• type of clip to be used to attach the piggyback

trusses to the base trusses or to the roof

decking/sheathing.

1 2 34 5 6 7 8

3.21

SPECIFYING / DESIGNING

Roof Truss Systems - Overhangs & Cantilevers

Truss Heels

The end of a truss is also known as the heel of a

truss. All trusses have two heels, one at each

end. The heel height of a truss is the distance

from the top edge of the top chord to the bottom

edge of the bottom chord at the heel (see

illustration).

Minimum Heel Heights for

TrusSteel Trusses

Due to the internal configuration of heels for non-

parallel chord trusses, these trusses have a

minimum heel height (see table below). TrusSteel

trusses can be fabricated with lower-than-

minimum heel heights. Using greater than

minimum heel heights can help create more

efficient trusses.

Minimum Heel Height Table

Heel height in inches

Roof Chord Size

Slope TSC2.75 TSC4.00

________________________

2 5-9/16 8-1/16

3 5-5/8 8-1/8

4 5-11/16 8-1/4

5 5-3/4 8-3/8

6 5-7/8 8-1/2

7 5-15/16 8-11/16

8 6-1/16 8-13/16

9 6-3/16 9

10 6-3/8 9-1/4

11 6-1/2 9-7/16

12 6-11/16 9-11/16

Overhangs and Cantilevers

Most designers who place pitched roofs on

buildings design those roofs with perimeter

overhangs. Overhangs can be accomplished with

trusses by extending the top chords of trusses

(overhangs), or by cantilevering the ends of the

trusses out past the perimeter bearing support

(see illustration). Cantilevered trusses are

generally more efficient trusses than those with

overhangs, and can simplify the installation of

fascia and soffit materials. A cantilevered truss

can also have a top chord overhang.

Standard Heel

Standard Heel with Overhang

Standard Heel with Boxed Return

Cantilevered Heel

Heel height

Cantilever distance

Common Heel Conditions

1 2 34 5 6 7 8

3.22

SPECIFYING / DESIGNING

Sample Tables

Each TrusSteel truss is engineered

individually to meet the load, span, spacing

and geometry requirements of a specific

project. There are literally millions of possible

combinations. These tables show a small

sample of those combinations, based on the

most common design criteria and simple

common trusses.

Contact your local TrusSteel Authorized

Fabricator to obtain truss designs for your

specific project needs.

General Notes:

1) Spans shown in charts are in feet.

2) Loads shown above are outlined as Top Chord Live Load (TCLL), Top Chord Dead Load (TCDL) and

Bottom Chord Dead Load (BCDL).

3) Top chords are assumed to be restrained laterally by structural sheathing.

4) Bottom chords are assumed to be restrained laterally at intervals not to exceed 24 inches.

5) Deflection limits: Live Load - L/360, Total Load - L/240

6) Trusses designed in accordance with ASCE7-02 wind and these considerations:

• Wind speed shown in charts

• Exposure C

• Building category II

• Truss bearing elevation is 8’0”

• No topographic effect from escarpment or hill taken into consideration.

• Enclosed building

7) Certain truss span and pitch combinations may require a truss to be “piggybacked”

due to shipping restrictions.

8) Trusses in excess of 80’-0” are possible - refer to TrusSteel

Technical Bulletin TB991102.

For additional information regarding large span trusses, contact a TrusSteel Authorized Fabricator.

9) Scissor trusses described in this table are designed with a bottom chord pitch equal to half of the top

chord pitch (i.e. a 6/12 top chord pitch scissor truss will have a 3/12 bottom chord pitch). Many other

top/bottom chord pitch variations are possible.

10) Designs may include multiple material thicknesses (mils or gauges) for top and bottom chords as

determined by the designer using steelVIEW engineering software. Maximum steel thicknesses are

43 mils (18 GA) for the TSC2.75 chord and 54 mils (16 GA) for the TSC4.00 chord in table above.

11) Truss web patterns will be determined by the designer using steelVIEW engineering software.

Roof Truss Systems - Sample Spans

1 2 34 5 6 7 8

3.23

SPECIFYING / DESIGNING

Floor Truss Systems

Configurations

TrusSteel open web floor trusses are fabricated

with the same materials used in TrusSteel roof

trusses. The obvious advantage of an open web

floor truss over conventional joist framing is the

ease of equipment installation for the

mechanical, electrical and plumbing trades.

TrusSteel open web floor trusses may allow

greater clear-span capabilities and facilitate a

variety of bearing options. Truss depth and on-

center spacing will be determined by specific

loading and span requirements.

Serviceability

Serviceability parameters are specified by the

building designer and then trusses are designed

accordingly. In order to ensure a rigid floor

system, TrusSteel recommends a minimum live

load deflection criteria of L/360; more rigid

requirements may be specified. All TrusSteel

floor trusses are recommended to be fabricated

with a minimum of two patented Double-Shear

fasteners at all web-to-chord connections to

ensure rotational stability of the web and

increase product stiffness.

Girders

Multiple ply girders at stairwells and other

openings allow TrusSteel to provide the entire

floor framing package. These girders are

designed to carry concentrated loads at specific

locations and must be installed according to

approved shop drawings. Standard connection

details are provided with the truss package to

ensure proper installation and load transfer.

Truss bears on support member at the

truss heel.

Continuous strongback bracing provides

stability and reduces dynamic response of

truss system.

Duct work runs through optional integral

chase opening created in truss webs.

Truss girder (two-ply girder shown)

supports other CFS trusses.

Typical Floor Truss System

TrusSteel floor trusses provide the convenience

of open web members.

Note: Truss bracing not shown for clarity.

1 2 34 5 6 7 8

3.24

SPECIFYING / DESIGNING

Floor Truss Systems

Bearing Options

Multiple bearing options offer the building

designer flexibility in assigning bearing

elevations and coordinating with other structural

systems. While the majority of floor trusses bear

directly on the truss bottom chord, top chord

bearing can be an option to reduce the overall

building height. Mid-height bearing at both

exterior and interior beams can eliminate the

need for boxed framing and deliver a flat ceiling

throughout.

Dynamic Response

The dynamic response of a TrusSteel open web

truss floor system is greatly reduced by requiring

the installation of strongback bridging (generally

a 5-1/2” cee stud attached to vertical webs) at a

maximum of 10’-0” on-center. This load

distribution mechanism converts individual truss

components into a rigid floor system. Strongback

bridging may be attached to the truss web

members with standard single shear screws.

Deck Connections

Whether using a plywood sub-floor in residential

framing or metal deck with concrete in

commercial construction, deck attachment can

be achieved with screws or proprietary ring

shank pneumatically installed nails. TrusSteel

recommends a minimum steel thickness of 33

mils (20 GA) for the truss top chord in all floor

truss applications. The application of acoustical

and thermal gasket materials to the top chord

can reduce sound and thermal transmission.

Strongback splice - overlap one truss as shown.

Standard strongback installed on vertical webs.

1 2 34 5 6 7 8

3.25

SPECIFYING / DESIGNING

Floor Truss Systems - Sample Span Tables

Floor Truss Span Tables

The abbreviated span tables shown represent

only a small sample of the possible floor truss

load/span/depth combinations. Contact your

local TrusSteel Authorized Fabricator to discuss

your specific truss needs.

Allowable Duct Size Table

This chart shows a sampling of available duct

openings in web patterns that are available in

some of the most common floor truss

configurations. Sizes of allowable openings may

be affected by specific floor loading conditions.

Contact your TrusSteel Authorized Fabricator to

discuss your specific truss needs.

Allowable Duct Sizes

1 2 34 5 6 7 8

3.26

SPECIFYING / DESIGNING

Guide Specification - Section 05 44 00

Notes to Specifier

This section is based on products engineered

by ITW Building Components Group, Inc.,

which is located at:

1950 Marley Drive

Haines City, FL 33844

Tel: (888) 565-9181

www.TrusSteel.com

Truss Fabricators

A nationwide network of TrusSteel

Authorized Fabricators quote, build and

deliver the trusses (in the same business

model as wood trusses). For a list of

TrusSteel Authorized Fabricators, visit

www.TrusSteel.com.

Product

The TrusSteel Division of ITW Builing

Components Group, the Truss Component

Manufacturer, has a unique, proprietary Cold-

Formed Steel (CFS) chord section that, when

combined with a dedicated truss design and

engineering software package, allows local

fabricators to supply high quality, reliable

designs with great speed and flexibility.

The CFS trusses are light in weight and

easy to deliver, handle, and install, while

providing resistance to insect damage,

deterioration, shrinkage, fire damage, and nail

popping that can affect wood truss

assemblies.

The TrusSteel chord shape is a symmetrical

"U" shape that avoids the eccentric loading

conditions that often occur with non-

symmetrical chord shapes like common steel

"C" shapes, sometimes referred to as "back-

to-back" shapes.

Electronic Specifications

An electronic, text-only version of this

specification is available on the CD version of

the manual or from www.TrusSteel.com. This

specification is provided in text-only format

with a minimum of formatting for use in all

word processors.

Additional Notes in Specifications

This specification contains additional

explanatory notes and instructions. These are

indicated with a ## symbol and are printed in

gray text within the body of the specification.

SECTION 05 44 00

(Section 05425 in MasterFormat 1995)

PRE-ENGINEERED PRE-FABRICATED

COLD-FORMED STEEL TRUSSES

PART 1 - GENERAL

1.1 - SECTION INCLUDES

A. Pre-engineered cold-formed steel trusses.

B . Cold-formed steel framing accessories.

1.2 - RELATED SECTIONS

## Delete any sections below not relevant to this

project; add others as required.

A. Section 05 30 00 -Metal Decking (Section

05300 in MasterFormat 1995).

B. Section 05 40 00 - Cold-Formed Metal

Framing (Section 05400 in MasterFormat 1995).

1.3 - DEFINITIONS

A. Truss Component Manufacturer: The

manufacturer of the components that will be

assembled into trusses by the Truss Fabricator.

See MANUFACTURERS for acceptable Truss

Component Manufacturer.

## Delete the last sentence in the following

paragraph if acceptable Truss Fabricators are not

listed in PART 2.

B. Truss Manufacturer: The individual or

organization that assembles the Truss

Component Manufacturer’s components into

completed trusses. See MANUFACTURERS for

acceptable Truss Fabricators.

C. Truss Design Drawing: Written, graphic and

pictorial depiction of an individual truss.

D. Truss Design Engineer: Person who is

licensed to practice engineering as defined by

the legal requirements of the jurisdiction in

which the building is to be constructed and who

supervises the preparation of the truss design

drawings. In this case, the Truss Design

Engineer is the Truss Component Manufacturer.

E. Truss Placement Diagram: Illustration

identifying the assumed location of each truss.

1.4 - REFERENCES

## Delete references from the list below that are

not actually required by the text of the edited

section.

A. ANSI/AISI/COS/S100-07/S2-10: North

American Specification for the Design of Cold-

Formed Steel Structural Members; American Iron

and Steel Institute; 2007 edition including the

2010 Supplement.

B. ANSI/AISI/COFS/S200-07: North American

Standard for Cold-Formed Steel Framing -

General Provisions; 2007.

C. ANSI/AISI/COFS/S214-07/S2-08: North

American Standard for Cold-Formed Steel

Framing - Truss Design; 2007 edition including

the 2008 Supplement.

D. AISI/COFS - Practice Guide - CF06-1: Code of

Standard Practice for Cold-Formed Steel

Structural Framing; 2006.

E. ASTM A 370-09 - Standard Test Methods and

Definitions for Mechanical Testing of Steel

Products; 2009.

F. ASTM A 500-03a - Standard Specification for

Cold-Formed Welded and Seamless Carbon Steel

Structural Tubing in Rounds and Shapes; 2003.

G. ASTM A 653-09 - Standard Specification for

Steel Sheet, Zinc-Coated (Galvanized) or Zinc-

Iron Alloy-Coated (Galvannealed) by the Hot-Dip

Process; 2009.

H. CFSBCSI - Cold-Formed Steel Building

Components Safety Information; Cold-Formed

Steel Council (CFSC); 2008 edition with CFSB3

summary sheet insert.

I. CFSEI Technical Note 551d - Design Guide for

Construction Bracing of Cold-Formed Steel

Trusses; Cold-Formed Steel Engineers Institute;

February 1997.

J. CFSEI Technical Note 551e - Design Guide for

Permanent Bracing of Cold-Formed Steel

Trusses; Cold-Formed Steel Engineers Institute;

February 1998.

