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=5.5m净高h0=2.9m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－2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=2.4m≥0.5m土的内摩擦角Φ=30°填土容重γ1=19kN/m3地基承载力[σ0]=200kPa5.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C3015~506.箱涵尺寸顶板、底板厚度δ=0.8m倒角C1=0.3m侧墙厚度t=1m倒角C2=0.3m基础襟边c=0m基础高度d=0m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=5.5m净高h0=2.9m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—Ⅱ级4、填土情况涵顶填土高度H=2.4m土的内摩擦角Φ=30°填土容重γ1=19kN/m3地基容许承载力[σ0]=200kPa5、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C30涵身混凝土抗压强度设计值fcd=13.8MPa涵身混凝土抗拉强度设计值ftd=1.39MPa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=0.8mC1=0.3m钢筋混凝土箱涵结构设计一、设计资料二、设计计算第3页，共25页侧墙厚度t=1mC2=0.3m横梁计算跨径LP=L0+t=6.5mL=2L0+3t=14m侧墙计算高度hP=h0+δ=3.7mh=h0+2δ=4.5m基础襟边c=0m基础高度d=0m基础宽度B=14m(二)荷载计算1、恒载恒载竖向压力p恒=γ1H+γ2δ=65.60kN/m2恒载水平压力顶板处eP1=γ1Htan2(45°-φ/2)=15.20kN/m2图L-01底板处eP2=γ1(H+h)tan2(45°-φ/3)=43.70kN/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=1.8+1.3=3.100m同理，纵向，汽车后轮着地长度0.2m0.2/2+Htan30°=1.486m1.4/2m故b=1.400m∑G=140kN车辆荷载垂直压力q车=∑G/(a×b)=32.26kN/m2车辆荷载水平压力e车=q车tan2(45°-φ/2)=10.75kN/m2(三)内力计算1、构件刚度比1.69m0.6/2+Htan30°=第4页，共25页K=(I1/I2)×(hP/LP)=0.29u=2K+1=1.582、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)/LpNa5=-(Na3+Na4)恒载p=p恒=65.60kN/m2MaA=MaC=MaE=MaF=-145.91kN·mMBA=MBE=MDC=MDF=-273.49kN·mNa3=Na4=193.57kNNa5=-387.15kN车辆荷载p=q车=32.26kN/m2MaA=MaC=MaE=MaF=-71.75kN·m图L-02MBA=MBE=MDC=MDF=-134.49kN·mNa3=Na4=95.19kNNa5=-190.37kN(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=15.20kN/m2MbA=MbC=MbE=MbF=-6.39kN·mMBA=MBE=MDC=MDF=3.19kN·m图L-03第5页，共25页Nb1=Nb2=Nb1'=Nb2'=28.12kNNb3=Nb4=-1.47kNNb5=2.95kN(3)c种荷载作用下(图L-04)Φ=20u(K+6)/K=683.40McA=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=28.50kN/m2McA=McE=-5.84kN·mMcC=McF=-6.14kN·mMBA=MBE=3.14kN·m图L-04MDC=MDF=2.84kN·mNc1=Nc1'=17.49kNNc2=Nc2'=35.23kNNc3=Nc4=1.38kNNc5=-2.76kN(4)d种荷载作用下(图L-05)Φ1=20(K+2)(6K2+6K+1)=149.33Φ2=u/K=5.43Φ3=120K3+278K2+335K+63=187.22Φ4=120K3+529K2+382K+63=222.24Φ5=360K3+742K2+285K+27=182.00Φ6=120K3+611K2+558K+87=304.50第6页，共25页MdA=(-2/Φ2+Φ3/Φ1)·phP2/4MdE=(-2/Φ2-Φ3/Φ1)·phP2/4MdC=-(2/Φ2+Φ5/Φ1)·phP2/24MdF=-(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