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=16.2m净高h0=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C3015~506.箱涵尺寸顶板、底板厚度δ=1.2m倒角C1=0.5m侧墙厚度t=1.5m倒角C2=1.5m基础襟边c=0.2m基础高度d=0.5m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=16.2m净高h0=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=1.2mC1=0.5m侧墙厚度t=1.5mC2=1.5m横梁计算跨径LP=L0+t=17.7mL=2L0+3t=36.9m侧墙计算高度hP=h0+δ=6.2mh=h0+2δ=7.4m基础襟边c=0.2m基础高度d=0.5m基础宽度B=37.3m(二)荷载计算1、恒载恒载竖向压力p恒=γ1H+γ2δ=39.90kN/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)=47.70kN/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=(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)=0.18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5页，共28页u=2K+1=1.362、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=39.90kN/m2MaA=MaC=MaE=MaF=-766.69kN·mMBA=MBE=MDC=MDF=-1179.19kN·mNa3=Na4=329.81kNNa5=-659.62kN车辆荷载p=q车=66.13kN/m2MaA=MaC=MaE=MaF=-1270.72kN·mMBA=MBE=MDC=MDF=-1954.41kN·mNa3=Na4=546.63kNNa5=-1093.26kN(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=-2.79kN·mMBA=MBE=MDC=MDF=1.40kN·m图L-03Nb1=Nb2=Nb1'=Nb2'=10.23kNNb3=Nb4=-0.24kNNb5=0.47kN(3)c种荷载作用下(图L-04)Φ=20u(K+6)/K=936.28McA=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=44.40kN/m2McA=McE=-18.36kN·mMcC=McF=-19.19kN·mMBA=MBE=9.80kN·m图L-04MDC=MDF=8.97kN·mNc1=Nc1'=45.75kNNc2=Nc2'=91.89kNNc3=Nc4=1.59kNNc5=-3.18kN(4)d种荷载作用下(图L-05)Φ1=20(K+2)(6K2+6K+1)=98.90Φ2=u/K=7.58Φ3=120K3+278K2+335K+63=132.71Φ4=120K3+529K2+382K+63=149.22Φ5=360K3+742K2+285K+27=104.06Φ6=120K3+611K2+558K+87=207.42MdA=(-2/Φ2+Φ3/Φ1)·phP2/4MdE=(-2/Φ2-Φ3/Φ1)·phP2/4MdC=-(2/Φ2+Φ5/Φ1)·phP2/24第6页，共28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=228.34kN·mMdE=-340.19kN·mMdC=-46.47kN·mMdF=27.83kN·mMBA=-62.59kN·mMBE=43.95kN·mMDC=78.71kN·mMDF=-69.39kN·mMBD=-106.54kN·mMDB=148.09kN·mNd1=-112.66kNNd2=249.33kNNd1'=-2.60kNNd2'=139.27kNNd3=-22.46kNNd4=15.68kNNd5=6.77kN(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MAMEMCMFMBAMBEMDCMDFMBD-766.69-766.69-766.69-766.69-1179.19-1179.19-1179.19-1179.190.00-920.02-920.02-920.02-920.02-1415.03-1415.03-1415.03-1415.030.00-2.79-2.79-2.79-2.791.401.401.401.400.00-18.36-18.36-19.19-19.199.809.808.978.970.00-29.61-29.61-30.77-30.7715.6715.6714.5214.520.00-1270.72-1270.72-1270.72-1270.72-1954.41-1954.41-1954.41-1954.410.00228.34-340.19-46.4727.83-62.5943.9578.71-69.39-106.54-1459.33-2255.27-1844.06-1740.05-2823.80-2674.65-2625.98-2833.31-149.15-2408.97-3204.91-2794.85-2690.84-4223.15-4074.00-4026.50-4233.83-149.15N1N2N1'N2'N3N4N50.000.000.000.00329.81329.81-659.620.000.000.000.00395.77395.77-791.5410.2310.2310.2310.23-0.24-0.240.4745.7591.8945.7591.891.591.59-3.1878.37142.9778.37142.971.901.90-3.790.000.000.000.00546.63546.63-1093.26-112.66249.33-2.60139.27-22.4615.686.77-157.72349.06-3.64194.98733.85787.24-1521.09-79.36492.0374.73338.01131.51184.9-2316.423、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M(kN·m)ad1.4×∑汽车荷载效应组合车辆荷载N(kN)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荷载种类恒载a1.2×∑结构、土的重力bc1.4×∑土侧压力第7页，共28页P=1.2p恒+1.4q车=140.46kNNx=N1=-79.36kNMx=MA+N3x-Px2/2=2104.22kN·mVx=Px-N3=111.59kN顶板1'x=LP/2P=1.2p恒+1.4q车=140.46kNNx=N1'=74.73kNMx=ME+N4x-Px2/2=1780.83kN·mVx=Px-N4=58.19kN(2)底板2(图L-07)ω1=1.2p恒+1.4(q车+3e车HP2/4LP2)=143.30kN/m2ω2=1.2p恒+1.4q车=140.46kN/m2x=LP/2Nx=N2=492.03kNMx=MC+N3x-ω2·x2/2-5x3(ω1-ω2)/12LP=1671.99kN·mVx=ω2x+3x2(ω1-ω2)/2LP-N3=130.44kN底板2'ω1=1.2p恒+1.4q车=140.46kN/m2ω2=1.2p恒+1.4(q车-3e车HP2/4LP2)=137.62kN/m2x=LP/2Nx=N2'=337.95kNMx=MF+N4x-ω2·x2/2-x3(ω1-ω2)/6LP=2387.57kN·mVx=ω2x+x2(ω1-ω2)/2LP-N4=45.62kN(3)左侧墙(图L-08)ω1=1.4eP1+1.4e车=35.48kN/m2ω2=1.4eP2+1.4e车97.64kN/m2x=hP/2Nx=N3=1131.51kNMx=MA+N1x-ω1·x2/2-x3(ω2-ω1)/6hP=-2875.24kN·mVx=ω1x+x2(ω2-ω1)/2hP-N1=237.52kN(4)右侧墙(图L-09)ω1=1.4eP1=4.62kN/m2ω2=1.4eP2=66.78kN/m2x=hP/2Nx=N4=1184.91kNMx=ME+N1'x-ω1·x2/2-x3(ω2-ω1)/6hP=-3045.24kN·mVx=ω1x+x2(ω2-ω1)/2hP-N1'=-12.23kN(5)