UNITED STATES DEPARTMENT OF AGRICULTURE 71168 UTP Bulletins 1751F 650
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UNITED STATES DEPARTMENT OF AGRICULTURE
Rural Utilities Service
BULLETIN 1751F-650
SUBJECT:
TO:
Aerial Plant Guying and Anchoring
All Telecommunications Borrowers
RUS Telecommunications Staff
EFFECTIVE DATE:
EXPIRATION DATE:
Date of Approval
Seven years from effective date
OFFICE OF PRIMARY INTEREST: Outside Plant Branch,
Telecommunications Standards Division
PREVIOUS INSTRUCTIONS: This bulletin replaces RUS
Telecommunications Engineering & Construction Manual (TE&CM)
Section 650, Guys and Anchors on Wire and Cable Lines, Issue 4,
dated February 1960; Addenda 1 and 2, dated October 1966, and
April 1967; respectively.
FILING INSTRUCTIONS: Discard RUS TE&CM Section 650, Guys and
Anchors on Wire and Cable Lines, Issue 4, dated February 1960;
Addenda 1 and 2, dated October 1966 and April 1967, respectively;
and replace them with this bulletin. File with 7 CFR 1751. This
bulletin is available to the RUS staff on RUSNET (text only) and
can be accessed via Internet at
http://www.usda.gov/rus/home/home.htm
PURPOSE: This bulletin provides RUS borrowers, consulting
engineers, contractors and other interested parties with
information on the guying and anchoring of aerial plant
facilities.
Wally Beyer
7/3/96
Administrator
Date
Bulletin 1751F-650
Page 2
TABLE OF CONTENTS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Abbreviations ............................................ 3
Definitions .............................................. 3
General .................................................. 7
Design Considerations .................................... 7
Filled Aerial Cable Guys ................................. 9
Guying of Unusual Cases ................................. 10
Guy Attachments to Poles and Push Braces Used in
Place of Guys ........................................... 10
Pole-to-Pole and Pole-to-Stub Pole Guys ................. 11
Electrical Protection of Exposed Guys and
Adding Guys to Existing Anchors ......................... 11
Guy Selection Examples .................................. 12
Anchor Selection ........................................ 14
Anchor Installation Precautions ......................... 16
TABLES & FIGURES
Table
1
Guy Strand Sizes - Utilities Grade 7 Wire, Galvanized Steel Strand ................... 8
Table
2
Guy Strand Sizes - Extra High Strength (EHS) 7 Wire, Galvanized Steel Strand ................... 8
Table
3
Minimum Guy Strand Selection Chart Filled Copper or Fiber Optic Cables ............... 9
Table
4
Guy Strand Selection Chart Filled, Self-Supporting Fiber Optic Cables ....... 10
Table
5
Minimum Anchor Selection Chart ................... 15
Figure 1
Guy Lead to Height Measurements .................. 17
Figure 2
Sidewalk Guy Determination ....................... 18
Figure 3
PF5-3 Anchor Assembly Unit - Alternative
Installation Method .............................. 19
INDEX:
Outside Plant
Construction
Telecommunications
Bulletin 1751F-650
Page 3
ABBREVIATIONS
°C
EHS
°F
ft
H
in.
L
lbf
L/H
m
MGN
mm
N
NESC
PF
RUS
TE&CM
Degrees Celsius
Extra High Strength Galvanized Steel
Degrees Fahrenheit
Feet
Height
Inches
Lead
Pounds-force
Lead/Height Ratio
Meter
Multigrounded Neutral
Millimeter
Newton
National Electrical Safety Code
Anchor Assembly Unit
Rural Utilities Service
Telecommunications Engineering and Construction Manual
DEFINITIONS
6M Guy: A guy strand size having a rated breaking strength of
6,000 pounds-force (lbf) [26,688 Newtons (N)].
10M Guy: A guy strand size having a rated breaking strength of
10,000 lbf (44,480 N).
16M Guy: A guy strand size having a rated breaking strength of
16,000 lbf (71,168 N).