1.5 - SUBMITTALS

A. Submit under provisions of Section 01 30 00

(Section 01300 IN MF95).

B. Product Data: Truss Component

Manufacturer's descriptive literature for each

item of cold-formed metal framing and each

accessory specified in this section.

1 2 34 5 6 7 8

3.27

SPECIFYING / DESIGNING

Guide Specification - Section 05 44 00

C. Truss Design Drawings: Detailed drawings

prepared by Truss Manufacturer under the

supervision of the Truss Design Engineer that are

in accordance with AISI references. These

drawings may also include referenced detail

drawings germane to the trusses.

D. Truss Placement Diagram: Diagram that

identifies the assumed location of each

individually designated truss and references the

corresponding Truss Design Drawing.

E. Installation Instructions: Truss Component

Manufacturer's printed instructions for handling,

storage, and installation of each item of cold-

formed metal framing and each accessory

specified in this section.

1.6 - QUALITY ASSURANCE

A. Provide design of trusses by Truss Component

Manufacturer, using design methodologies

recommended in AISI references.

1. Determine mechanical properties of load

bearing components by testing in accordance

with ASTM A 370-09.

2. Provide drawings by a design professional

registered in the State in which project is to be

constructed.

3. Provide Truss Manufacturer’s Truss Design

Drawings.

B. Pre-Installation Meeting: Meet at job site prior

to scheduled beginning of installation to review

requirements:

1. Attendees: Require attendance by

representatives of the following:

a. Installer of this section.

b. Other entities directly affecting, or

affected by, construction activities of this section,

including but not limited to, the following:

1) Installer of truss support framing.

2) Installer of mechanical systems.

3) Installer of electrical systems.

2. Review potential interface conflicts;

coordinate layout and support provisions.

1.7 - DELIVERY, STORAGE, AND

HANDLING OF STEEL TRUSSES

A. Pack, ship, handle, unload, and lift shop

products in accordance with Truss Component

Manufacturer's recommendations and in manner

necessary to prevent damage or distortion.

B. Store and protect products in accordance with

Truss Component Manufacturer's

recommendations and in manner necessary to

prevent damage, distortion and moisture buildup.

PART 2 -PRODUCTS

2.1 - MANUFACTURERS

## ITW Building Component Group, Inc. (the

Truss Component Manufacturer) produces the

truss components, which are then assembled

into completed trusses by one of their approved

fabricators (the Truss Fabricator). Visit

www.TrusSteel.com or call 888-565-9181 for a

list of Truss Fabricators. A free TrusSteel Design

Manual CD is also available.

A. Acceptable Truss Component Manufacturer:

TrusSteel Division of ITW Building Components

Group, Inc.; 1950 Marley Drive, Haines City, FL

33844. Tel: (888) 565-9181.

www.TrusSteel.com.

## Delete the following paragraph if it is not

necessary to list acceptable Truss Fabricators.

Obtain from TrusSteel a current list of Approved

Truss Fabricators known to have the capability of

fabricating products described in this section.

List of TrusSteel Authorized Fabricators is

available from www.TrusSteel.com.

B. Acceptable Truss Fabricators: Truss

components shall be fabricated into completed

trusses by one of the following local fabricators:

1. _________________________________.

2. _________________________________.

3. _________________________________.

## Delete one of the following two paragraphs;

coordinate with requirements of Division 1

section on product options and substitutions.

C. Substitutions: Not permitted.

D. Requests for substitutions will be considered

in accordance with provisions of Section 01 60

00.

1. All substitutions must be approved in

writing by the Architect or Building

Designer.

2. All applications for substitution must

include samples and technical data.

2.2 - COMPONENTS

A. Pre-Engineered Pre-Fabricated Cold-Formed

Steel Trusses: TrusSteel truss components, by

ITW Building Components Group, Inc.; meeting

specified requirements.

1. Truss Type, Span, and Height: As indicated

on drawings.

## Insert name of local code and deflection

requirements.

2. Comply with requirements of

______________________ code.

3. Deflection Under All Loads : 1/______th of

span, maximum.

4. Deflection Under Live Loads: 1/______th of

span, maximum.

5. Shop fabricate in accordance with Truss

Design Drawings, using jigging systems to

ensure consistent component placement

and alignment of components, and to

maintain specified tolerances; field

fabrication is strictly prohibited unless

performed by authorized Truss

Manufacturer using Truss Manufacturer’s

shop assemblers and proper jigging

systems.

6. Shop fabrication of other cold-formed steel

framing components into assemblies prior

to installion is permitted; fabricate

assemblies in accordance with shop

drawings.

7. Fasten connections within truss assembly

with Truss Component Manufacturer’s

fasteners only and as shown on the Truss

Design Drawings; welding and other

fasteners are prohibited.

8. Fabricate straight, level, and true, without

rack, and to the tolerances specified in

ANSI/AISI/COGFS/S214-07/S2-08.

B. Truss Chord and Web Components:

TrusSteel components, with rolled or closed

edges to minimize the danger of cutting during

handling; chord and web components without

rolled edges are prohibited.

1. Shapes, Sizes and Thicknesses: As

required to suit design and as indicated

on shop drawings.

2. Chords: Cold-formed from ASTM

A653-06a galvanized steel sheet,

minimum G60 coating; minimum yield

strength of 55,000 psi (380 MPa).

1 2 34 5 6 7 8

3.28

SPECIFYING / DESIGNING

Guide Specification - Section 05 44 00

## Some TrusSteel chord members are

manufactured from ASTM A653 steel of a higher

grade with minimum yield strength of 55 ksi (380

MPa) and minimum tensile strength of 65 ksi (448

MPa)

a. Nominal 28 mil (22 GA) members:

1) Minimum bare metal thickness:

0.0284 inch (0.72 mm).

2) Maximum design thickness:

0.0299 inch (0.76 mm).

b. Nominal 33 mil (20 GA) members:

1) Minimum bare metal thickness:

0.0329 inch (0.84 mm).

2) Maximum design thickness:

0.0346 inch (0.88 mm).

c. Nominal 43 mil (18 GA) members:

1) Minimum bare metal thickness:

0.0428 inch (1.09 mm).

2) Maximum design thickness:

0.0451 inch (1.15 mm).

d. Nominal 54 mil (16 GA) members:

1) Minimum bare metal thickness:

0.0538 inch (1.37 mm).

2) Maximum design thickness:

0.0566 inch (1.44 mm).

e. Nominal 68 mil (14 GA) members:

1) Minimum bare metal thickness:

0.0677 inch (1.72 mm).

2) Maximum design thickness:

0.0713 inch (1.31 mm).

f. Nominal 97 mil (12 GA) members:

1) Minimum bare metal thickness:

0.0966 inch (2.46 mm).

2) Maximum design thickness:

0.1017 inch (2.58 mm).

3. Tube Webs: Cold-formed ASTM A500

steel structural tubing; minimum yield

strength of 45 ksi (310 MPa); minimum tensile

strength of 55 ksi (380 MPa).

a. Nominal 33 mil (20 GA) members:

1) Minimum bare metal thickness:

0.033 inch (0.84 mm).

2) Maximum design thickness:

0.035 inch (0.89 mm).

b. Nominal 47 mil (18 GA) members:

1) Minimum bare metal thickness:

0.047 inch (1.19 mm).

2)Maximum design thickness:

0.049 inch (1.24 mm).

c. Nominal 63 mil (16 GA) members:

1) Minimum bare metal thickness:

0.063 inch (1.6 mm).

2) Maximum design thickness:

0.065 inch (1.65 mm).

4. Rolled formed Webs: Cold-formed from

ASTM A 653/A 653M galvanized steel sheet,

minimum G90 coating; minimum yield strength

of 40 ksi (276 MPa) for 20 and 18 GA

components or 50 ksi (345 MPa) for 16 GA

components; minimum tensile strength of 55 ksi

(379 MPa) for 20 and 18 GA components or 65

ksi (448 MPa) for 16 GA components.

a. Nominal 33 mil (20 GA) members:

1) Minimum bare metal thickness:

0.0329 inch (0.84 mm).

2) Maximum design thickness:

0.0346 inch (0.88 mm).

b. Nominal 43 mil (18 GA) members:

1) Minimum bare metal thickness:

0.0428 inch (1.09 mm).

2) Maximum design thickness:

0.0451 inch (1.15 mm).

c. Nominal 54 mil (16 GA) members:

1) Minimum bare metal thickness:

0.0538 inch (1.37 mm).

2) Maximum design thickness:

0.0566 inch (1.44 mm).

C. Fasteners Used in Fabricating Trusses:

Fasteners as recommended by Truss Component

Manufacturer, bearing stamp of Truss

Component Manufacturer for ready

identification.

PART 3 EXECUTION

3.1 EXAMINATION

A. Verify that bearing surfaces and substrates are

ready to receive steel trusses.

## The tolerances appropriate for truss bearings

surfaces are dependent on required tolerances of

subsequent construction; coordinate with other

sections and modify as required.

B. Verify that truss bearing surfaces are within

the following tolerances:

1. Variation from Level or Specified Plane:

Maximum 1/8 inch in 10 feet (6 mm in

3 m).

2. Variation from Specified Position: Maximum

1/4 inch (6 mm).

C. Verify that rough-in utilities and chases that

will penetrate plane of trusses are in correct

locations and do not interfere with truss, bracing

or bridging placement.

D. Inspect conditions under which installation is

to be performed and submit written notification if

such conditions are unacceptable to installer.

1. Notify Architect/Engineer-of-Record within

24 hours of inspection.

2. Beginning construction activities of this

section before unacceptable conditions

have been corrected is prohibited.

3. Beginning construction activities of this

section indicates installer’s acceptance of

conditions.

3.2 - INSTALLATION

A. Install trusses in accordance with Truss

Component Manufacturer’s instructions and

Truss Manufacturer’s Truss Design Drawings.

Use correct fasteners as previously described.

B. Place components at spacings indicated on

the Truss Design Drawings.

C. Install all erection (temporary installation)

bracing and permanent bracing and bridging

before application of any loads; follow

recommendations of the CFSBCSI - Cold-Formed

Steel Building Components Safety Information.

D. Install erection bracing -follow

recommendations of CFSBCSI Cold-Formed Steel

Building Components Safety Information.

1. Provide bracing that holds trusses straight

and plumb and in safe condition until

decking and permanent truss bracing has

been fastened to form a structurally sound

framing system.

2. All sub-contractors shall employ proper

construction procedures to insure adequate

distribution of temporary construction loads

so that the carrying capacity of any single

truss or group of trusses is not exceeded.

E. Install permanent bracing and bridging as

shown in the Architect/Engineer-of-Record’s

drawings and notes and as shown in the Truss

Fabricator’s shop drawings.

F. Removal, cutting or alteration of any truss

chord, web or bracing member in the field is

prohibited unless approved in advance in writing

by the Architect/Engineer-of-Record and the

Truss Designer.

G. Repair or replace damaged chords, webs, and

completed trusses as previously directed and

approved in writing by the Architect/Building

Designer and the Truss Component

Manufacturer.

3.3 FIELD QUALITY CONTROL

## This article is optional.

A. Owner will provide inspection service to

inspect field connections; see Section 01 40 00.

1 2 3 45 6 7 8

ENGINEERING / SHOP DRAWINGS

Engineering

4.01

Design Responsibilities

The Committee on Framing Standards (COFS) of

the American Iron and Steel Institute has created

the Standard for Cold-Formed Steel Framing -

Truss Design (latest revision is AISI S214-07/S2-

08) to provide technical information and

specifications on CFS truss construction. Specific

design responsibilities are defined within the

Standard in Section B. While these definitions are

not intended to replace any other allotments of

responsibilities that may be agreed upon by

involved parties, they do provide a proven

framework for most projects. The

responsibilities, as defined in the Standard, are

given below:

The Building Designer

The Building Designer shall specify the following

information:

(a) design loads in accordance with Section C

of the Standard

(b) roof profile and geometry

(d) temperature and moisture environment for

the intended end use

(e) any special requirements or considerations

to be taken into the truss design.

The Building Designer shall provide for the

following in the design and detailing of the

building:

(a) horizontal, vertical, or other truss deflection

due to design loads

(b) truss movement due to temperature

changes

accommodating horizontal, vertical or other

reactions or displacements

(d) permanent truss bracing to resist wind,

seismic, and any other lateral forces acting

perpendicular to the plane of the truss

(e) permanent lateral bracing as specified by

the truss designer.

