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25扭矩T=7.3kN.mAstl=804mm2保护层厚度c=25mmft=1.27N/mm2fyv=300N/mm2b=250mmbcor=200mmAcor=70000mm2Wt=b2/6*(3h-b)9895833mm3ρtl=Astl/b/h=0.8042.验算截面尺寸hw=h0=365mmV/bh0+T/0.8Wt=1.097448N/mm23.验算是否可不考虑剪力0.35ftbh0=40.56063kN4.验算是否可不考虑扭矩0.175ftWt=2.199349kN.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=1.3406667.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)=0.1152）计算抗剪箍筋用量Asv1/s=(V-0.7(1.5-βt)ftbh0)/(1.25fyvh0)=-0.0903）抗剪和抗扭箍筋用量Asv1'/s=Asv1/s+Ast1/s=0.296选用箍筋直径φ=8mm箍筋间距s=169.6248mm4）验算配箍率ρsv,min=0.28*ft/fyv=0.1185338.计算抗扭纵筋用量1）求AstlAstl=ζ*fyv*Ast1*ucor/fy/s=343.1抗扭纵筋根数选=2φ16As=402.1239343.12）验算配筋率受扭纵向钢筋的配筋率ρtl=Astl/bh=0.402124T/Vb=1.825T=1.825ρtl,min=0.6*(T/Vb)^0.5*ft/fy=0.343135ρtl单位弯矩M=18.8kN.mV=16kNAst1=50.3mm2as=35mmfc=11.9N/mm2fy=300N/mm2h=400mmhcor=350mmUcor=1100mmhw/b=1.4640.25βcfc=2.975N/mm2截面符合要求V=16kN可忽略剪力扭矩T=7.3kN.m不能忽略扭矩0.7ft=0.889N/mm2应按计算配置抗剪、抗扭钢筋1取βt=1s=436.5937单支箍筋面积Asv1'=50.3取s=160配箍率ρsv=Asv/bs=0.251327满足要求2满足要求满足要求