Anchor: A device that serves as a reliable support to hold an
object firmly in place. The term anchor is normally associated
with cone, plate, screw, or concrete anchors, but the terms snub,
deadman and anchor log are usually associated with pole stubs or
logs set or buried in the ground to serve as temporary anchors.
The latter are often used at pull and tension sites.
Anchor rod: A steel or other metal rod designed for convenient
attachment to a buried anchor and also to provide for one or more
guy attachments above ground.
Deadend Guy: An installation of line or anchor guys to hold the
pole at the end of a line.
Bulletin 1751F-650
Page 4
Effectively Grounded: Intentionally connected to earth through a
ground connection or connections of sufficiently low impedance
and having sufficient current-carrying capacity to prevent the
buildup of voltages that may result in undue hazards to connected
equipment or to persons.
Guy: A tension member having one end secured to a fixed object
and the other end attached to a pole or other structural part
that it supports.
Guy Strand: A stranded group of wires used as a semiflexible
tension support between a pole or structure and the anchor rod,
or between structures.
Heavy Loading District: Horizontal wind pressure, at a right
angle to the line, of 4 pounds per square foot (190 Pascals) upon
the projected area of the cylindrical surfaces of all supported
wires (including suspension strand and cables) when coated with a
radial thickness of 0.50 inch (in.) [12.5 millimeters (mm)] of
ice at a temperature of 0°F (-20°C).
Height: The vertical distance between the attachment of the guy
strand to the pole and the surface of the ground at the anchor.
Lashed Aerial Cable: Cable that is attached to the separate
suspension strand by lashing wire to support the cable.
Lead: The horizontal distance between the pole and where the guy
attaches to the anchor.
Lead/Height Ratio:
“height distance”.
The ratio of the “lead distance” to the
Light Loading District: Horizontal wind pressure, at a right
angle to the line, of 9 pounds per square foot (430 Pascals) upon
the projected area of the cylindrical surfaces of all supported
wires (including suspension strand and cables) at a temperature
of 30°F (-1°C).
Medium Loading District: Horizontal wind pressure, at a right
angle to the line, of 4 pounds per square foot (190 Pascals) upon
the projected area of the cylindrical surfaces of all supported
wires (including suspension strand and cables) when coated with a
radial thickness of 0.25 in. (6.5 mm) of ice at a temperature of
15°F (-10°C).
PF1-3: An expanding anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 6,000 lbf (26,688 N).
Bulletin 1751F-650
Page 5
PF1-5: An expanding anchor
material and labor costs to
holding power of the anchor
PF1-7: An expanding anchor
material and labor costs to
holding power of the anchor
assembly unit which includes all the
install the anchor with rod. The
is 10,000 lbf (44,480 N).
assembly unit which includes all the
install the anchor with rod. The
is 16,000 lbf (71,168 N).
PF2-3: An plate anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 6,000 lbf (26,688 N).
PF2-5: An plate anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 10,000 lbf (44,480 N).
PF2-7: An plate anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 16,000 lbf (71,168 N).
PF3-3: A screw anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 6,000 lbf (26,688 N).
PF3-5: A screw anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 10,000 lbf (44,480 N).
PF3-7: A screw anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 16,000 lbf (71,168 N).
PF5-3: A rock anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
diameter of the rod is 3/4 in. (19 mm).
PF5-4: A rock anchor assembly unit which includes all the
material and labor costs to install the rod as the anchor.
diameter of the rod is 1 in. (25.4 mm).
The
PF6-3: A swamp anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 6,000 lbf (26,688 N).
PF6-4: A swamp anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 8,000 lbf (35,585 N).
PF6-5: A swamp anchor assembly unit which includes all the
material and labor costs to install the anchor with rod. The
holding power of the anchor is 10,000 lbf (44,480 N).
Pole: A column of wood supporting overhead cables usually by
means of brackets.
Bulletin 1751F-650
Page 6
Push Brace: A supporting member, usually of timber, placed
between a pole or other structural part of a line and the ground
or a fixed object.
Resident Engineer: The representative of the Engineer who is
delegated full-time “on-site” engineering responsibilities for
construction administration.