Truss Designer

The Truss Designer shall make available, upon

request, comprehensive design calculations

including the following information:

(a) loads and load combinations considered

(b) axial forces, moments, and shears

resulting from the applied loads and load

combinations

Truss Design Drawings

The truss design drawings shall include, as a

minimum, the following information:

(a) slope, depth, span, and spacing of the truss

(b) bearing locations and minimum bearing

lengths

(d) nominal reaction forces and direction

(e) location of all truss connections

(f) gusset plate locations, sizes and material

specification

(g) fastener type, size, quantities and

locations

(h) shape and material specification for each

component

(i) maximum nominal compressive force in all

truss members

(j) locations of required permanent truss

member bracing

(k) connection requirements for:

(1) truss-to-truss girder

(2) truss ply-to-ply

(3) field assembly of trusses

(l) calculated deflection ratio and / or

maximum deflection for live and total load.

The loads and load combinations to be used in

the design of cold-formed steel trusses shall be

determined by the building designer as

established by the local building code. In the

absence of such a code, the loads, and

combinations of loads shall be in accordance

with accepted engineering practice for the

geographical area under consideration as

specified by the appropriate sections of ASCE 7.

These and other reference materials are

available from the American Iron and Steel

Institute. See Section 8 of this Manual for contact

information.

1 2 3 45 6 7 8

ENGINEERING / SHOP DRAWINGS

Engineering

4.02

Information Flow

The flow of design responsibilities within a truss

project creates an information flow that must be

understood by all participants. Each participant

plays a key role in handling large amounts of

information.

Open communication during this process is

critical for the success of a project. This diagram

shows the flow of responsibilities and

information for a typical truss project.

Sample drawing

1 2 3 45 6 7 8

ENGINEERING / SHOP DRAWINGS

Shop Drawings

4.03

Shop drawings are the primary vehicle for

transferring design information from the truss

designer to the building designer for review.

Clear, easy to understand shop drawings make

the job of the reviewer easier and help speed the

approval process. Each individual truss design is

described with a unique shop drawing. Load,

span, deflection and other design parameters are

clearly stated. Special design criteria and

bracing requirements are given, and additional

details are referenced on the drawing. Every

truss component member, fastener and internal

connector is located and identified. Truss profile,

pitch breaks and bearing points are fully

dimensioned.

Individual shop drawings are often supported

with engineering details. These accompanying

details are referenced on the shop drawings and

are included with the shop drawings in the

submittal package. Common internal connection

situations are referred to appropriate Standard

Details. New details are created, as needed, to

describe unique situations.

Key to Illustration

A Truss materials

B Special design considerations

C Truss design

D Reactions (including uplift) and bearing width

E Other considerations

F Load and spacing design parameters

1 2 3 45 6 7 8

4.04

NOTES

1 2 3 4 56 7 8

5.01

CONNECTIONS / DETAILS

Overview & Applications

Trusses are connected to each other, as well as

to other building systems and bearings, through

the use of proprietary connectors (sometimes

called “connectors”). These proprietary

connectors, sold by Alpine, are manufactured to

Alpine specifications and form an integral part of

the complete TrusSteel system.

The following pages of this manual are an

introduction to these connectors and their use.

This introduction is not intended to be a

comprehensive technical guide for each

connection type. For complete technical data on

each connection, please refer to the TrusSteel

Standard Details.

All connectors attach to TrusSteel trusses with

standard self-drilling tapping screws.

Connectors attach to different bearing materials

through the use of a variety of screws, pins,

welds and embedded anchors.

Other Connections

The following connections are not shown in this

manual - please refer to the Standard Details:

• truss fabrication connections (chord to web,

chord to chord, etc.)

• assembly of multi-ply trusses (whereby

several trusses are connected side-by-side to

create one multi-ply truss)

• connection or suspension of mechanical loads

from trusses.

General Notes for All Connections

• Connectors and fasteners specified are

designed to support the loads listed in the

allowable tables on the TrusSteel Standard

Details and in this manual.

• Install connectors and fasteners as specified

on the TrusSteel Standard Details. Refer to the

Standard Details for important information not

shown in this manual.

• Allowable loads have not been increased for

wind, seismic or other factors.

• Install all fasteners and connectors prior to

loading the connection.

• Allowable loads are listed in imperial (LBS)

and metric (kN) units.

• All steel thicknesses given are actual base

metal thicknesses.

• Connectors are fabricated from

G-90 or equal galvanized steel.

Notes for Truss-to-Truss Connections

• Connections are designed to support vertical

loads only in an upward or downward

direction.

Notes on Truss-to-Bearing Connections

• Upward loads listed are MAXIMUM allowable

loads.

• For lateral load capacities, see the Standard

Details.

• If upward loads will be acting in combination

with lateral loads, please contact a TrusSteel

engineer to determine the adequacy of the

connection.

General Notes for Fasteners

The fasteners specified in this publication, and on

the Standard Details, shall be used in strict

accordance with the Details. If an “or equal”

statement appears within a Detail, the substituted

fastener shall be qualified by a professional

engineer prior to the installation of the substitute.

The allowable load capacity of the substituted

fastener shall be confirmed through reliable

published test data or calculations.

Notes on Self-Drilling Tapping Screws (SDS)

• Allowable loads are determined per the AISI

North American Specification for the Design of

Cold-Formed Steel Structural Members

• SDS shall comply with ASTM C1513 or an

approved design or recognized design

Standard

• #10 tapping screw is 0.19” (nom. dia.)

• #12 tapping screw is 0.216” (nom. dia.)

• #14 tapping screw is 0.25” (nom. dia.)

• Screw spacing, end and edge distance shall

be 3 times the nominal diameter.

• Screw point style to be determined, based

upon the recommended steel thickness for

the given style.

• Screw length to be determined, so that when

installed the screw shows three exposed

threads (out the back of the connected parts)

or as otherwise determined by a professional

engineer.

• References

- AISI/COFS/S200 North American Standard for

Cold-Formed Steel Framing - General

Provisions

- Technical Note F102-11, Screw Fastener

Selection for Cold-Formed Steel Frame

Construction, CFSEI, November 2011

CONNECTIONS / DETAILS

Overview & Application

1 2 3 4 56 7 8

5.02

Notes on Wood Screws

• Allowable loads shall be determined by

ANSI/AF&PA NDS

• All wood screws shall comply with ASME

Standard B18.6.1 or an approved design or

recognized design standard.

Notes on Hilti®Powder-Actuated Fasteners

• Shall comply with ICBO Evaluation Report

ER-2388.

• Allowable loads shall be determined by ICBO

Evaluation Report ER-2388.

• Shall comply with Hilti North American

Product Technical Guide, 2005.

Notes on ITW Buildex®TAPCON®Fasteners

• Shall comply with ICC-ES Legacy Report

ER-3370.

• Allowable loads shall be determined by

ICC-ES Legacy Report ER-3370.

• Shall comply with ITW Buildex Product

Catalog

ITW Building Components Group, Inc. shall not be responsible for any performance failure in a

connection due to a deviation from the Standard Details. Any variation from these Details shall

be approved in advance by Alpine Engineers.

Notes on Welds

• Electrode strength, weld size, length and

spacing shall comply with specifications as

shown on applicable TrusSteel Standard

Details

• Welds shall be designed in accordance with

the AISI North American Specification for the

Design of Cold-Formed Steel Structural

Members

• Welds and welding shall comply with

requirements of American Welding Society

(AWS) D1.3, Structural Welding Code - Sheet

Steel.

This Manual is intended for quick reference only. Drawings and illustrations shown are samples only and are not intended for detailing

or construction. Please refer to the TrusSteel Standard Details for technical information on connection design, product use and safety.

1 2 3 4 56 7 8

5.03

CONNECTIONS / DETAILS

Standard Details

Obtaining the Details

These Details are made available to the design community, free of charge, in DWG and DXF CAD

formats as well as in the printer-friendly PDF format. TrusSteel encourages designers to

incorporate these details directly into their construction documents.

Designers can obtain these Details via download at www.TrusSteel.com, or via the interactive

CD version of this manual. To request the CD, please send an e-mail to info@TrusSteel.com,

and include your name, your company name and your mailing address.

ITWBCG Hardware\

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Standard Details

TrusSteel has developed a library of Standard

Details to assist designers in their understanding

and use of these products. The library is divided

into sets of details, grouped by application. Set

names include:

• Bracing

• Connections: Mechanical/ Hanging

• Connections: Truss-to-Bearing

• Connections: Truss-to-Truss

• Product Properties

• Truss Framing Conditions

• Truss Internal Connections.

Details within these sets cover these applications

and more:

• truss to bearing connections (CFS steel, red

iron, wood and concrete bearings)

• truss bearing types (scissor, top and bottom

chord bearings)

• truss internal connections, including

- multi-ply trusses,

- splices

- pitch breaks

• truss bracing

• gable ends

• piggyback framing

• valley framing

• overhangs

• outlookers

• duct penetrations

• sprinkler and other hanging loads

• member section properties.

Sample Detail

1 2 3 4 56 7 8

5.04

CONNECTIONS / DETAILS

Right Angle (90º) Truss Web-to-Web Connections

Description

Right angle truss-to-truss connections may be

made at the truss vertical webs by using TTC

clips. TTC clips may be used to fasten supported

trusses to single, double and triple-ply girder

trusses. TSC2.75 chord trusses require TTC3

and TTC5 clips. TSC4.00 chord trusses require

TTC4 and TTC7 clips.

Fasteners

TTC clips are installed using industry-standard

#10 self-drilling tapping screws. See Standard

Details for fastener quantities and placement to

reach Maximum Reactions.

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of TTC clip

sizes and installation requirements:

TS001

TS001A

TS001B

TS001C

TS001D

TS001E

TS001F

Connections using TTC Clips

Connections using TSHDC Clips

Girder truss

TTC clip

Supported

truss

Connections with TTC clips may be made at either

heel or end web of supported truss.

Girder truss

TSHDC clip

Supported

truss

Description

TSHDC clips may be used to fasten supported

trusses to single, double and triple-ply girder

trusses with differing web dimensions. Please

refer to the appropriate Standard Details for

information regarding the selection of TSHDC clip

sizes and installation requirements (see table

below).

Fasteners

TSHDC clips are installed using industry-

standard #10 self-drilling tapping screws. See

Standard Details for fastener quantities and

placement to reach Maximum Reactions.

Connections with TSHDC clips may be made at either

heel (not shown) or at the end web of supported truss.

TrusSteel

Chord Size

TSC2.75

TSC4.00

Girder

Vertical Size

3/4” x 1-1/2”

3/4” x 2-1/4”

1-1/2” x 1-1/2”

1-1/2” x 2”

1-1/2” x 2-1/2”

1-1/2” x 3-1/2”

Type

of Clip

TSHDC1.52

TSHDC2.252

TSCC664

TSHDC2.04

TSHDC2.54

TSHDC3.54

Standard

Detail

TS059, TS059A, TS059B

TS060, TS060A, TS060B

Reference Standard Details and Clip Selection

Valid for one, two and three ply girders.

Maximum Reaction (R)

LBS (kN)

1976 (8.79)

2470 (10.99)

No. of Clips

Maximum Connection Reactions

Downward and Uplift

Valid for one, two and three ply girders.

Maximum Reaction (R)

LBS (kN)

3500 (15.57)

4700 (20.91)

Chord

Size

TSC2.75

TSC4.00

Maximum Connection Reactions

Downward and Uplift

1 2 3 4 56 7 8

5.05

CONNECTIONS / DETAILS

Right Angle (90º) Truss Chord-to-Chord Connections

Description

Right angle truss-to-truss connections may be

made at the truss chords by using TSJH-series

hangers. TSJH-series hangers may be used to

fasten supported trusses to single, double and

triple-ply girder trusses.

Fasteners

Hanger connections are made using industry-

standard #10 self-drilling tapping screws.

Allowable loads shown are for full fastener

patterns. There are also allowable load values

available based upon partial fastener patterns.

See the referenced Standard Details for more

information.

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of TSJH-

series hanger sizes and installation

requirements:

TS022 connecting to single ply girder trusses

TS022A connecting to single ply girder trusses

TS023 connecting to multi-ply girder trusses

TS024 connecting to multi-ply girder trusses

TS024A connecting to multi-ply girder trusses

TSC2.75 supported truss connection to TSC2.75

girder truss with TSJH22 Hanger.

Connections using TSJH Hangers

TSC2.75 supported truss connection to TSC4.00

girder truss with TSJH24 Hanger.

