84新规范双孔箱涵结构设计

钢筋混凝土双孔箱涵结构设计数据输入：说明1.孔径及净空净跨径L0=4m净高h0=2.5m孔数m=22.设计安全等级设计安全等级11为一级，2为二级，3为三级3.汽车荷载荷载等级公路－1级1为I级，2为II级，3为II级折减4.填土情况箱涵顶填土厚H=0.55m≥0.5m土的内摩擦角Φ=30°填土容重γ1=18kN/m3地基承载力[σ0]=150kPa5.建筑材料普通钢筋种类21为R235，2为HRB335，3为HRB400，4为KL400主钢筋直径20mm涵身混凝土强度等级C2515~506.箱涵尺寸顶板、底板厚度δ=0.35m倒角C1=0.25m侧墙厚度t=0.35m倒角C2=0.25m基础襟边c=0.1m基础高度d=0.1m附注：有填充颜色的单元格需要按说明输入数值。1、孔径及净空净跨径L0=4m净高h0=2.5m孔数m=22、设计安全等级一级结构重要性系数r0=1.13、汽车荷载荷载等级公路—Ⅰ级4、填土情况涵顶填土高度H=0.55m土的内摩擦角Φ=30°填土容重γ1=18kN/m3地基容许承载力[σ0]=150kPa5、建筑材料普通钢筋种类HRB335主钢筋直径20mm钢筋抗拉强度设计值fsd=280MPa涵身混凝土强度等级C25涵身混凝土抗压强度设计值fcd=11.5MPa涵身混凝土抗拉强度设计值ftd=1.23MPa钢筋混凝土重力密度γ2=25kN/m3基础混凝土强度等级C15混凝土重力密度γ3=24kN/m3(一)截面尺寸拟定(见图L-01)顶板、底板厚度δ=0.35mC1=0.25m侧墙厚度t=0.35mC2=0.25m横梁计算跨径LP=L0+t=4.35mL=2L0+3t=9.05m侧墙计算高度hP=h0+δ=2.85mh=h0+2δ=3.2m基础襟边c=0.1m基础高度d=0.1m基础宽度B=9.25m(二)荷载计算1、恒载恒载竖向压力p恒=γ1H+γ2δ=18.65kN/m2恒载水平压力顶板处eP1=γ1Htan2(45°-φ/2)=3.30kN/m2图L-01底板处eP2=γ1(H+h)tan2(45°-φ/3)=22.50kN/m22、活载汽车后轮着地宽度0.6m，由《公路桥涵设计通用规范》(JTGD60—2004)第4.3.4条规定，按30°角向下分布。一个汽车后轮横向分布宽1.3/2m1.8/2m故横向分布宽度a=(0.6/2+Htan30°)×2+1.3=2.535m同理，纵向，汽车后轮着地长度0.2m0.2/2+Htan30°=0.418m1.4/2m故b=(0.2/2+Htan30°)×2=0.835m∑G=140kN车辆荷载垂直压力q车=∑G/(a×b)=66.13kN/m2车辆荷载水平压力e车=q车tan2(45°-φ/2)=22.04kN/m2(三)内力计算1、构件刚度比K=(I1/I2)×(hP/LP)=0.66钢筋混凝土双孔箱涵结构设计0.62m0.6/2+Htan30°=一、设计资料二、设计计算第3页，共17页u=2K+1=2.312、节点弯矩和轴向力计算(1)a种荷载作用下(图L-02)涵洞四角节点弯矩MaA=MaC=MaE=MaF=-1/u·pLP2/12MBA=MBE=MDC=MDF=-(3K+1)/u·pLP2/12MBD=MDB=0横梁内法向力Na1=Na2=Na1'=Na2'=0侧墙内法向力Na3=Na4=(MBA-MaA+pLp2/2)/Lp图L-02Na5=-(Na3+Na4)恒载p=p恒=18.65kN/m2MaA=MaC=MaE=MaF=-12.73kN·mMBA=MBE=MDC=MDF=-37.75kN·mNa3=Na4=34.81kNNa5=-69.62kN车辆荷载p=q车=66.13kN/m2MaA=MaC=MaE=MaF=-45.14kN·mMBA=MBE=MDC=MDF=-133.85kN·mNa3=Na4=123.44kNNa5=-246.88kN(2)b种荷载作用下(图L