RUS Accepted (Material and Equipment): Material and equipment
which RUS has reviewed and determined that:
a. Final assembly is conducted within the United States,
Mexico, or Canada or any of their respective territories and the
cost of United States, Mexican, or Canadian, manufactured
components, in any combination, is more than 50 percent of the
total cost of all components utilized in the material or
equipment, and
b. The material or equipment complies with pertinent RUS or
industry standards and field experience has demonstrated that the
material or equipment is suitable for use on systems of RUS
telecommunications borrowers.
RUS Technically Accepted (Material and Equipment): Material and
equipment which RUS has reviewed and determined that:
a. Final assembly is not conducted within the United
States, Mexico, or Canada, or any of their territories, or the
cost of components within the material or equipment which are
manufactured within the United States, Mexico, or Canada, or any
of their territories, cost 50 percent or less than the total cost
of all components utilized in the material or equipment, and
b. The material or equipment complies with pertinent RUS or
industry standards and field experience has demonstrated that the
material or equipment is suitable for use on systems of RUS
telecommunications borrowers.
Self-Supporting Aerial Fiber Optic Cable: A cable consisting of
one or more buffered optical fibers factory assembled with a
messenger that supports the cable.
Span Length: The horizontal distance between two adjacent
supporting points of a cable.
Suspension Strand: A stranded group of wires supported above the
ground at intervals by poles or other structures and employed to
furnish within these intervals frequent points of support for
cables.
Bulletin 1751F-650
Page 7
1.
GENERAL
1.1 This bulletin discusses in particular the guying and
anchoring of aerial plant using filled copper and fiber optic
cables and filled, self-supporting fiber optic cables. The
information and recommendations in this bulletin are advisory.
1.2 Some of the work items associated with guying and anchoring
of aerial plant are as follows:
a.
Pre-installation inspection of anchors and anchor rods;
and
b.
Pre-installation inspection of guy strands.
1.3 Additional information for the use in guying and anchoring
of aerial plant facilities can be found in following documents:
2.
a.
Rural Utilities Service (RUS) Form 515, RUS Telephone
System Construction Contract (Labor and Materials);
b.
RUS Bulletin 345-153, Specifications and Drawings for
Construction of Pole Lines, Aerial Cables and Wires
(RUS Form 515f);
c.
RUS Bulletin 1751F-626, Staking of Aerial Plant;
d.
RUS Bulletin 1751F-630, Design of Aerial Plant;
e.
RUS Bulletin 1751F-635, Construction of Aerial Plant;
f.
RUS Bulletin 1751F-670, Outside Plant Corrosion
Considerations; and
g.
Latest edition of the National Electrical Safety
Code (NESC).
DESIGN CONSIDERATIONS
2.1 The size of the guy for lashed aerial plant facilities using
filled copper or filled fiber optic cables should be based on the
tension in the suspension strand when the filled copper or filled
fiber optic cable and strand are loaded to 60 percent of the
rated breaking strength of the suspension strand. The strength
of the guy used for lashed aerial plant construction is
independent of the span length and the three storm loading
districts as defined in the latest edition of the NESC.
2.2 The size of the guy for filled, self-supporting fiber optic
cables should be based on the tension in the stranded support
messenger when the filled, self-supporting fiber optic cable and
integral messenger are loaded to 60 percent of the rated breaking
Bulletin 1751F-650
Page 8
strength of the integral support messenger. The strength of the
guy used for filled, self-supporting fiber optic cable
construction is independent of the span length and the three
storm loading districts as defined in the latest edition of the
NESC.
2.3 Guy strands used in aerial plant construction should be RUS
accepted or technically accepted. Guy strands normally used in
aerial plant construction are given in Tables 1 and 2.
TABLE 1
Guy Strand Sizes
Utilities Grade
7 Wire, Galvanized Steel Strand
Diameter
Strand Designations
in. (mm)
6M
5/16 (7.9)
10M
3/8 (9.5)
16M
7/16 (11.1)
TABLE 2
Guy Strand Sizes
Extra High Strength (EHS)
7 Wire, Galvanized Steel Strand
Diameter
Strand Designations
in. (mm)
6M
1/4 (6.3)
10M
5/16 (7.9)
16M
7/16 (11.1)
2.4 The strength of guys used in aerial plant construction
should be in accordance with the required grade of construction
as defined in the latest edition of the NESC.