TSC4.00 supported truss connection to TSC4.00

girder truss with TSJH44 Hanger.

Allowable Load

LBS (kN)

Down

28TSC

22 GA

740 (3.29)

680 (3.02)

Maximum Connection Reactions

Downward and Uplift

TSC2.75 Girder with TSC2.75 Supported Truss

Using TSJH22 Hangers

Girder Chord Gauge

33TSC

20 GA

920 (4.09)

770 (3.43)

43TSC

18 GA

1380 (6.14)

1010 (4.49)

Allowable Load

LBS (kN)

Down

28TSC

22 GA

920 (4.09)

610 (2.71)

TSC4.00 Girder with TSC2.75 or TSC4.00

Supported Truss

Using TSJH24 and TSJH44 Hangers

Girder Chord Gauge

54TSC

16 GA

1360 (6.05)

1130 (5.03)

33TSC

20 GA

1140 (5.07)

780 (3.47)

43TSC

18 GA

1350 (6.01)

1010 (4.49)

1 2 3 4 56 7 8

5.06

CONNECTIONS / DETAILS

Variable Angle Truss Web-to-Web Connections

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of TTC clip

sizes, and the required quantities and placement

locations of fasteners:

TS025 45° corner set

TS025A non-45° corner set

TS056 rafters

TS056A rafters

Maximum Connection Reactions

Refer to the referenced Standard Details for

allowable loads.

Connections using TTC Clips

Supported

truss

TTC clip

Girder truss

Description

Truss-to-truss connections of variable angles

may be made at the truss vertical webs by using

TTC clips. TTC clips may be used to fasten

supported trusses to single-ply girder trusses.

They are especially useful for making

connections for hip jacks and corner jacks in hip

sets.

Fasteners

These connections are made with #10 self-

drilling tapping screws.

TTC clips may also be used for rafter

to truss connections.

Connections at Gable Outlookers Using ITWBCG Hardware Connectors

Outlooker “C” member

TSJH Connector

Fascia member End gable truss

(dropped-top gable)

HT2.5A

Description

In gable outlooker situations, CFS “C” framing

may be attached to TrusSteel trusses using

TrusSteel TSJH connectors and ITWBCG

Hardware HT2.5A connectors.

Fasteners

These connectors are attached to the trusses

and the “C” framing with #10 self-drilling

tapping screws.

Reference Standard Details

Please refer to the Standard Detail below for

information regarding the selection of HT2.5A

connectors and installation requirements:

TS041

Connections at Gable Outlookers

1 2 3 4 56 7 8

5.07

CONNECTIONS / DETAILS

Welded Connections to CFS Steel and Heavy Steel Bearings

Connections using WTC Clips

Description

CFS trusses may be anchored to both CFS steel

and heavy steel bearings using TrusSteel WTC

clips. Several sizes of WTC clips are available,

depending upon the required load transfer

capability.

Fasteners

These clips are attached to the truss with #10

self-drilling tapping screws and are attached to

the supporting members by welding. See

Standard Details for welding specifications.

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of WTC clips,

clip sizes, top plate minimums, installation

requirements and lateral load capacities:

TS027

TS027A

TS027B

TS027C

Welded connection to heavy steel using WTC Clip

Welded connection to CFS using WTC Clip

Chord Mil (GA)

28TSC (22)

33TSC (20)

43TSC (18)

54TSC (16)

TS6WTC3

Clip on One Face

550 (2.45)

Clip on Each Face

1640 (7.30)

2040 (9.07)

3040 (13.52)

3260 (14.50)

Refer to Standard Detail TS027

Chord Mil (GA)

28TSC (22)

33TSC (20)

43TSC (18)

54TSC (16)

TS1WTC3

Clip on One Face

550 (2.45)

Clip on Each Face

1640 (7.30)

2040 (9.07)

3040 (13.52)

4180 (18.60)

Refer to Standard Detail TS027

Chord Mil (GA)

28TSC (22)

33TSC (20)

43TSC (18)

54TSC (16)

TS6WTC5

Clip on One Face

550 (2.45)

Clip on Each Face

2460 (10.94)

3060 (13.61)

4560 (20.28)

5050 (22.46)

Refer to Standard Detail TS027A

Maximum Connection Reactions - Uplift

LBS (kN)

Chord Mil (GA)

28TSC (22)

33TSC (20)

43TSC (18)

54TSC (16)

TS1WTC5

Clip on One Face

550 (2.45)

Clip on Each Face

2460 (10.94)

3060 (13.61)

4560 (20.28)

6280 (27.93)

Refer to Standard Detail TS027A

Connections to Heavy Steel

Connections to CFS

Chord Mil (GA)

28TSC (22)

33TSC (20)

43TSC (18)

54TSC (16)

TS6WTC3

Clip on One Face

550 (2.45)

Clip on Each Face

1640 (7.30)

2040 (9.07)

3040 (13.52)

3260 (14.50)

Refer to Standard Detail TS027B

Chord Mil (GA)

28TSC (22)

33TSC (20)

43TSC (18)

54TSC (16)

TS1WTC3

Clip on One Face

550 (2.45)

Clip on Each Face

1640 (7.30)

2040 (9.07)

3040 (13.52)

4180 (18.60)

Refer to Standard Detail TS027B

Chord Mil (GA)

28TSC (22)

33TSC (20)

43TSC (18)

54TSC (16)

TS6WTC5

Clip on One Face

550 (2.45)

Clip on Each Face

2460 (10.94)

3060 (13.61)

4560 (20.28)

5050 (22.46)

Refer to Standard Detail TS027C

Chord Mil (GA)

28TSC (22)

33TSC (20)

43TSC (18)

54TSC (16)

TS1WTC5

Clip on One Face

550 (2.45)

Clip on Each Face

2460 (10.94)

3060 (13.61)

4560 (20.28)

6280 (27.93)

Refer to Standard Detail TS027C

1 2 3 4 56 7 8

5.08

CONNECTIONS / DETAILS

Fastened Connections to CFS Steel Bearings

Connections using TSUC Clips

Description

CFS trusses may be anchored to cold-formed

steel bearings using TrusSteel TSUC clips.

Several sizes of TSUC clips are available,

depending upon the required load transfer

capability.

Fasteners

These clips are attached to the truss and bearing

with #10 self-drilling tapping screws. Note that

the name for these screws is sometimes

abbreviated as SDS.

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of TSUC

clips, clip sizes, installation requirements and

lateral load capacities:

TS028

TS029

TSUC Clip attached to CFS bearing using #10 self-

drilling tapping screws

Mil - Grade

28 Mil - Grade 33

28 Mil - Grade 50

33 Mil - Grade 33

33 Mil - Grade 50

43 Mil - Grade 33

43 Mil - Grade 50

54 Mil - Grade 33

54 Mil - Grade 50

68 Mil - Grade 33

68 Mil - Grade 50

97 Mil - Grade 33

97 Mil - Grade 50

Wall Top Plate

Minimum Thickness

Refer to Standard Detail TS028

Maximum Connection Reactions - Uplift

TSUC3 Clips to CFS Bearing

IN (mm)

0.0269 (0.68)

0.0328 (0.83)

0.0428 (1.09)

0.0538 (1.37)

0.0677 (1.72)

0.0966 (2.45)

Clip On

One Face

LBS (kN)

170 (0.76)

250 (1.11)

210 (0.93)

310 (1.38)

280 (1.25)

400 (1.78)

350 (1.56)

400 (1.78)

Clip On

Each Face

LBS (kN)

410 (1.82)

590 (2.62)

500 (2.22)

730 (3.25)

650 (2.89)

950 (4.23)

830 (3.69)

1190 (5.29)

1040 (4.63)

1230 (5.47)

Mil - Grade

28 Mil - Grade 33

28 Mil - Grade 50

33 Mil - Grade 33

33 Mil - Grade 50

43 Mil - Grade 33

43 Mil - Grade 50

54 Mil - Grade 33

54 Mil - Grade 50

68 Mil - Grade 33

68 Mil - Grade 50

97 Mil - Grade 33

97 Mil - Grade 50

Wall Top Plate

Minimum Thickness

Refer to Standard Detail TS029

TSUC5 Clips to CFS Bearing

IN (mm)

0.0269 (0.68)

0.0328 (0.83)

0.0428 (1.09)

0.0538 (1.37)

0.0677 (1.72)

0.0966 (2.45)

Clip On

One Face

LBS (kN)

290 (1.29)

400 (1.78)

350 (1.56)

400 (1.78)

Clip On

Each Face

LBS (kN)

680 (3.02)

990 (4.40)

840 (3.74)

1210 (5.38)

1090 (4.85)

1580 (7.03)

1370 (6.09)

1980 (8.81)

1730 (7.70)

2050 (9.12)

1 2 3 4 56 7 8

5.09

CONNECTIONS / DETAILS

Connections using TSUC Clips Description

CFS trusses may be anchored to heavy steel

bearings by using TrusSteel TSUC clips. Several

sizes of TSUC clips are available, depending upon

the required load transfer capability.

Fasteners

These clips are attached to the truss with #10

self-drilling tapping screws. Clips are attached to

bearing with #12 or #14 screws, or pins.

TSUC5 Clip attached to red iron bearing. See Standard

Details for fastener placement.

Fastened Connections to Heavy Steel Bearings

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of TSUC

clips, clip sizes, installation requirements and

lateral load capacities:

TS039 pins into 3/16” to 1/2” steel

TS040 pins into 3/16”to 1/2” steel

TS047 screws into 1/8” to 1/2” steel

TS048 screws into 1/8” to 1/2” steel

TSUC5 Clip attached to concrete bearing with

Tapcon®fasteners.

Description

CFS trusses may be anchored to concrete

bearings by using TrusSteel TSUC clips. Several

sizes of TSUC clips are available, depending upon

the required load transfer capability.

Fasteners

These clips are attached to the truss with #10

self-drilling tapping screws, and can be attached

to the bearing with Tapcon®fasteners.

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of TSUC

clips, clip sizes, installation requirements and

lateral load capacities:

TS030

TS031

Fastened Connections to Concrete Bearings

Connections using TSUC Clips

Maximum Connection Reactions - Uplift

Clip

TSUC3

TSUC5

TSUC3

TSUC5

Steel Thickness

IN (mm)

3/16 (4.76)

1/4 (6.35) to

1/2 (12.70)

3/16 (4.76)

1/4 (6.35) to

1/2 (12.70)

1/8 (3.18) to

1/2 (12.70)

1/8 (3.18) to

1/2 (12.70)

Clip on One Face

LBS (kN)

400 (1.78)

Clip on Each Face

LBS (kN)

1230 (5.47)

2050 (9.12)

1230 (5.47)

2050 (9.12)

Standard

Detail

TS039

TS040

TS047

TS048

Maximum Connection Reactions - Uplift

Clip

TSUC3

Concrete Strength

PSI (MPa)

2000 (13.79)

3000 (20.68)

4000 (27.58)

5000 (34.47)

Clip on One Face

LBS (kN)

n/a

Clip on Each Face

LBS (kN)

520 (2.31)

570 (2.54)

660 (2.94)

740 (3.29)

Standard

Detail

TS030

TSUC5

2000 (13.79)

3000 (20.68)

4000 (27.58)

5000 (34.47)

400 (1.78)

520 (2.31)

570 (2.54)

660 (2.94)

740 (3.29)

TS031

1 2 3 4 56 7 8

5.10

CONNECTIONS / DETAILS

TSUC5 Clip attached to wood bearing with

wood screws.

Description

CFS trusses may be anchored to wood bearings

by using TrusSteel TSUC clips. Several sizes of

TSUC clips are available, depending upon the

required load transfer capability.

Fasteners

These clips are attached to the truss with #10

self-drilling tapping screws, and can be attached

to the bearing with wood screws.

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of TSUC

clips, clip sizes, installation requirements and

lateral load capacities:

TS032

TS033

Fastened Connections to Wood Bearings

Connections using TSUC Clips

Maximum Connection Reactions - Uplift

Clip

TSUC3

Wall Top Plate

Species

Spruce-Pine-Fir

Hem-Fir

Douglas Fir-Larch

Southern Pine

Clip on One Face

LBS (kN)

380 (1.69)

400 (1.78)

Clip on Each Face

LBS (kN)

910 (4.05)

960 (4.27)

1230 (5.47)

Standard

Detail

TS032

TSUC5

Spruce-Pine-Fir

Hem-Fir

Douglas Fir-Larch

Southern Pine

400 (1.78)

1520 (6.76)

1600 (7.12)

2050 (9.12)

TS033

1 2 3 4 56 7 8

5.11

CONNECTIONS / DETAILS

Connections using ITWBCG Hardware

ETAM Straps

Description

CFS trusses may be attached by ETAM straps

embedded into concrete beams. These straps are

attached to the truss with #10 self-drilling

tapping screws. Several sizes of ETAM straps are

available, depending upon the required load

transfer capability. See referred Standard Details

for lateral load capacities.

