預(yù)應(yīng)力束張拉計(jì)算

鋼絞線拉力計(jì)算15.2鋼絞線標(biāo)準(zhǔn)fpk=1860MPaEp=1.95×105MPaA=140mm2控制力σcon=0.75fpk單根鋼絞線張拉力NN=σcon×A=0.75×1860×1000×140÷1000000=195.3kNN總=19N=3710.7KN按規(guī)范要求，千斤頂拉力必須大于1.2倍N1.2N=1.2×3710.7=4452.8Kn故現(xiàn)場(chǎng)兩端張拉選用300噸千斤頂，單端張拉選用的450噸千斤頂拉力滿足施工需求。預(yù)應(yīng)力張拉伸長(zhǎng)量計(jì)算預(yù)應(yīng)力筋伸長(zhǎng)值的計(jì)算預(yù)應(yīng)力筋張拉時(shí)的控制應(yīng)力，應(yīng)以張拉時(shí)的實(shí)際伸長(zhǎng)值與理論計(jì)算伸長(zhǎng)值進(jìn)行校核。實(shí)際與理論伸長(zhǎng)值相差應(yīng)控制在±6%以內(nèi)。伸長(zhǎng)值的計(jì)算公式：式中:ΔLL—預(yù)應(yīng)力筋理論伸長(zhǎng)值，mm；PP—預(yù)應(yīng)力筋的平均張拉力(N)，直線筋取張拉端的拉力；兩端張拉的曲線筋，計(jì)算公式見下式。L—預(yù)應(yīng)力筋的長(zhǎng)度；AP—預(yù)應(yīng)力筋的截面面積（mm2）；EP—預(yù)應(yīng)力的彈性模量（N/mm2）；方法一：預(yù)應(yīng)力筋平均張拉力計(jì)算公式：式中：PP—預(yù)應(yīng)力筋平均張拉力（N）；P—預(yù)應(yīng)力筋張拉端的張拉力（N）；x—從張拉端至計(jì)算截面的孔道長(zhǎng)度(m)；?—從張拉端至計(jì)算截面曲線孔道部分切線的夾角之和（rad）;方法二：預(yù)應(yīng)力筋平均張拉力計(jì)算公式：式中：PP—預(yù)應(yīng)力筋平均張拉力（N）；P—預(yù)應(yīng)力筋前端的張拉力（N）；x—從張拉端至計(jì)算截面的孔道長(zhǎng)度(m)；?—從張拉端至計(jì)算截面曲線孔道部分切線的夾角之和（rad）;μ—預(yù)應(yīng)力筋與孔道壁的摩擦系數(shù)，參見下表；管道成型方式kμ值鋼絲束、鋼絞線預(yù)埋金屬波紋管0.00150.20-0.25以第一施工階段F1鋼絞線為例，鋼絞第二段線長(zhǎng)0.52m。預(yù)應(yīng)力筋平均張拉力計(jì)算公式：P=194.823kNk=0.0015μ=0.25x=0.52mθ=3Pp=194.823*（1-e-0.0015*0.52+0.25*3）/0.0015*0.52+0.25*3=193.481kN伸長(zhǎng)值的計(jì)算公式：Pp=193.481kNL=0.52mAp=140mm2Ep=195000MPa=193.481*0.52/1.4*10-4*1.95*108=3.7mm其余段落計(jì)算見下表F1鋼絞線伸長(zhǎng)量分段號(hào)曲線長(zhǎng)或直線長(zhǎng)(m)曲線轉(zhuǎn)角(度)轉(zhuǎn)角弧度孔道偏差系數(shù)k摩擦系數(shù)μ前端張拉力（N）末端張拉力(N)彈性模量(Mpa)kx+μθ前后端平均力(N)平均張拉力各段伸長(zhǎng)量(mm)81.6300.0000.00150.251953001948231950000.00244519506211.690.5230.0520.00150.251948231921401950000.013871934813.7101.3900.0000.00150.251921401917391950000.0020851919399.8110.5230.0520.00150.251917391890981950000.013871904193.6127.9700.0000.00150.251890981868511950000.01195518797554.9131.3980.1400.00150.251868511800651950000.0369921834589.3148.5800.0000.00150.251800651777631950000.0128717891456.2151.3980.1400.00150.251777631713071950000.0369921745358.9168.2400.0000.00150.251713071692031950000.0123617025551.4171.3980.1400.00150.251692031630581950000.0369921661318.5188.5800.0000.00150.251630581609731950000.0128716201650.9191.3980.1400.00150.251609731551271950000.0369921580508.0205.5200.0000.00150.251551271538481950000.0082815448831.2單端伸長(zhǎng)量（mm）：308.1兩端總伸長(zhǎng)量（mm）：616.2348AK0+656分離式立交橋鋼絞線理論伸長(zhǎng)量匯總序號(hào)編號(hào)單位理論總伸長(zhǎng)量備注1F1mm