2.5 The guying of aerial plant facilities crossing railroads
should be performed in accordance with Section 24 of the latest
edition of the NESC and the “Specification For Communication
Lines Crossing the Tracks of Railroads” issued by the Association
of American Railroads.
2.6 Figure 1 shows the measurements for determining the “lead”
(L) and “height” (H) of guys. L/H ratios for best results of
aerial plant construction should be between 1/2 and 1. L/H
ratios less than 1/2 and greater than 1 should not be used unless
circumstances require otherwise. When L/H ratios less than 1/2
are required, the longest “lead” possible should be obtained and
the strength of poles, guys, and anchors should be increased as
required for the increased load.
Bulletin 1751F-650
Page 9
2.7 When sidewalk guy arms are required to be installed, the
sidewalk guy arms should be designed using larger strand sizes
and stronger poles than would be needed for normal guying
applications with the same L/H ratios. Figure 2 depicts a
sidewalk guy arm application and gives the procedure for
determining the size of the guy strand and class of pole that
should be installed.
3.
FILLED AERIAL CABLE GUYS
3.1 Guys for poles supporting lashed filled copper or fiber
optic cables at various corner angles and deadends for the three
commonly used suspension strands installed either singly or in
combinations on poles should be selected using the information
provided in Table 3. The information given in Table 3 can be
used for the selection of guy strands in the heavy, medium, and
light loading districts as defined in the latest edition of the
NESC.
TABLE 3
Minimum Guy Strand Selection Chart
Filled Copper or Fiber Optic Cables
Corners and Deadends
Heavy, Medium, and Light Loading Districts
Suspension
L/H
Strand Size
Ratio
5
10
15
20
25
30
35
40
45
50
55
60
6M
1/2
1
6M
6M
6M
6M
6M
6M
6M
6M
6M
6M
6M
6M
6M
6M
6M
6M
10M
6M
10M
6M
10M
6M
10M
6M
10M
1/2
1
6M
6M
6M
6M
6M
6M
6M
6M
10M
6M
10M
6M
10M
6M
16M
10M
16M
10M
16M
10M
16M
10M
16M
10M
16M
1/2
1
6M
6M
6M
6M
10M
6M
10M
6M
10M
10M
16M
10M
16M
10M
20M
6M
20M
16M
20M
16M
26M
16M
26M
16M
20M
1/2
1
6M
6M
6M
6M
10M
6M
16M
10M
16M
10M
16M
10M
20M
16M
26M
16M
26M
16M
26M
20M
32M
20M
32M
20M
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Corner Angles (Degrees)
For deadends use 60 degree corner angle guy size.
For 20M guy size, use 2 10M guys or equivalents.
For 26M guy size, use 1 10M guy and 1 16M guy or
equivalents.
For 32M guy size, use 2 16M guys or equivalents.
For 20M strand size, use 2 10M strands or
equivalents.
3.2 Guys for poles supporting filled, self-supporting fiber optic
cables at various corner angles and deadends using 1/4 in.
(6.35 mm) 7 wire, EHS, galvanized steel strand integral
supporting messengers should be selected using the information
provided in Table 4. The information given in Table 4 can be
used for the selection of guy strands in the heavy, medium, and
light loading districts as defined in the latest edition of the
NESC.
Bulletin 1751F-650
Page 10
TABLE 4
Guy Strand Selection Chart
Filled, Self-Supporting Fiber Optic Cables
Maximum Corner Angle in Degrees
Integral Messenger
L/H
for Size of Guy Strand
Size
Ratio
6M
10M
1/4 in. (6.35 mm)
1/2
35
60
1
60
-3.3 Guys placed at corners of 60 degrees or less should be
installed so that the guys bisect the corner angles unless strand
is double-deadended for other reasons.
3.4 Two head guys should be installed at corners that are
greater than 60 degrees but less than 90 degrees. The anchors
for each of the two guys should be installed approximately 2 feet
(ft) (610 mm) away from the “in-line” position toward the
bisectors of corner angles.
