CSA A23.3 04 PT SL Example 001
User Manual: CSA A23.3-04 PT-SL Example 001
Open the PDF directly: View PDF 
.
Page Count: 6
| Download | |
| Open PDF In Browser | View PDF |
Software Verification PROGRAM NAME: REVISION NO.: ETABS 0 CSA 23.3-04 PT-SL EXAMPLE 001 Post-Tensioned Slab Design PROBLEM DESCRIPTION The purpose of this example is to verify the slab stresses and the required area of mild steel strength reinforcing for a post-tensioned slab. A one-way simply supported slab is modeled in ETABS. The modeled slab is 254 mm thick by 914 mm wide and spans 9754 mm as shown in shown in Figure 1. Prestressing tendon, Ap Mild Steel, As 229 mm 254 mm 25 mm Length, L = 9754 mm 914 mm Section Elevation Figure 1 One-Way Slab A 254-mm-wide design strip is centered along the length of the slab and has been defined as an A-Strip. B-strips have been placed at each end of the span CSA 23.3-04 PT-SL EXAMPLE 001 - 1 Software Verification PROGRAM NAME: REVISION NO.: ETABS 0 perpendicular to Strip-A (the B-Strips are necessary to define the tendon profile). A tendon with two strands, each having an area of 99 mm2, has been added to the A-Strip. The self weight and live loads were added to the slab. The loads and posttensioning forces are as follows: Loads: Dead = self weight, Live = 4.788 KN/m2 The total factored strip moments, required area of mild steel reinforcement, and slab stresses are reported at the midspan of the slab. Independent hand calculations have been compared with the ETABS results and summarized for verification and validation of the ETABS results. GEOMETRY, PROPERTIES AND LOADING Thickness Effective depth Clear span T, h = d = L = 254 229 9754 mm mm mm Concrete strength Yield strength of steel Prestressing, ultimate Prestressing, effective Area of Prestress (single strand) Concrete unit weight Modulus of elasticity Modulus of elasticity Poisson’s ratio f 'c fy fpu fe Ap wc Ec Es = = = = = = = = = 30 400 1862 1210 198 23.56 25000 200,000 0 MPa MPa MPa MPa mm2 KN/m3 N/mm3 N/mm3 Dead load Live load wd wl = = self 4.788 KN/m2 KN/m2 TECHNICAL FEATURES OF ETABS TESTED Calculation of the required flexural reinforcement Check of slab stresses due to the application of dead, live, and post-tensioning loads. CSA 23.3-04 PT-SL EXAMPLE 001 - 2 Software Verification PROGRAM NAME: REVISION NO.: ETABS 0 RESULTS COMPARISON Table 1 shows the comparison of the ETABS total factored moments, required mild steel reinforcing, and slab stresses with the independent hand calculations. Table 1 Comparison of Results FEATURE TESTED Factored moment, Mu (Ultimate) (kN-m) Area of Mild Steel req’d, As (sq-cm) Transfer Conc. Stress, top (D+PTI), MPa Transfer Conc. Stress, bot (D+PTI), MPa Normal Conc. Stress, top (D+L+PTF), MPa Normal Conc. Stress, bot (D+L+PTF), MPa Long-Term Conc. Stress, top (D+0.5L+PTF(L)), MPa Long-Term Conc. Stress, bot (D+0.5L+PTF(L)), MPa INDEPENDENT RESULTS ETABS RESULTS DIFFERENCE 159.4 159.4 0.00% 16.25 16.33 0.49% 5.058 5.057 -0.02% 2.839 2.839 0.00% 10.460 10.467 0.07% 8.402 8.409 0.08% 7.817 7.818 0.01% 5.759 5.760 0.02% COMPUTER FILE: CSA A23.3-04 PT-SL EX001.EDB CONCLUSION The ETABS results show an exact comparison with the independent results. CSA 23.3-04 PT-SL EXAMPLE 001 - 3 Software Verification PROGRAM NAME: REVISION NO.: ETABS 0 HAND CALCULATIONS: Design Parameters: Mild Steel Reinforcing fcu = 30MPa fy = 400MPa Post-Tensioning fpu = 1862 MPa fpy = 1675 MPa Stressing Loss = 186 MPa Long-Term Loss = 94 MPa fi = 1490 MPa fe = 1210 MPa c 0.65 , S 0.85 1 = 0.85 – 0.0015f'c 0.67 = 0.805 1 = 0.97 – 0.0025f'c 0.67 = 0.895 Prestressing tendon, Ap Mild Steel, As 229 mm 254 mm 25 mm Length, L = 9754 mm Elevation 914 mm Section Loads: Dead, self-wt = 0.254 m x 23.56 kN/m3 = 5.984 kN/m2 (D) x 1.25 = 7.480 kN/m2 (Du) Live, = 4.788 kN/m2 (L) x 1.50 = 7.182 kN/m2 (Lu) Total = 10.772 kN/m2 (D+L) = 14.662 kN/m2 (D+L)ult =10.772 kN/m2 x 0.914m = 9.846 kN/m, u = 16.039 kN/m2 x 0.914m = 13.401 kN/m Ultimate Moment, M U CSA 23.3-04 PT-SL EXAMPLE 001 - 4 wl12 = 13.401 x (9.754)2/8 = 159.42 kN-m 8 Software Verification PROGRAM NAME: REVISION NO.: Ultimate Stress in strand, f pb f pe cy ETABS 0 8000 d p cy lo p Ap f pr s As f y 0.9 197 1347 0.85 1625 400 61.66 mm 0.805 0.65 30.0 0.895 914 1c f 'c 1b f pb 1210 8000 229 61.66 1347 MPa 9754 Depth of the compression block, a, is given as: Stress block depth, a d d 2 2M * 1 f 'c c b 0.229 0.2292 2 159.42 55.18 0.805 30000 0.65 0.914 Ultimate force in PT, Fult , PT AP ( f PS ) 197 1347 1000 265.9 kN Ultimate moment due to PT, a 55.18 M ult , PT Fult , PT d 265.9 0.229 0.85 45.52 kN-m 2 2 Net Moment to be resisted by As, M NET MU M PT 159.42 45.52 113.90 kN-m The area of tensile steel reinforcement is then given by: As M NET = 0.87 f y z 113.90 1e6 1625 mm 2 55.18 0.87 400 229 2 Check of Concrete Stresses at Midspan: Initial Condition (Transfer), load combination (D+PTi) = 1.0D+0.0L+1.0PTI Tendon stress at transfer = jacking stress stressing losses = 1490 186 = 1304 MPa The force in the tendon at transfer, = 1304 197.4 1000 257.4 kN CSA 23.3-04 PT-SL EXAMPLE 001 - 5 Software Verification PROGRAM NAME: REVISION NO.: ETABS 0 Moment due to dead load, M D 5.984 0.914 9.754 8 65.04 kN-m 2 Moment due to PT, M PT FPTI (sag) 257.4 102 mm 1000 26.25 kN-m F M M PT 257.4 65.04 26.23 Stress in concrete, f PTI D 0.254(0.914) 0.00983 A S where S = 0.00983m3 f 1.109 3.948 MPa f 5.058(Comp) max, 2.839(Tension) max Normal Condition, load combinations: (D+L+PTF) = 1.0D+1.0L+1.0PTF Tendon stress at normal = jacking stressing long-term = 1490 186 94 = 1210 MPa The force in tendon at normal, = 1210 197.4 1000 238.9 kN Moment due to dead load, M D 5.984 0.914 9.754 8 65.04 kN-m 2 Moment due to live load, M L 4.788 0.914 9.754 8 52.04 kN-m 2 Moment due to PT, M PT FPTI (sag) 238.9 102 mm 1000 24.37 kN-m Stress in concrete for (D+L+PTF), F M M PT 238.8 117.08 24.37 f PTI D L A S 0.254 0.914 0.00983 f 1.029 9.431 f 10.460(Comp) max, 8.402(Tension) max Long-Term Condition, load combinations: (D+0.5L+PTF(L)) = 1.0D+0.5L+1.0PTF Tendon stress at normal = jacking stressing long-term = 1490 186 94 = 1210 MPa The force in tendon at normal, = 1210 197.4 1000 238.9 kN Moment due to dead load, M D 5.984 0.914 9.754 8 65.04 kN-m 2 Moment due to live load, M L 4.788 0.914 9.754 8 52.04 kN-m 2 Moment due to PT, M PT FPTI (sag) 238.9 102 mm 1000 24.37 kN-m Stress in concrete for (D+0.5L+PTF(L)), M M PT F 238.9 91.06 24.33 f PTI D 0.5 L 0.254 0.914 0.00983 A S f 1.029 6.788 f 7.817(Comp) max, 5.759(Tension) max CSA 23.3-04 PT-SL EXAMPLE 001 - 6
Source Exif Data:
File Type : PDF File Type Extension : pdf MIME Type : application/pdf PDF Version : 1.5 Linearized : Yes Author : Create Date : 2016:08:04 16:08:04-07:00 Modify Date : 2016:08:04 16:08:04-07:00 XMP Toolkit : Adobe XMP Core 4.2.1-c043 52.372728, 2009/01/18-15:08:04 Producer : Acrobat Distiller 9.5.5 (Windows) Creator Tool : PScript5.dll Version 5.2.2 Format : application/pdf Creator : Title : Document ID : uuid:5f53424b-2b4a-4e54-8843-90dc8a92acfe Instance ID : uuid:339ae512-378d-4df8-8036-f6a5c04eff50 Page Count : 6EXIF Metadata provided by EXIF.tools