-03)MbA=MbC=MbE=MbF=-K·phP2/6uMBA=MBE=MDC=MDF=K·phP2/12uMBD=MDB=0Nb1=Nb2=Nb1'=Nb2'=phP/2Nb3=Nb4=(MBA-MbA)/LpNb5=-(Nb3+Nb4)恒载p=eP1=3.30kN/m2MbA=MbC=MbE=MbF=-1.27kN·mMBA=MBE=MDC=MDF=0.63kN·m图L-03Nb1=Nb2=Nb1'=Nb2'=4.70kNNb3=Nb4=-0.44kNNb5=0.87kN(3)c种荷载作用下(图L-04)Φ=20u(K+6)/K=469.36McA=McE=-(8K+59)·phP2/6ΦMcC=McF=-(12K+61)·phP2/6ΦMBA=MBE=(7K+31)·phP2/6ΦMDC=MDF=(3K+29)·phP2/6ΦMBD=MDB=0Nc1=Nc1'=phP/6+(McC-McA)/hPNc2=Nc2'=phP/3-(McC-McA)/hPNc3=Nc4=(MBA-McA)/LpNc5=-(Nc3+Nc4)恒载p=eP2-eP1=19.20kN/m2McA=McE=-3.56kN·mMcC=McF=-3.81kN·mMBA=MBE=1.97kN·m图L-04MDC=MDF=1.71kN·mNc1=Nc1'=9.03kNNc2=Nc2'=18.33kNNc3=Nc4=1.27kNNc5=-2.54kN(4)d种荷载作用下(图L-05)Φ1=20(K+2)(6K2+6K+1)=398.62Φ2=u/K=3.53Φ3=120K3+278K2+335K+63=435.56Φ4=120K3+529K2+382K+63=574.10Φ5=360K3+742K2+285K+27=633.47Φ6=120K3+611K2+558K+87=748.61MdA=(-2/Φ2+Φ3/Φ1)·phP2/4MdE=(-2/Φ2-Φ3/Φ1)·phP2/4MdC=-(2/Φ2+Φ5/Φ1)·phP2/24第4页，共17页MdF=-(2/Φ2-Φ5/Φ1)·phP2/24MBA=-(-2/Φ2+Φ4/Φ1)·phP2/24MBE=-(-2/Φ2-Φ4/Φ1)·phP2/24MDC=(1/Φ2+Φ6/Φ1)·phP2/24MDF=(1/Φ2-Φ6/Φ1)·phP2/24MBD=-Φ4·phP2/12Φ1MDB=Φ6·phP2/12Φ1Nd1=(MdC+phP2/2-MdA)/hP图L-05Nd2=php-Nd1Nd1'=(MdF-MdE)/hPNd2'=php-Nd1'Nd3=(MBA+MBD-MdA)/LPNd4=(MBE+MBD-MdE)/LPNd5=-(Nd3+Nd4)车辆荷载p=e车=22.04kN/m2MdA=23.52kN·mMdE=-74.30kN·mMdC=-16.09kN·mMdF=7.62kN·mMBA=-14.98kN·mMBE=6.51kN·mMDC=16.13kN·mMDF=-11.89kN·mMBD=-21.49kN·mMDB=28.02kN·mNd1=-45.31kNNd2=108.13kNNd1'=0.39kNNd2'=62.43kNNd3=-13.79kNNd4=13.64kNNd5=0.15kN(5)节点弯矩、轴力计算及荷载效应组合汇总表按《公路桥涵设计通用规范》(JTGD60—2004)第4.1.6条进行承载能力极限状态效应组合MAMEMCMFMBAMBEMDCMDFMBDMDB-12.73-12.73-12.73-12.73-37.75-37.75-37.75-37.750.000.00-15.27-15.27-15.27-15.27-45.30-45.30-45.30-45.300.000.00-1.27-1.27-1.27-1.270.630.630.630.630.000.00-3.56-3.56-3.81-3.811.971.971.711.710