3.5 Two head guys should be installed at corners of 90 degrees
or greater. The anchors should be placed in line with cable
strands they hold. The thimbleye bolts, guy hooks, or other
suitable types of hardware should be installed through the poles
for each strand and its guy.
4.
GUYING OF UNUSUAL CASES
4.1 Guying may be required in certain unusual cases not covered
in this bulletin. In such cases the resident engineer or the
resident engineer’s representative should make a thorough study
of the situation and provide adequate guying in accordance with
the NESC or other local code, whichever is the more stringent
code.
4.2 In some situations, guying may be required at locations
where normal placement of anchor guys may be impracticable
because conditions do not allow sufficient L/H ratios to be
obtained while maintaining the required clearances. In these
circumstances sidewalk guys or other acceptable methods should be
used but only as last resorts.
5.
GUY ATTACHMENTS TO POLES AND PUSH BRACES USED IN
PLACE OF GUYS
5.1 Guys with downward pulls should be attached to poles by
means of thimbleye angle bolts, guy hooks, or other suitable
types of hardware. Guys with horizontal pulls should be attached
to poles by means of straight thimbleye bolts, guy hooks, or
other suitable types of hardware.
Bulletin 1751F-650
Page 11
5.2 Push braces should be used for supporting horizontal loads
on poles only when it is impracticable to place down guys or
overhead guys to stub poles. When push braces are used, the push
braces should be of the same pole classes as the poles they
brace. Push brace installations recommend the installation of
pole keys at pole butts to prevent lifting of poles during storm
conditions and plank footings where rock footings are not present
at butts of braces.
6.
POLE-TO-POLE AND POLE-TO-STUB POLE GUYS
6.1 Pole-to-pole guys should be only installed when it is
impracticable to install anchor guys.
6.2 The sizes of down guys at stub poles in pole-to-stub pole
guy installations should be selected as though the down guys are
to be attached to line corner poles instead of stub poles. The
overhead guy sizes should be the same sizes as required for down
guys with L/H ratios of 1.
7.
ELECTRICAL PROTECTION OF EXPOSED GUYS AND ADDING GUYS TO
EXISTING ANCHORS
7.1 Guys classified as exposed guys should be considered
electrical hazards to workmen and the public and should be
electrically protected.
7.2
Guys are considered to be exposed guys when:
a.
Guys pass over, under, or between supply conductors
having voltages that exceed 300 volts to ground;
b.
Guys are attached to poles carrying supply conductors
having voltages exceeding 300 volts to ground;
c.
The minimum horizontal distance between the guy
and the nearest supply conductor having voltages
that exceed 300 volts is less than 10 ft [3 meters (m)];
and
d.
Guys that are connected to continuous cable suspension
strands which are not systematically and effectively
grounded.
7.3 Electrical protection of exposed guys should be accomplished
by grounding the guys. The grounding of the guys should be
accomplished by:
a.
Bonding guys to vertical pole ground wires which
are connected to multiground neutrals (MGN); or
Bulletin 1751F-650
Page 12
b.
Bonding guys to effectively grounded cable
suspension strands.
7.4 Guys on the same throughbolts with effectively grounded
cable suspension strands are considered to be electrically bonded
to the suspension strands thus eliminating the need for separate
bonding conductors.
7.5 Auxiliary eye bolts should be use for attaching second guys
to existing anchor rods having eyes for only one guy strand.
When attachment of guys to existing anchors of foreign companies
is contemplated, the foreign companies should be notified.
Permission from the foreign companies should be obtained before
attaching the guys to the anchor rods. In any event the
attachment of second guys to existing anchors should only be
performed if it is known that the existing anchors have
sufficient holding power for the load of the two guys.
8.
GUY SELECTION EXAMPLES
8.1 For the selection of a guy associated with filled copper
cables, assume the following conditions:
a.
A pole supporting a filled copper cable lashed to
6M suspension strand;
b.
A corner angle of 45 degrees; and
c.
A L/H = 1/2.
The information given in items “a” through “c” above indicate
that Table 3 should be used for selecting the guy size. Table 3
shows that for a L/H = 1/2 at a 45 degree corner, a 10M guy
should be used to provide satisfactory holding power at the pole.