Fasteners

These straps are attached to the truss with #10

self-drilling tapping screws.

ETAM strap at truss heel or internal bearing

Embedded Connections to Concrete

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection of ETAM

Straps and installation requirements:

TS034

TS035

No. of Screws

per ETAM

TSC2.75

LBS (kN)

550 (2.45)

ETAM on One Face

TSC4.00

LBS (kN)

660 (2.94)

880 (3.91)

ETAM on Each Face

TSC2.75 & TSC4.00

LBS (kN)

1320 (5.87)

1760 (7.83)

ETAM

Straps into Concrete Bearing (Internal)

Refer to Standard Detail TS034

ETAMstrap at truss heel

Maximum Connection Reactions - Uplift

Top Chord

28TSC2.75

33TSC2.75

43TSC2.75

28TSC4.00

33TSC4.00

43TSC4.00

54TSC4.00

Mil (GA)

28 (22)

33 (20)

43 (18)

28 (22)

33 (20)

43 (18)

54 (16)

ETAM on One Face

LBS (kN)

530 (2.36)

550 (2.45)

510 (2.27)

660 (2.94)

900 (4.00)

ETAM on Each Face

LBS (kN)

1230 (5.47)

1530 (6.81)

1760 (7.83)

ETAM

Straps into Concrete Bearing (Heel)

Refer to Standard Detail TS035

Maximum Connection Reactions - Uplift

1 2 3 4 56 7 8

5.12

CONNECTIONS / DETAILS

ITWBCG

Part

GTH2

Single-Ply TrusSteel

Top Chord

TSC2.75 w/ Seat Plate

TSC4.00 w/ Seat Plate

Mil (GA)

Range

28-43 (22-18)

28-54 (22-16)

Capacity

LBS (kN)

4110 (18.28)

Standard

Detail

TS050

GTH2

28TSC2.75 w/o Seat Plate

33TSC2.75 w/o Seat Plate

43TSC2.75 w/o Seat Plate

28TSC4.00 w/o Seat Plate

33TSC4.00 w/o Seat Plate

43TSC4.00 w/o Seat Plate

54TSC4.00 w/o Seat Plate

28 (22)

33 (20)

43 (18)

28 (22)

33 (20)

43 (18)

54 (16)

870 (3.87)

1220 (5.43)

1270 (5.65)

810 (3.60)

1140 (5.07)

2100 (9.34)

2530 (11.25)

TS051

ITWBCG

Part

GTH2

GTH4

GTH2

Two-Ply TrusSteel

Top Chord

TSC2.75 w/ Seat Plate

TSC4.00 w/ Seat Plate

TSC2.75 w/o Seat Plate

Mil (GA)

Range

28-43 (22-18)

28-54 (22-16)

28-43 (22-18)

Capacity

LBS (kN)

5050 (22.46)

5290 (23.53)

1270 (5.65)

Standard

Detail

TS052

TS054

TS053

ITWBCG

Part

GTH3

Three-Ply TrusSteel

Top Chord

TSC2.75 w/ Seat Plate

Mil (GA)

Range

28-43 (22-18)

Capacity

LBS (kN)

6580 (29.27)

Standard

Detail

TS055

Connections using ITWBCG Hardware

GTH Connectors

Description

CFS trusses may be attached to concrete

bearings using GTH connectors. Several sizes of

GTH connectors are available, depending upon

the required load transfer capability.

Fasteners

These connectors are attached to the truss with

#10 self-drilling tapping screws and the

connectors are fastened to the concrete bearing

using threaded rods which are installed into the

concrete using an epoxy adhesive.

TrusSteel truss anchored to concrete bearing using

ITWBCG Hardware GTH-series connector and epoxy-

installed threaded rod.

Embedded Connections to Concrete

Reference Standard Details

Please refer to the Standard Details shown in the

chart below for information regarding the

selection of GTH connectors, sizes and

installation requirements:

TS050

TS051

TS052

TS053

TS054

TS055

Maximum Connection Reactions - Uplift

1 2 3 4 56 7 8

5.13

CONNECTIONS / DETAILS

Connections using ITWCBCG Hardware

HT2.5A Connectors

Description

CFS trusses in a piggyback configuration may be

anchored to the top chords of base trusses using

TrusSteel TTC7 clips or ITWBCG Hardware FAL

Framing Anchors.

Fasteners

These connections are made with #10 self-

drilling tapping screws.

Fastened Connections for Piggybacks

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection and

installation requirements:

TS003

TS003A

TS003B

Connections using ITWBCG Hardware

HT2.5A Connectors

Description

CFS trusses in a valley configuration may be

attached to the top chords of TrusSteel trusses

using ITWBCG Hardware HT2.5A connectors.

Fasteners

These connections are made with #10 self-

drilling tapping screws.

Reference Standard Details

Please refer to these Standard Details for

information regarding the selection and

installation requirements:

TS026 as shown at left

TS026A to metal deck

TS026B to wood structural panels

Fastened Connections for Valley Trusses

Truss to truss - refer to TS026

Truss to wood structural panels. - refer to TS026B

NOTES

1 2 3 4 5 67 8

6.01

TRUSS FABRICATION / QUALITY

Overview

Site-Fabricated vs Shop-Fabricated

CFS Trusses

Prior to the emergence of pre-fabricated CFS

truss systems, contractors built most CFS

trusses on the jobsite using c-stud material.

While many contractors were more than capable

of building a CFS truss, jobsite issues such as the

availability of flat terrain for truss fabrication,

exposure to the elements, handling issues and

the availability of experienced fabrication

personnel often challenged the completion of

quality trusses in a timely manner. Any one of

these issues could lead to delays in truss

fabrication and so to delays in one of the most

critical phases of construction: the drying-in of

the building.

Overall, the construction industry welcomed the

advent of pre-engineered, pre-fabricated CFS

trusses in the same way as they welcomed the

advent of wood trusses and bar joists. These

building components, assembled in a shop in

advance of need and properly stored until ready

for delivery, removed a burdensome jobsite task

from the contractors’ busy schedule and

delivered a product that was generally high in

quality.

The Advantages of Quality Control

TrusSteel Authorized Fabricators assemble

TrusSteel CFS trusses in a truss shop

environment. The reason is quality control. In-

shop quality control assures that each truss is:

• assembled to dimensional tolerances (to

assure a good fit at the jobsite),

• assembled in strict accordance with the

materials and fastening methods described on

the shop drawings (to assure specified

structural performance),

• handled, stored and eventually shipped in a

manner to eliminate damage.

TrusSteel supports the efforts of industry

organizations, such as SBC Colf_formed Steel

Council in the implementation of quality

assurance standards.

The Advantages of Trained Assemblers

For a truss package to fit and perform according

to dimensional and structural specifications, the

truss fabricator must assemble each individual

truss to exacting standards. The fabricator must

use trained sawyers and proper cutting and

jigging equipment to ensure the trusses will have

straight chords, tight joints and to maintain

consistency of pattern from one truss to the next.

Trained assemblers should install fasteners to

ensure the accuracy of each internal connection

and to avoid commonplace problems such as the

over-torquing of fasteners.

The Advantages of Proper Equipment

TrusSteel is the only proprietary CFS truss

technology supplier that offers a complete line of

truss fabrication equipment. Drawing upon

Alpine’s more than forty years of experience in

wood truss fabrication equipment, TrusSteel

offers a complete line of cutting, measuring,

jigging and handling systems.

TrusSteel provides a line of band saws for

materials cutting that are safe, quiet and

accurate. By teaming these saws with an

automatic or manual measuring system, a

sawyer can greatly improve his output while

maintaining strict dimensional standards.

Sophisticated full-automatic jigging systems,

such as the AutoSet C, allow the electronic

transfer of truss profile data directly to the jig

table. Semi-automatic jigging systems, such as

the AutoSet, and manual jigging tables can allow

any truss shop to make quick and accurate

setups.

Truss ejector systems, roller beds and stacking

systems can make truss handling quick, simple

and safe. Specialty presses, metalworkers and

swagers expedite the assembling of the most

complicated trusses and complete this

comprehensive product line.

TRUSS FABRICATION / QUALITY

Overview

1 2 3 4 5 67 8

6.02

Truss Size Limitations

Handling and shipping issues limit the size of

individual CFS trusses. Smaller trusses can be

joined in the field (field splicing) to create larger

trusses. Practical limits for handling and shipping

will vary depending upon the capabilities of the

individual truss shop and the distance to the

jobsite. Contact your local TrusSteel Authorized

Fabricator for specific information.

The Advantages of TrusSteel

The advantages of TrusSteel in the fabrication

process translate into advantages to the

designer, contractor and owner. The fact that the

proprietary shape is easy and stable to handle

makes for faster assembly just as it makes for

stronger, lighter, stiffer trusses in the field. Rolled

chord edges and closed tube webs make for

safer handling in both shop and field. Proprietary,

color-coded fasteners make for quick, accurate

assembly just as they make it easier for field

inspection. The in-plane assemblies of

components in the trusses allow the creation of

tight bundles that stack and unstack efficiently at

the shop and jobsite and are more resistant to

handling damage.

The Authorized Fabricator Advantage

Each TrusSteel Authorized Fabricator is an

independently owned and operated

local/regional truss fabrication shop. Authorized

Fabricators market and service truss projects in

their own region, backed by the forty continuous

years of truss experience. Taken together, the

nationwide network of TrusSteel Authorized

Fabricators forms a vast array of truss and

framing knowledge at the disposal of the

designer and installer.

Truss Jigging Systems

Alpine Equipment’s Steel AutoSet CTM and Steel

AutoSetTM Jigging Systems brings accuracy and

automation to the steel truss fabrication shop.

When the Steel AutoSet C is used with the Alpine

steelVIEW software, truss jig setups are created

automatically as the truss is designed. Setups

are then transferred to the shop floor, where a

single shop worker can adjust the jig rail stops

within seconds (using the AutoSet C touch-

screen input computer terminal).

Truss fabrication setups on the AutoSet and

AutoSet C are fast, accurate, and repeatable. No

special tools are required to operate the jigging

systems. Setups on the AutoSet System are

made in minutes by a single worker using a

driver gun and a digital counter.

Both the Steel AutoSet C and the Steel AutoSet

Jigging Systems can be used for the fabrication

of all types of cold-formed components.

Truss Handling Systems

An integral truss ejector system speeds the

removal of completed trusses from the jig. And,

because the ejectors do the lifting, shop workers

are subject to less strain and fatigue. Less

fatigue means workers remain more productive.

Conveyor runs, truss stackers and other handling

equipment are also available from TrusSteel.

1 2 3 4 5 6 78

7.01

INSTALLATION / BRACING

Site Conditions & Safety

Safety is no accident. Safe work habits and a

safe work environment are the responsibility of

everyone on the job site. All injuries can be

prevented through appropriate training,

awareness and actions. Proper safety

equipment, such as glasses, hard hats, shoes

and harnesses, must be used consistently and

correctly.

Site conditions

Proper site conditions for the installation of

trusses are primarily the responsibility of the

owner’s representative for construction. Unless

otherwise designated, that representative is

usually the general contractor or the construction

manager.

The American Iron and Steel Institute has

published guidelines for establishing good site

practices. The following list of responsibilities is

taken from the AISI/S202. Designations shown in

parentheses refer to the corresponding sections

of that publication.

(F2.1) The installer of CFS trusses shall be

permitted to use the most efficient and

economical method and sequence of installation

or assembly available consistent with the

contract documents. When the owner contracts

separately with a component manufacturer and

installer, the owner is responsible for

coordinating work between contractors.

(F2.2) The installer shall examine areas and

conditions under which framing materials are to

be installed. Work shall not proceed until

unsatisfactory conditions have been corrected by

those responsible.

(F2.3) The owner’s representative for

construction shall provide and maintain

adequate access necessary for equipment and

framing materials to be installed. The owner’s

representative for construction shall provide the

installer with level, convenient, and adequate

space to safely use the necessary equipment

and install the framing materials.