=10.75kN/m2MdA=32.59kN·mMdE=-59.69kN·mMdC=-9.73kN·mMdF=5.22kN·mMBA=-11.39kN·mMBE=6.87kN·mMDC=13.64kN·mMDF=-11.38kN·mMBD=-18.26kN·mMDB=25.01kN·mNd1=-31.33kNNd2=71.12kN第7页，共25页Nd1'=-0.45kNNd2'=40.23kNNd3=-9.57kNNd4=7.43kNNd5=2.14kN(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-145.91-145.91-145.91-145.91-273.49-273.49-273.49-273.490.000.00-175.10-175.10-175.10-175.10-328.19-328.19-328.19-328.190.000.00-6.39-6.39-6.39-6.393.193.193.193.190.000.00-5.84-5.84-6.14-6.143.143.142.842.840.000.00-17.11-17.11-17.53-17.538.878.878.458.450.000.00-71.75-71.75-71.75-71.75-134.49-134.49-134.49-134.490.000.0032.59-59.69-9.735.22-11.396.8713.64-11.38######25.01-54.83-184.02-114.08-93.15-204.22-178.66-169.19-204.21######35.02-247.04-376.23-306.71-285.78-523.54-497.98-488.93-523.95######35.02N1N2N1'N2'N3N4N50.000.000.000.00193.57193.57-387.150.000.000.000.00232.29232.29-464.5728.1228.1228.1228.12-1.47-1.472.9517.4935.2317.4935.231.381.38-2.7663.8688.6963.8688.69-0.13-0.130.260.000.000.000.0095.1995.19-190.37-31.3371.12-0.4540.23-9.577.432.14-43.8699.56-0.6356.32119.86143.67-263.52荷载种类M(kN·m)1.4×∑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adad1.4×∑汽车车辆荷载N(kN)荷载种类恒载a1.2×∑结构、土的重力bc1.4×∑土侧压力第8页，共25页20.00188.2563.23145.0352.0375.8-727.843、构件内力计算(跨中截面内力)(1)顶板1(图L-06)x=LP/2P=1.2p恒+1.4q车=123.88kNNx=N1=20.00kNMx=MA+N3x-Px2/2=242.77kN·mVx=Px-N3=50.60kN顶板1'x=LP/2P=1.2p恒+1.4q车=123.88kNNx=N1'=63.23kNMx=ME+N4x-Px2/2=190.95kN·mVx=Px-N4=26.79kN(2)底板2(图L-07)ω1=1.2p恒+1.4(q车+3e车HP2/4LP2)=127.54kN/m2ω2=1.2p恒+1.4q车=123.88kN/m2x=LP/2Nx=N2=188.25kNMx=MC+N3x-ω2·x2/2-5x3(ω1-ω2)/12LP=175.05kN·mVx=ω2x+3x2(ω1-ω2)/2LP-N3=59.52kN底板2'ω1=1.2p恒+1.4q车=123.88kN/m2ω2=1.2p恒+1.4(q车-3e车HP2/4LP2)=120.22kN/m2x=LP/2图L-07图L-06荷载效应组合第9页，共25页Nx=N2'=145.02kNMx=MF+N4x-ω2·x2/2-x3(ω1-ω2)/6LP=297.50kN·mVx=ω2x+x2(ω1-ω2)/2LP-N4=20.85kN(3)左侧墙(图L-08)ω1=1.4eP1+1.4e车=36.33kN/m2ω2=1.4eP2+1.4e车76.23kN/m2x=hP/2Nx=N3=352.02kNMx=MA+N1x-ω1·x2/2-x3(ω2-ω1)/6hP=-283.60kN·mVx=ω1x+x2(ω2-ω1)/2hP-N1=65.68kN(4)右侧墙(图L-09)ω1=1.4eP1=21.28kN/m2ω2=1.4eP2=61.18kN/m2x=hP/2Nx=N4=375.82kNMx=ME+N1'x-ω1·x2/2-x3(ω2-ω1)/6hP=-307.04kN·mVx=ω1x+x2(ω2-ω1)/2hP-N1'=-5.41kN(5)中间墙(图L-10)x=hP/2Nx=N5=-727.84kNMx=MBD+(N1+N1')x=128.42kN·m图L-08图L-0