8.2 For selection of a guy associated with filled fiber optic
cables, assume the following conditions:
a.
A pole supporting a filled fiber optic cable lashed
to a 6M suspension strand;
b.
A corner angle of 30 degrees; and
c.
A L/H = 1.
The information given in items “a” through “c” above indicate
that Table 3 should be used for selecting the guy size. Table 3
shows that for a L/H = 1 at a 30 degree corner, a 6M guy should
be used to provide satisfactory holding power at the pole.
Bulletin 1751F-650
Page 13
8.3 For the selection of a guy associated with filled, selfsupporting fiber optic cables, assume the following conditions:
a.
Messenger of the self-supporting, filled fiber optic
cable is a 1/4 in. (6.35 mm) 7 wire, EHS, galvanized
steel strand;
b.
A corner angle of 45 degrees; and
c.
A L/H = 1/2.
The information given in items “a” through “c” above indicate
that Table 4 should be used for selecting the guy size. Table 4
shows that for a L/H = 1/2 at a 45 degree corner, a 10M guy
should be used to provide satisfactory holding power at the pole.
8.4 For selection of a sidewalk guy arm, assume the following
conditions:
a.
A 30 ft (9 m) pole carrying a filled copper cable
lashed to a 6M suspension strand;
b.
A minimum pole setting depth of 5.5 ft (1.7 m) for
the 30 ft (9 m) pole;
c.
A guy attachment distance of 1.0 ft (0.3 m) from the
top of the pole;
d.
A corner angle of 45 degrees; and
e.
A pipe having an outside diameter of 2 in. (50.8 mm)
and a length of 8 ft (2.4 m) which is attached to the
pole at a height of 8 ft (2.4 m) above the ground.
8.4.1 The information given in items “a” through “e” above
indicates that Figure 2 and Table 3 should be used in determining
the appropriate the sidewalk guy arm.
8.4.2 The solution for selecting the sidewalk guy arm should be
performed using the following steps:
a.
Compute AE from Figure 2 which indicates that
AE = (pole length minus pole setting depth minus
guy attachment distance from top of pole). Therefore,
AE = 30 ft - 5.5 ft - 1.0 ft = 23.5 ft using the English
Units listed in items “a” through “c” of Paragraph 8.4
of this bulletin. AE = 9 m - 1.7 m - 0.3 m = 7 m using
the Metric Units listed in Paragraph 8.4 of this
bulletin;
Bulletin 1751F-650
Page 14
9.
b.
Compute L/H from Figure 2 which indicates that
L/H = BC/AC = BC/(AE - CE). Therefore,
L/H = 8 ft/(23.5 ft - 8 ft) = 8 ft/15.5 ft = 1/1.9
using the English Units listed in item “e” of
Paragraph 8.4 and item “a” of Paragraph 8.4.2 of this
bulletin. Using the Metric Units listed in item “e” of
Paragraph 8.4 and item “a” of Paragraph 8.4.2
L/H = 2.4 m/(7 m - 2.4 m) = 2.4 m/4.6 m = 1/1.9. Since
the calculated L/H ratio of 1/1.9 is close to a L/H
ratio of 1/2, a L/H ratio of 1/2 is used for the
remaining calculations to determine the appropriate
sidewalk guy arm;
c.
Using Table 3, we see that for a 6M suspension strand
with a L/H = 1/2 and a corner angle of 45 degrees, the
guy strand selected for the application should be a 10M;
d.
Figure 2 indicates that for a 10M guy, the strand size
for the sidewalk guy should be 16M since AE, the height
of the guy attachment to the pole, which is 23.5 ft
(7 m), is between 20 ft (6.1 m) and 26 ft (7.9 m) as
indicated in Figure 2; and
e.
Finally Figure 2 indicates that a Class 3 pole should
be used in the sidewalk guy arm installation because the
L/H = 1/2.
ANCHOR SELECTION
9.1 Anchors should be selected based on the soil type at the
anchor location and the size of the guy selected from either
Table 3 or Table 4 of this bulletin.
9.2 The various soil types that may be encountered during anchor
installations are classified as follows:
a.