(F2.4) The contractor shall coordinate setting

drawings, dimensional problems, compatibility of

various trades and / or installation.

Bracing

All temporary installation bracing, permanent

bracing and bridging must be fully and correctly

installed prior to the application of any loads,

including any temporary loads resulting from

construction procedures. Refer to Section 7 in

this Manual for more information.

Installation Tolerances

Structural members and component assemblies

shall be installed in accordance with the

tolerances prescribed in the AISI/S200: North

American Standard for Cold-Formed Steel

Framing - General Provisions. Trusses shall be

installed in accordance with the additional

requirements of the AISI /S214: North American

Standard for Cold-Formed Steel Framing - Truss

Design.

Field Modifications and Repairs

Removal, cutting or alteration of any truss chord,

web or bracing member in the field is prohibited,

unless approved in advance, in writing, by the

truss designer (Truss Component Manufacturer).

Field Quality Control

Trusses shall be installed in accordance with the

requirements of the AISI/S214: North American

Standard for Cold-Formed Steel Framing - Truss

Design. and with any standards and

requirements set forth in the construction

documents. The owner's representative for

construction will provide inspection service to

inspect field connections.

INSTALLATION / BRACING

Handling & Storage

1 2 3 4 5 6 78

7.02

Material Receiving

Inspect all CFS materials immediately upon

arrival. Report all damaged or missing material

immediately to vendor and note all damage on

carrier's shipping documents.

Material Handling

Finished CFS trusses are usually banded with

steel strapping in conveniently sized bundles.

The strapping helps maintain truss alignment

and the bundle strength minimizes damage

during delivery and storage. WARNING: Exercise

care when removing strapping to prevent injury.

Throughout all phases of construction, care must

be taken to avoid excessive lateral bending of the

trusses which can cause joint and member

damage.

If possible, CFS trusses should be unloaded on

relatively smooth ground. They should not be

unloaded on rough terrain that would cause

undue lateral strain resulting in distortion of the

truss joints. Rough terrain can also cause

damage to overhangs, soffit returns and other

parts of the truss.

Always lift long pieces of material from more

than one lift point to avoid crimping. Take care

when banding; do not crimp or bend material. Do

not store other materials on top of CFS materials.

Material Storage

Formed CFS components made of galvanized

steel material shall be stored in a low moisture

environment. Under no circumstances should

stored material be allowed to become wet. When

stored in bundles, materials shall be stored at an

incline to promote the drainage of any moisture

and to avoid moisture build-up in and on the

parts.

Storage area shall have good ventilation. Areas

that have poor ventilation, and that have the

potential for trapping moist air in rising

temperatures, can create a ‘hot house’ effect

that may cause condensation between the layers

of rolled or bundled material. This trapped

condensation can have the same effect on stored

material as exposing it to direct moisture. For

long-term storage, inspect bundled materials

regularly to assure that moisture has not

penetrated the bundle.

Storage environments shall be ventilated to avoid

temperature differentials in excess of 20ºF

between the stored material and the ambient

temperature of the storage. Environments that

allow temperature differentials in excess of 20ºF

can promote moisture condensation on

materials.

Cold steel materials shall be allowed to warm

properly before storage. The rapid warming of

incoming materials (when moved from a cool

environment to a warm environment) can create

condensation. If incoming galvanized steel feels

cold to the touch, allow it to warm slowly in a

cool indoor area away from drafts. When the

steel has warmed it may be transferred to a

proper storage area.

If trusses are stored in the vertical position, they

should be staked on both sides of the bundle to

prevent toppling and personal injury.

These storage instructions must be followed to

avoid chalking on any galvanized materials

(truss, stud, track, etc.). Chalking is created by

the invasion of moisture between two zinc

coated surfaces that are not allowed to dry in an

environment having adequate air flow. The

chalking is created through a chemical reaction

between the two surfaces when they are stored

in an oxygen deprived atmosphere.

TrusSteel trusses are often light enough for two

men to unstack and stage.

Horizontal storage of trusses.

Vertical storage using a rack or stand. Always

stake trusses to prevent toppling.

1 2 3 4 5 6 78

7.03

INSTALLATION / BRACING

Lifting & Staging

Proper Lifting of CFS Trusses

Trusses may be installed manually, by crane, or

by forklift, depending on truss size, wall height

and job conditions. Individual trusses should

always be carried vertically to avoid lateral strain

and damage to joints and members.

Trusses installed manually are slid into position

over the sidewall and rotated into position using

poles. The longer the span, the more workers

needed to avoid excessive lateral strain on the

trusses. Trusses should be supported at joints

and the peak while being raised.

Large trusses should be installed by a crane or

forklift employing chokers, slings, spreader bars

and strong-backs to prevent lateral bending.

Trusses may be lifted singly, in banded groups, or

in pre-assembled groups or rafts.

Tag lines should always be used to control

movement of trusses during lifting and

placement. Workers should always use all

appropriate safety equipment.

Storage of Materials During Installation

Care must be taken, after truss installation, not to

overload trusses with the storage of other

building materials. Under no circumstances

should any materials be stored on top of

unbraced trusses!

Reference Document

Refer to the CFSC Cold-Formed Steel Building

Component Safety Information document

CFSBCSI before handling or installing trusses.

This document is available from the CFSC at

www.cfsc.sbcindustry.com/cfsbsci.php.

Lift shown using a spreader bar to distribute the

load. Tag lines must be used during lifting.

Lift shown using a spreader bar to distribute the

load. Tag lines must be used during lifting.

Lift shown using a strongback to distribute the

load. Tag lines must be used during lifting.

WARNING: Exercise care when removing

strapping to prevent injury.

This installer is using a heavy steel truss as a

strongback.

1 2 3 4 5 6 78

7.04

INSTALLATION / BRACING

Bracing

Permanent Bracing

Permanent bracing typically includes continuous

lateral bracing (CLB), diagonal bracing, bridging

and blocking at the heels and ends of the

trusses. This bracing functions to strengthen and

stabilize the truss chords and webs which may

be particularly long or highly stressed. The

required locations of the continuous lateral

bracing are typically called out on the shop

drawings supplied by the truss engineering

company. These lateral braces must be stabilized

at regular intervals with diagonal bracing. This

extremely important bracing system creates the

continuous path through which all loads applied

to the roof are transferred from the truss system

into the walls and eventually to the ground.

Due to the component-centered nature of our

fast track building process, permanent bracing

design is not supplied by the wall panelizer or

designer, or by the truss fabricator, because

neither party controls the design process of the

other component. To bridge this gap in the

information process, a number of engineering

firms are beginning to provide permanent

bracing design based on their review of the wall

and truss layouts supplied by separate parties.

Bracing and Structural Performance

The structural performance of a frame building

depends on continuous paths for all loads to be

transferred to the ground. In the specific instance

of pre-engineered trusses, there are two types of

necessary bracing which are sometimes

confused: construction (temporary) and

permanent bracing. Each is important to the

construction process and to the structural

integrity of the building.

Construction (Temporary) Bracing

This is the proper bracing of the trusses during

the installation phase of the structure. Much like

walls are braced until the completion of the

framing process, when trusses are placed on the

plate line, they must be braced to hold them

safely and securely in place, and to resist

environmental influences such as wind gusts

during the framing process. Construction bracing

guidelines are available through truss industry

documents for truss spans up to 60 ft. For spans

over 60 ft. a professional engineer should be

consulted for the construction bracing plan.

Top chord diagonal bracing

Top chord lateral bracing

Ground bracing for first truss

Temporary Bracing for Installation

Examples of permanent bracing at truss heels,

using cross-bracing (top) and trusses as

blocking (bottom)

1 2 3 4 5 6 78

7.05

INSTALLATION / BRACING

Rafting

What is rafting?

Rafting is a process where the installer uses

complete trusses to assemble an entire roof, or

section of a roof, on the ground and then lifts the

completed assembly onto the building structure.

The size of rafted sections is based on available

space on-site, lift capacity of the available crane,

or unique footprint of the roof system.

Why use rafting?

On suitable projects, rafting allows most of the

roof framing and decking to be assembled on the

ground, minimizing or eliminating the need for

multiple lifts, scaffolding and fall protection

systems. Less lifts means less crane time, which

can translate into big savings on crane costs. On-

ground assembly of entire roof sections,

including permanent truss bracing, roof decks

and mechanical systems, can save significant

labor time and can allow the simultaneous

construction of walls and roof systems.

What are the special considerations for

rafting?

The design of the roof assembly to be rafted

should consider the effect of an alternate load

path, where the weight of the assembly is

transferred through the lifting cables (or straps)

to the ground at pick points instead of through

the truss bearings. The number and location of

pick points for rafting should be determined with

attention to the following factors:

• total weight of the assembly,

• weight distribution in the assembly,

• truss configuration,

• crane capacity.

In addition to design analysis for conventional

roof loads, rafted trusses must also be analyzed

for a case where the supports are at the pick

points. In some instances, the permanent

bearing members for the trusses (tube steel or

I-beam, for example) could be included as a part

of the assembly on the ground, and the entire

assembly could be lifted from pick points located

on the bearing members. Adequate bracing of

trusses is needed for the stability of the roof

system. Most of the roof decking, and almost all

of the required truss permanent bracing for the

webs and bottom chord, could be installed prior

to rafting.

Why raft with TrusSteel?

TrusSteel trusses are light in weight (up to one-

half the weight of trusses made from wood or

"C" channel materials). Substantial roof sections

can be assembled on the ground and then lifted

with an average crane. With the exceptional

lateral stability (stiffness) of TrusSteel trusses,

roof assemblies can be built that will survive a lift

without introducing significant extra bracing.

How do I get an engineered raft?

Rafts of trusses, no matter the brand or

type, must be engineered so that they will

lift safely and without causing damage to

the trusses. The project Engineer of

Record may perform this design service.

Specialty engineering firms, such as BBD

Engineering and Design, LLC, are

available to perform these design services

on a consulting basis.

1 2 3 4 5 6 7 8

8.01

REFERENCES/RESOURCES

These organizations and materials can

provide resources for the design, use and

installation of CFS framing as well as an

overview of good construction practices.

Please contact the publisher or group

directly for further information.

Industry Resources

American Institute of Architects (AIA)

202-626-7300 www.aia.org

Locate architects and find information on the

profession, contract documents and more.

American Institute of Steel Construction

(AISC)

312-670-2400 www.aisc.org

American Iron and Steel Institute (AISI)

202-452-7100 www.steel.org

AIS S100-07: North American Specification for

the Design of Cold-Formed Steel Structural

Members; American Iron and Steel Institute;

2007 Edition with Supplement 2

AISI-S200-07:

AISI North American

Standard for

Cold-Formed Steel Framing - General Provisions;

2007 Edition.

AISI-S202-11:

AISI Code of Standard Practice

for

Cold-Formed Steel Structural Framing; 2011

Edition.

AISI-S214-07:

AISI Norh American

Standard for

Cold-Formed Steel Framing - Truss Design, 2007

Edition.

American National Standards Institute (ANSI)

212-642-4900 www.ansi.org

Administers and coordinates U.S. voluntary

standards.

American Society of Civil Engineers (ASCE)

800-548-2723 www.asce.org

Minimum Design Loads for Buildings And Other

Structures, ASCE 7-10

Structural Engineering Institute

STRUCTURE magazine

American Society for Testing and Materials

(ASTM)

610-832-9585 www.astm.org

ASTM E-119 - Test Methods for Fire Tests for

Building Construction and Materials

ASTM A 370-06 - Standard Test Methods and

Definitions for Mechanical Testing of Steel

Products.

ASTM A 500-03a - Standard Specification for

Cold-Formed Welded and Seamless Carbon Steel

Structural Tubing in Rounds and Shapes.

ASTM A 653-06a - Standard Specification for

Steel Sheet, Zinc-Coated (Galvanized) or Zinc-

Iron Alloy-Coated (Galvannealed) by the Hot-Dip

Process.

Association of Crane & Rigging Professionals

800-690-3921 www.acrp.net

Gain expertise in lifting and handling building

materials.

