梁抗扭计算

1.基本参数单位扭矩T=20000000kN.mV=1Astl=452mm2Ast1=50.3保护层厚度c=30mmas=35ft=1.1N/mm2fc=9.6fyv=210N/mm2fy=300b=250mmh=550bcor=190mmhcor=490Acor=93100mm2Ucor=1360Wt=b2/6*(3h-b)14583333mm3ρtl=Astl/b/h=0.3287270.25βcfc*0.8Wt=28000000验算是否需按计算配置抗扭钢筋0.7ftWt=11229167计算抗扭钢筋ζ=1Ast1/s=(T-0.35ftWt)/(1.2*ζ^0.5*fyv*Acor)=0.613158选Ast1=78.5s=128.0258取s=120配箍率ρsv=Asv/bs=0.523333ρsv,min=0.28*ft/fyv=0.1466670.523333计算抗扭纵筋Astl=ζ*fyv*Ast1*ucor/fy/s=622.8选=6φ12As=678.584622.8受扭纵向钢筋的配筋率ρtl=Astl/bh=0.493516T/Vb=80000T=2ρtl,min=0.6*(T/Vb)^0.5*ft/fy=0.311127ρtl单位kNmm2mmN/mm2N/mm2mmmmmm1.基本参数单位混凝土强度等级30扭矩T=4.47kN.mAstl=1206mm2保护层厚度c=25mmft=1.43N/mm2fyv=300N/mm2b=250mmbcor=200mmAcor=310000mm2Wt=b2/6*(3h-b)47395833mm3ρtl=Astl/b/h=0.30152.验算截面尺寸hw=h0=1565mmV/bh0+T/0.8Wt=0.158785N/mm23.验算是否可不考虑剪力0.35ftbh0=195.8206kN4.验算是否可不考虑扭矩0.175ftWt=11.86081kN.m5.验算是否按计算配置抗剪、抗扭钢筋V/bh0+T/Wt=N/mm26.计算剪扭构件混凝土承载力降低系数βtβt=1.5/(1+0.5VWt/Tbh0=1.2327377.计算箍筋用量1）计算抗扭箍筋用量取ζ=1Ast1/s=(T-0.35ftWt)/(1.2*ζ^0.5*fyv*Acor)=-0.1732）计算抗剪箍筋用量Asv1/s=(V-0.7(1.5-βt)ftbh0)/(1.25fyvh0)=-0.1533）抗剪和抗扭箍筋用量Asv1'/s=Asv1/s+Ast1/s=0.334选用箍筋直径φ=8mm箍筋间距s=150.6458mm4）验算配箍率ρsv,min=0.28*ft/fyv=0.1334678.计算抗扭纵筋用量1）求AstlAstl=ζ*fyv*Ast1*ucor/fy/s=1209.3抗扭纵筋根数选=8φ14As=1231.5041209.32）验算配筋率受扭纵向钢筋的配筋率ρtl=Astl/bh=0.307876T/Vb=1.118T=1.118ρtl,min=0.6*(T/Vb)^0.5*ft/fy=0.302336ρtl单位弯矩M=18.8kN.mV=16kNAst1=201.1mm2as=35mmfc=14.3N/mm2fy=300N/mm2h=1600mmhcor=1550mmUcor=3500mmhw/b=6.2640.25βcfc=3.575N/mm2截面符合要求V=16kN可忽略剪力扭矩T=4.47kN.m可忽略扭矩0.7ft=1.001N/mm2应按计算配置抗剪、抗扭钢筋1取βt=1s=-291.385单支箍筋面积Asv1'=50.3取s=150配箍率ρsv=Asv/bs=0.268083满足要求8满足要求满足要求