.000.00-6.75-6.75-7.11-7.113.653.653.293.290.000.00-45.14-45.14-45.14-45.14-133.85-133.85-133.85-133.850.000.0023.52-74.30-16.097.62-14.986.5116.13-11.89-21.4928.02-30.26-167.21-85.71-52.52-208.36-178.27-164.82-204.05-30.0839.23-52.29-189.24-108.10-74.90-250.01-219.93-206.83-246.06-30.0839.23N1N2N1'N2'N3N4N50.000.000.000.0034.8134.81-69.620.000.000.000.0041.7741.77-83.554.704.704.704.70-0.44-0.440.879.0318.339.0318.331.271.27-2.5419.2332.2519.2332.251.171.17-2.340.000.000.000.00123.44123.44-246.88-45.31108.130.3962.43-13.7913.640.15-63.43151.390.5587.41153.51191.91-345.42-44.21183.6319.77119.7196.5234.9-431.303、构件内力计算(跨中截面内力)(1)顶板1(图L-06)x=LP/2荷载种类恒载a1.2×∑结构、土的重力bc1.4×∑土侧压力ad1.4×∑汽车荷载效应组合车辆荷载a1.2×∑结构、土的重力b恒载c1.4×∑土侧压力ad1.4×∑汽车荷载效应组合车辆荷载N(kN)荷载种类M(kN·m)第5页，共17页P=1.2p恒+1.4q车=114.96kNNx=N1=-44.21kNMx=MA+N3x-Px2/2=103.07kN·mVx=Px-N3=53.59kN顶板1'x=LP/2P=1.2p恒+1.4q车=114.96kNNx=N1'=19.77kNMx=ME+N4x-Px2/2=49.64kN·mVx=Px-N4=15.19kN(2)底板2(图L-07)ω1=1.2p恒+1.4(q车+3e车HP2/4LP2)=124.90kN/m2ω2=1.2p恒+1.4q车=114.96kN/m2x=LP/2Nx=N2=183.63kNMx=MC+N3x-ω2·x2/2-5x3(ω1-ω2)/12LP=37.47kN·mVx=ω2x+3x2(ω1-ω2)/2LP-N3=69.80kN底板2'ω1=1.2p恒+1.4q车=114.96kN/m2ω2=1.2p恒+1.4(q车-3e车HP2/4LP2)=105.03kN/m2x=LP/2Nx=N2'=119.65kNMx=MF+N4x-ω2·x2/2-x3(ω1-ω2)/6LP=183.56kN·mVx=ω2x+x2(ω1-ω2)/2LP-N4=4.39kN(3)左侧墙(图L-08)ω1=1.4eP1+1.4e车=35.48kN/m2ω2=1.4eP2+1.4e车62.36kN/m2x=hP/2Nx=N3=196.45kNMx=MA+N1x-ω1·x2/2-x3(ω2-ω1)/6hP=-155.86kN·mVx=ω1x+x2(ω2-ω1)/2hP-N1=104.35kN(4)右侧墙(图L-09)ω1=1.4eP1=4.62kN/m2ω2=1.4eP2=31.50kN/m2x=hP/2Nx=N4=234.85kNMx=ME+N1'x-ω1·x2/2-x3(ω2-ω1)/6hP=-170.30kN·mVx=ω1x+x2(ω2-ω1)/2hP-N1'=-3.61kN(5)中间墙(图L-10)x=hP/2Nx=N5=-431.30kNMx=MBD+(N1+N1')x=-64.91kN·mVx=-(N1+N1')=24.44kN(5)构件内力汇总