Association of the Wall and Ceiling Industry

703-534-8300 www.awci.org

AWCI-SFA Steel Framing Education Program

AWCI Construction Dimension magazine

AWCI bookstore

Center for Cold-Formed Steel Structures

(CCFSS)

573-341-4471 http://campus.umr.edu/ccfss/

CCFSS Technical Bulletins

CCFSS Newsletter

Educational seminars

Construction Specifications Institute (CSI)

800-689-2900 www.csinet.org

MasterFormat 2004

Construction Specifier magazine

National CAD Standard

Design-Build Institute of America (DBIA)

202-682-0110 www.dbia.org

DBIA bookstore

Numerous educational resources

Gypsum Association

202-289-5440 www.gypsum.org

Fire Resistance Design Manual, GA-600

International Code Council (ICC)

888-422-7233 www.iccsafe.org

The International Building Code

ICC-ES Evaluation Service

www.icc-es.org

Cold-Formed Steel Engineers Institute (CFSEI)

202-263-4488 www.cfsei.org

CFSEI 551d - Design Guide: Construction Bracing

of Cold-Formed Steel Trusses; September 2002.

CFSEI 551e - Design Guide: Permanent Bracing

of Cold-Formed Steel Trusses; February 1998.

CFSEI 551f -

Specifying Pre-Engineered Cold-

Formed Steel Floor and Roof Trusses

; October

1998.

Newsletters

Research Notes

Occupational Safety and Health

Administration (OSHA)

Directorate of Construction

202-693-2020 www.osha.gov

Safety regulations and procedures

The Steel Framing Alliance

202-785-2022

www.steelframingalliance.com

Various technical and marketing documents

Training for steel framers

Metal Construction Association

847-375-4718 www.metalconstruction.org

Metalcon Show

SBCA Cold-formed Steel Truss Council

(CFSC)

608-274-4849 www.cfsc.scbindustry.com

Truss labels

Truss educational programs

Quality program

CFSBCSI document

Steel Deck Institute (SDI)

847-458-4647 www.sdi.org

Diaphragm Design Manual

Steel Recycling Institute (SRI)

800-937-1226 www.recycle-steel.org

Steel Takes LEED with Recycled Content°®

Underwriters Laboratories (UL)

877-854-3577 www.ul.com

UL Fire Resistance Directory

U.S. Green Building Council (USGBC)

202-828-7422 www.usgbc.org

Information on the LEED program

REFERENCES/RESOURCES

Glossary

1 2 3 4 5 6 7 8

8.02

Accepted Engineering Practice An engineering

approach that conforms to accepted principles,

tests, technical standards, and sound judgment.

ASD (Allowable Strength Design) Method of

proportioning structural components such that

the allowable strength equals or exceeds the

required strength of the component under the

action of the ASD load combinations.

ASD Load Combination Load combination in the

applicable building code intended for allowable

strength design (allowable stress design).

Allowable Strength* Nominal strength divided

by the safety factor, Rn/Ω.

Applicable Building Code Building code under

which the structure is designed.

Available Strength* Design strength or

allowable strength as appropriate.

Approved Approval by a building official, code

official, design professional, or authority with

jurisdiction.

Axial Force The number of pounds of tension or

compression in a truss member acting parallel to

the length of the member resulting from a load

applied to the truss.

Base Metal Thickness The thickness of bare

steel exclusive of all coatings.

Bearing Structural support of a truss, usually

walls, beams, concrete slabs and hangers.

Bending Moment A measure of the amount of

bending in a member due to forces acting

perpendicular to the member.

Blocking C-shaped, track, brake shape, or flat

strap material attached to structural members,

flat strap, or sheathing panels to transfer shear

forces.

Bottom Chord A horizontal (or inclined in a

scissor truss) member that establishes the lower

edge of the truss, usually carrying combined

tension and bending stresses.

Braced Frame An essentially vertical truss

system that provides resistance to lateral loads

and provides stability for the structural system.

Bracing Structural elements that are installed to

provide restraint or support (or both) to other

framing members so that the complete assembly

forms a stable structure.

Bridging Cross-bracing or blocking placed

between joists to provide lateral support.

Buckling A kink, wrinkle, bulge, or other loss in

the original shape of a member due to

compression, bending, bearing, or shear loads.

Building Designer Also referred to as design

professional and registered building designer is

an individual or organization responsible for the

overall building design in accordance with the

statutes and regulations governing the

professional registration and certification of

architects or engineers of the jurisdiction where

the building will be located.

Camber An upward vertical displacement built

into a truss, usually to offset deflection due to

dead load.

Cantilever The part of a structural member that

extends beyond its support.

Chord Member A structural member that forms

the top or bottom component of a truss.

Clear Span Horizontal distance between interior

edges of supports.

Cold-Formed Sheet Steel Sheet steel or strip

that is formed by (1) press-braking blanks

sheared from sheets or cut length of coils or

plates, or by (2) continuous roll forming of cold-

or hot-rolled coils of sheet steel; both forming

operations are performed at ambient room

temperature, that is, without the addition of heat

such as would be required for hot forming.

Cold-Formed Steel Structural Member Shape

manufactured by press-braking blanks sheared

from sheets, cut lengths of coils or plates, or by

roll forming cold- or hot-rolled coils or sheets;

both forming operations being performed at

ambient room temperature, that is, without

manifest addition of heat such as would be

required for hot forming.

Collateral Load The weight of any non-moving

equipment or material, such as ceilings,

electrical or mechanical equipment, sprinkler

systems, plumbing, or ceilings.

Combined Stress The combination of axial and

bending stresses or shear and bending stresses

acting on a member simultaneously. These

stresses typically occur in both top and bottom

chords.

Concentrated Load A load, in addition to

uniform design loads, applied at a specific point.

Examples include cranes, hoists, HVAC

equipment and sprinkler pipes.

Compression A force caused by loads being

placed on a member that causes a squeezing or

shortening effect of the member as in the top

chord of a truss when load is applied.

Component Assembly A fabricated

assemblage of cold-formed steel structural

members that is manufactured by the

component manufacturer, which may also

include structural steel framing, sheathing,

insulation or other products.

Component Design Drawings The written,

graphic and pictorial definition of an individual

component assembly, which includes

engineering design data.

Component Designer The individual or

organization responsible for the engineering

design of component assemblies. See Truss

Designer.

Component Manufacturer The individual or

organization responsible for the manufacturing

of component assemblies for the project. See

Truss Manufacturer.

Component Placement Diagram The

illustration supplied by the component

manufacturer identifying the location assumed

for each of the component assemblies which

references each individually designated

component design drawing.

1 2 3 4 5 6 7 8

8.03

Glossary

Connection Combination of structural elements

and joints used to transmit forces between two

or more members.

Construction Manager The individual or

organization designated by the owner to issue

contracts for the construction of the project and

to purchase products.

Continuous Lateral Bracing A member placed

and connected at right angles to a chord or web

to prevent buckling. Required on some chords

and webs, depending on their length and the

forces in the member.

Contract Documents The documents, including,

but not limited to, plans and specifications,

which define the responsibilities of the parties

involved in bidding, purchasing, designing,

supplying, and installing cold-formed steel

framing.

Contractor The individual or organization that is

contracted to assume full responsibility for the

construction of the structure.

Cricket A portion of a roof where it is built up for

the purpose of draining water towards a desired

drainage point.

C-Shape A cold-formed steel shape used for

structural and nonstructural framing members

consisting of a web, two flanges, and two lips

(edge stiffeners). The name comes from the

member’s C-shaped cross-sectional

configuration. It is also called a “C-section.” Web

depth measurements are taken to the outside of

the flanges. Flange width measurements also

use outside dimensions.

Dead Loads Dead loads are the weight of the

walls, partitions, framing, floors, ceilings, roofs,

and all other permanent construction entering

into and becoming a part of a building.

Deflection Movement of a structural member,

like a truss in place, due to the application of

loads. Deflection is usually downward, but

trusses may deflect upward or horizontally

depending on loads and bearings.

Design Load Applied load determined in

accordance with either LRFD load combinations

or ASD load combinations, whichever is

applicable.

Design Strength* Resistance factor multiplied

by the nominal strength: ϕ x Rn.

Design Professional An individual who is

registered or licensed to practice his or her

respective profession as defined by the statutory

requirements of the state in which the project is

to be constructed.

Design Thickness The steel thickness used in

design which is equal to the minimum base

metal thickness divided by 0.95.

Diaphragm Roof, floor or other membrane or

bracing system that transfers in-plane forces to

the lateral force resisting system.

Double Shear Allowing a force to be distributed

through two planes rather than one for increased

strength.

Double ShearTM Fastener Patented TrusSteel

fastener that allows the fabrication of trusses

without flipping in the jig. Double shear action of

these fasteners add stability to trusses.

Drag Strut Typically a horizontal member, such

as a truss or beam, which transfers shear from a

diaphragm to a shearwall.

Eave Overhang The horizontal projection of the

roof measured from the outside face of the

exterior wall framing to the outside edge of the

roof.

Epicenter The part of the earth’s surface directly

above the focus of an earthquake.

Flange That portion of a framing member or

track that is perpendicular to the web.

Factored Load Product of a load factor and the

nominal load.

Flat Strap Sheet steel cut to a specified width

without any bends and typically used for bracing

and transferring loads by tension.

Flashing Pieces of cold-formed steel that are

used to make watertight the openings or the

seams in a roof system.

Flexural-Torsional Buckling Buckling mode in

which a compression member bends and twists

simultaneously without change in cross-

sectional shape.

Floor Joist A horizontal structural framing

member that supports floor loads and

superimposed vertical loads.

Foundation The structural elements through

which the load of a structure is transmitted to

earth.

Gable End A vertical surface formed at the end

of a roof ridge down towards the eave.

Gauge A unit of measurement traditionally used

to describe the nominal thickness of steel. The

lower the gauge the greater the thickness.

Girt Horizontal structural member that supports

wall panels and is primarily subjected to bending

under horizontal loads, such as wind load.

Grade The finished ground level adjoining the

building at exterior walls.

Ground Snow Load Measured load on the

ground due to snow accumulation developed

from a statistical analysis of weather records

expected to be exceeded once every 50 years at

a given site.

Gusset Plate A structural member used to

facilitate the connection of truss chord or web

members at a heel, ridge, or panel point.

Hat-Shape A singly-symmetric shape consisting

of at least two vertical webs and a horizontal

stiffened flange which is used as a chord

member in a truss.

ASTM C955 Color Codes for CFS Steel

Color mils GA

White 33 20

Yellow 43 18

Green 54 16

Orange 68 14

Red 97 12

REFERENCES/RESOURCES

1 2 3 4 5 6 7 8

8.04

REFERENCES/RESOURCES

Glossary

Heel Point on a truss at which the top chord and

bottom chord intersect at the end of a truss with

a sloping top chord.

Hip-Set A sloped roof surface that extends from

a roof ridge towards the eave.

Installation Drawings Drawings that show the

location and installation of the cold-formed steel

structural framing.

Installer Party responsible for the installation of

cold-formed steel products.

Joint Area where two or more ends, surfaces, or

edges are attached. Categorized by type of

fastener or weld used and the method of force

transfer.

Lateral Forces Non-gravity forces acting on a

building such as wind and seismic.

Lateral Force Resisting System The structural

elements and connections required to resist

racking and overturning due to wind and/or

seismic forces imposed upon the structure in

accordance with the applicable building code.

Lateral Load A horizontal force created by wind

or earthquake that acts on a structure or its

components.

Level Return Filler placed horizontally from the

end of an overhang back to the bearing support

to form soffit framing.

Live Loads Live loads are transient and

sustained loads usually created by people and

furnishing, respectively.

Load Force or other action that results from the

weight of building materials, occupants and their

possessions, environmental effects, differential

movement, or restrained dimensional changes.

Load Effect Forces, stresses, and deformations

produced in a structural component by the

applied loads.

Load Factor Factor that accounts for deviations

of the nominal load from the actual load, for

uncertainties in the analysis that transforms the

load into a load effect, and for the probability that

more than one extreme load will occur

simultaneously.

LRFD (Load and Resistance Factor Design)

Method of proportioning structural components

such that the design strength equals or exceeds

the required strength of the component under

the action of the LRFD load combinations.

LRFD Load Combination Load combination in

the applicable building code intended for

strength design (Load and Resistance Factor

Design).

Material Supplier An individual or entity

responsible for furnishing framing materials for

the project.

Mil A unit of measurement used in measuring

the thickness of thin steel elements. One mil

equals 1/1000 of an inch (e.g., 33 mil = 0.033

inch).

Moment Frame Framing system that provides

resistance to lateral loads and provides stability

to the structural system primarily by shear and

flexure of the framing members and their

connections.

Multi-Node Analysis A truss analysis

methodology when each individual web member

at a joint is modeled with its own node.

Multiple Span The span made by a continuous

member with intermediate supports.

Nominal Load Magnitude of the load specified

by the applicable building code.