Class 1 - Hard rock (solid);
b.
Class 2 - All soil except hard rock, sand, and swamp;
c.
Class 3 - Sand; and
d.
Class 4 - Swamp.
9.3 After the guy size has been selected from either Table 3 or
Table 4 the anchor assembly unit for the appropriate guy size
should be selected from Table 5 based on the soil type where the
anchor is to be installed. Anchor assembly units given in Table
5 are defined in RUS Bulletin 345-153, Specifications and
Drawings for Construction of Pole Lines, Aerial Cables and
Wires(RUS Form 515f) and this bulletin. Where Table 5 provides
for more than one anchor assembly unit, a choice as to which
Bulletin 1751F-650
Page 15
anchor assembly unit to be
resident engineer based on
certain situations the use
to be installed to provide
aerial cable line.
Guy Size
6M
10M
16M
20M
(use 2 10M
Guys)
26M
(use 1 10M
Guy and
1 16M guy)
32M
( use 2 16M
Guys)
Note 6:
installed should be made by the
sound engineering judgment. In
of 2 anchors and guys may be required
satisfactory holding power of the
TABLE 5
Minimum Anchor Selection Chart
Anchor Assembly Unit
Soil Class
Class 1
Class 2
Class 3
PF5-3
PF1-3,
PF1-3,
or
PF2-3, or
PF2-3, or
PF-5-4
PF3-3
PF3-3
(Note 6)
PF5-3
PF1-5,
PF1-5,
or
PF2-5, or
PF2-5, or
PF5-4
PF3-5
PF3-5
(Note 6)
PF5-3
PF1-7,
PF1-7,
or
PF2-7, or
PF2-7, or
PF5-4
PF3-7
PF3-7
(Note 6)
2 PF5-3
2 PF1-5,
2 PF1-5,
or
2 PF2-5, or 2 PF2-5, or
2 PF5-4
2 PF3-5
2 PF3-5
(Note 6)
1 PF1-5 and 1 PF1-5 and
2 PF5-3
1 PF1-7;
1 PF1-7;
or
1 PF2-5 and 1 PF2-5 and
2 PF5-4
1 PF2-7; or 1 PF2-7; or
(Note 6)
1 PF3-5 and 1 PF3-5 and
1 PF3-7
1 PF3-7
2 PF5-3
2PF1-7,
2 PF1-7,
or
2 PF2-7, or 2 PF2-7, or
2 PF5-4
2 PF3-7
2 PF3-7
(Note 6)
Class 4
PF6-3
PF6-4
PF6-5
2 PF6-4
1 PF6-4 and
1 PF6-5
2 PF6-5
The PF5-3 and PF5-4 anchor assembly units are not
interchangeable.
9.4 PF5-3 anchor assembly units should be installed either in
accordance with the guide drawing listed in RUS Bulletin 345-153
(RUS Form 515f) or Figure 3 of this bulletin.
9.5 PF5-4 anchor assembly units should be installed in
accordance with the guide drawing listed in RUS Bulletin 345-153
(RUS Form 515f).
Bulletin 1751F-650
Page 16
9.6 Swamp anchors are screw type anchors. Swamp anchors use
galvanized steel sections of pipe as “rods”, which allow the
lengths of anchor rods to be as long as necessary by coupling the
pipe sections together. This allows anchors to be installed in
firm soil under swamps. The rods should be of sufficient length
that should result in penetration into the firm soil under the
swamps of at least 5 ft (1.5 m).
10.
ANCHOR INSTALLATION PRECAUTIONS
10.1 Holes dug for anchors should be no larger than necessary to
permit entry of anchors into the holes.
10.2 Care should be exercised in placing certain types of
expanding anchors to prevent earth or sand falling into the holes
and lodging between the plates which could prevent full expansion
of the plates and which could result in a reduction of the
anchor’s holding power.
10.3 Anchor holes should be dug to such depths that no more than
about 6 in. (152 mm) of anchor rods should be above ground after
strain is applied by guys. Anchor holes should be dug so that
anchor rods will be in line with guys. Anchor rods should not be
bent. Thimbleyes of anchor rods should never be covered with
earth.
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