Nominal Strength* Strength of a structure or

component (without the resistance factor or

safety factor applied) to resist the load effects, as

determined in accordance with a Specification or

Standard.

Overhang The extension of the top or bottom

chord of a truss beyond the bearing support.

Panel In a truss, the chord segment defined by

two successive joints.

Panel Length The centerline distance between

joints measured horizontally.

Panel Point The connection region between a

web and chord member.

Peak Point on a truss where two sloped chords

meet.

Permanent

Load

Load in which variations over

time are rare or of small magnitude. All other

loads are variable loads.

Piggyback Truss. A truss supported directly on

top of another truss. Trusses are piggybacked

due to height restrictions in fabrication and

delivery.

Pitch See Slope.

Pitch Break A location around the perimeter of

a truss where the chord changes pitch.

Plans Drawings prepared by the design

professional for the owner of the project. These

drawings include but are not limited to floor

plans, framing plans, elevations, sections, details

and schedules as necessary to define the desired

construction.

Purlin Horizontal structural member that

supports roof deck and is primarily subjected to

bending under vertical loads such as snow, wind

or dead loads. (May also brace the top chord of

trusses in certain applications, resulting in an

applied axial force).

Rake The inclined edge of a roof.

Rake Overhang The horizontal projection of the

roof measured from the outside face of a gable

endwall to the outside edge of the roof.

Rational Engineering Analysis Analysis based

on theory that is appropriate for the situation,

relevant test data if available, and sound

engineering judgment.

Reaction Forces acting on a truss through its

supports which are equal (but opposite) to the

sum of the dead and live loads.

Release for Construction The release by the

owner’s representative, permitting the

component manufacturer and/or installer to

commence work under the contract, including

1 2 3 4 5 6 7 8

8.05

Glossary

ordering framing material and preparing

installation drawings.

Required Strength* Forces, stresses, and

deformations produced in a structural

component, determined by either structural

analysis, for the LRFD or ASD load combinations,

as appropriate, or as specified by Specification or

Standard.

Resistance Factor, ΨFactor that accounts for

unavoidable deviations of the nominal strength

from the actual strength and for the manner and

consequences of failure.

Ridge The line formed by the joining of the top

edges of two sloping roof surfaces.

Safety Factor, ΩFactor that accounts for

deviations of the actual strength from the

nominal strength, deviations of the actual load

from the nominal load, uncertainties in the

analysis that transforms the load into a load

effect and for the manner and consequences of

failure.

Secondary Bending The bending stress in a

member caused by the deflection of the whole

truss.

Service Load Load under which serviceability

limit states are evaluated.

Shear Wall Wall that provides resistance to

lateral loads in the plane of the wall and provides

stability for the structural system.

Shop Drawings Drawings for the production of

individual component assemblies for the project.

Slope (Pitch) The inches in vertical rise in 12

inches of horizontal run for inclined members,

generally expressed as 3/12, 4/12, etc.

Specialty Designer The individual or

organization having responsibility for the design

of the specialty items. This responsibility shall be

in accordance with the state’s statues and

regulations governing the professional

registration and certification of architects or

engineers. Also referred to as component

designer, specialty engineer, design engineer,

registered engineer, and engineer, but hereinafter

will be referred to as Specialty Designer. The

requirement for a Specialty Designer is typically

called out on architectural specifications or

structural general notes. The Specialty Designer

is typically not the Structural Engineer-of-

Record.

Specifications Written instructions, which, with

the plans, define the materials, standards, design

of the products, and workmanship expected on a

construction project.

Specified Minimum Yield Stress Lower limit of

yield stress specified for a material as defined by

ASTM

Splice The point at which two chord members of

the same slope are joined together to form a

single member.

Static Load A load or series of loads that are

supported by, or are applied to, a structure so

gradually that forces caused by change in

momentum of the load and structural elements

can be neglected and all parts of the system at

any instant are essentially in equilibrium.

Strain The geometrical expression of

deformation caused by the action of stress on a

physical body.

Stress A unit force working within a member,

usually expressed in pounds per square inch

(psi).

Strongback A load distribution member typically

used in a floor truss system and installed

perpendicular through the trusses.

Structural Analysis Determination of load

effects on members and connections based on

principles of structural mechanics.

Structural Component Member, connector,

connecting element or assemblage.

Structural Engineer-of-Record The design

professional who is responsible for sealing the

contract documents, which indicates that he or

she has performed or supervised the analysis,

design and document preparation for the

structure and has knowledge of the

requirements for the load carrying structural

system.

Structural Sheathing The covering (e.g.,

plywood, oriented strand board or steel deck)

used directly over structural members (e.g.,

joists) to distribute loads, brace walls, and

generally strengthen the assembly.

Sub-Contractor The individual or organization

with whom a contractor has contracted to

furnishl and/or install a portion of the project.

Tensile Strength (of material) See Ultimate

Strength.

Top Chord An inclined or horizontal member

that establishes the upper edge of a truss.

Truss A coplanar system of structural members

joined together at their ends usually to construct

a series of triangles that form a stable beam-like

framework.

Truss Designer Also referred to as truss

engineer, design engineer and registered

engineer, is an individual or organization

responsible for the design of cold-formed steel

trusses.

Truss Manufacturer An individual or

organization engaged in the manufacturing of

site-built or in-plant trusses. Also called the

Truss Fabricator.

Unbalanced Load Live loads that are applied

non-uniformly across the span of the truss. This

type of loading is required by most building

codes.

Ultimate Strength (Fu) The property of steel

associated with the maximum stress that can be

developed prior to rupture. Also known as tensile

strength.

Uniform Load A total load that is equally

distributed over a given length, usually

expressed in pounds per square foot (psf).

Valley A depression in a roof where two roof

slopes meet.

Valley Set A group of trusses required to fill in a

section of a roof. Valley trusses generally have

only vertical webs and are supported on top of

other trusses.

REFERENCES/RESOURCES

1 2 3 4 5 6 7 8

8.06

REFERENCES/RESOURCES

Variable Load. Load not classified as permanent

load.

Web Crippling. The localized permanent

(inelastic) deformation of the web member

subjected to concentrated load or reaction at

bearing supports.

Webs. Members that join the top and bottom

chords to form the triangular patterns that give

truss action, usually carrying tension or

compression stresses (no bending).

Web Stiffener. Additional material that is

attached to the web to strengthen the member

against web crippling. Also called bearing or

transverse stiffener.

Yield Strength (Fy). Stress at which a material

exhibits a specified limiting deviation from the

proportionality of stress to strain as defined by

ASTM.

Z-Shape. A point-symmetric or non-symmetric

section which is used as a chord member in a

truss.

* Terms shown with an asterisk are usually

qualified by the type of load effect, for example,

nominal tensile strength, available compressive

strength, or design flexural strength.

Glossary

Sources

• AISC and AISI Standard Definitions for Use

in the Design of Steel Structures, 2007

Edition

• AIS S100-07: North American

Specification for the Design of Cold-Formed

Steel Structural Members; American Iron and

Steel Institute; 2007 Edition with

Supplement 2

• AISI-S200-07:

AISI North American

Standard for Cold-Formed Steel Framing -

General Provisions; 2007 Edition.

• AISI-S214-07:

AISI Norh American

Standard for Cold-Formed Steel Framing -

Truss Design, 2007 Edition.

• The Encyclopedia of Trusses, Alpine

Engineered Products, Inc.

Definitions presented in this Glossary were

compiled and provided solely for the

education of the reader. While every effort

has been made to keep these definitions

accurate, helpful and up-to-date, it is not the

intent of this compilation to supplant existing

or future regulatory or statutory definitions.

1 2 3 4 5 6 7 8

8.07

Weights of Materials

Composition Roofing

2-15 lb. and 1-90 lb. 1.75

3-15 lb. and 1-90 lb. 2.2

Felt, 3 ply 1.5

Felt, 3 ply and gravel 5.6

Felt, 4 ply and gravel 6.0

Felt, 5 ply and gravel 6.5

3/4” ceramic or quality tile 10.0

Single-ply (mod. bitumen) 1.0

Misc. Roofing Materials

Roll roofing 1.0

Asphalt shinges 2.0

Book tile (2”) 12.0

Cement tile 16.0

Clay tile (w/ mortar) 10.0

Spanish 19.0

Roman 12.0

Misc. Decking Materials

Tectum (1”) 2.0

Vermiculite concrete 2.6

Insulrock (1”) 2.7

Wood Decking

3/8" plywood 1.1

1/2” plywood 1.5

5/8” plywood 1.8

3/4” plywood 2.3

1-1/8” plywood 3.4

1” sheathing 2.3

2” decking 4.3

3” decking 7.0

4” decking 9.3

Roof Sheathing

3/8” plywood 1.1

1/2” plywood 1.5

5/8” plywood 1.8

3/4” plywood 2.2

1-1/8” plywood 3.3

1” (sheathing) nominal 2.1

Floor

Hardwood (nominal 1”) 3.8

Concrete (per 1” of thickness)

Insulating lightweight 2.5

Lightweight 6.0-10.0

Reinforced 12.5

Linoleum or soft tile 1.5

3/4” ceramic or quality tile 10.0

Terrazo (1.5”) 19.0

Cement finish (per 1” thick) 12.0

Corrugated Galvanized Steel Deck (2)

57 mil (16 GA) 3.5

45 mil (18 GA) 2.8

34 mil (20 GA) 2.1

28 mil (22 GA) 1.7

24 mil (24 GA) 1.1

18 mil (26 GA) 1.0

Roll or Batt Insulation

Rock wool (1”) 0.2

Glass wool (1”) 0.1

Rigid Insulation

Temlock (1”) 1.2

Cork 0.7

Gold bond (1”) 1.5

Styrofoam (1”) 0.2

Foamglass (1”) 0.8

Rigid fiber glass (1”) 1.5

Ceilings

Acoustical fiber tile 1.0

1/2” gypsum board 2.0

5/8” gypsum board 2.5

Plaster (1” thick) 8.0

Metal suspension system 0.5

Metal suspension with tile 1.8

Wood suspension system 2.0

Wood suspension with tile 2.5

All weights shown in PSF unless noted otherwise.

Weights and dimensions shown are generic - physical properties of actual materials may vary from product to product.

REFERENCES/RESOURCES

1 2 3 4 5 6 7 8

8.08

REFERENCES/RESOURCES

Industry-Best Resources

TrusSteel has created the industry’s most

complete set of technical resources for the

design and application of pre-engineered Cold-

Formed Steel trusses. This information is

published in several formats that are available to

professionals who specify and design with CFS

trusses.

www.TrusSteel.com

The TrusSteel Web site is the industry’s most

comprehensive resource on CFS trusses. Learn

the history of Alpine and TrusSteel, find a local

Authorized Fabricator, download Standard

Details, research UL and code issues, request an

AIA/CES seminar and much more. Get TrusSteel

information when you need it - 24 / 7 / 365.

Truss Manual CD

TrusSteel also publishes the Manual you are

reading as an interactive CD that is available to

architects and engineers who specify and design

with CFS trusses. The CD contains not only this

manual but also the complete library of TruSteel

Standard Details in DXF and DWG CAD file

formats. To request a copy of the Design Manual

CD, just visit www.TrusSteel.com.

TrusSteel Standard Details

TrusSteel maintains this growing library of over

100 details and makes it available, free of

charge, to industry professionals. Use these

details for reference during design, then cut-

and-paste them right into your construction

documents.

Guide Specification

The TrusSteel Guide Spec is written in the

standard three-part CSI format. This spec is

available from our Web site, and from the Design

Manual CD, in pure text format that you can cut-

and-paste without fear of reformatting your

current specs or importing contaminated files.

TrusSteel Authorized Fabricators

Your local Authorized Fabricators can be one of

your most valuable resources when you are

planning and designing your building. These roof

framing specialists can help you realize your

design vision in the most economical, easily-built

and safe manner. Need information on truss

designs, prices and delivery? Need help in

working out a difficult roof plan? Your local

Authorized Fabricator can help. Go to

www.TrusSteel.com to find a Fabricator near

you.

For more information, contact: info@TrusSteel.com or go to: www.TrusSteel.com

or call 888-565-9181.

The World Leader in

Cold-Formed Steel Trusses

Truss Design Manual

a division of ITW Building Components Group

888.565.9181 • www.TrusSteel.com

a division of ITW Building Components Group

Truss Design Manual

GUIDE 2005 Z 9181 Trussteel Design Manual 2012

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