1、孔径及净空净跨径L 0 = 1.9m 净高h 0 =2m孔数m=12、设计安全等级二级结构重要性系数r 0 = 1.03、汽车荷载荷载等级公路 —Ⅱ级4、填土情况涵顶填土高度H =7.3m 土的内摩擦角Φ =30°填土容重γ1 =19kN/m 3地基容许承载力[σ0] =300kPa5、建筑材料普通钢筋种类HRB400主钢筋直径25mm 钢筋抗拉强度设计值f sd =330MPa涵身混凝土强度等级C 25涵身混凝土抗压强度设计值f cd =11.5MPa 涵身混凝土抗拉强度设计值f td = 1.23MPa 钢筋混凝土重力密度γ2 =25kN/m 3基础混凝土强度等级C 20混凝土重力密度γ3 =23.5kN/m 3(一)截面尺寸拟定 (见图L-01)顶板、底板厚度δ =0.5m C 1 =0.5m钢 筋 混 凝 土 箱 涵 结 构 设 计一 、 设 计 资 料二 、 设 计 计 算侧墙厚度t =0.6m C 2 =0.6m 横梁计算跨径L P = L 0+t = 2.5m L = 3L 0+4t =8.1m 侧墙计算高度h P = h 0+δ = 2.5m h = h 0+2δ =3m 基础襟边 c =0m 基础高度 d =0m 基础宽度 B =8.1m(二)荷载计算1、恒载恒载竖向压力p 恒 = γ1H+γ2δ =151.20kN/m 2恒载水平压力顶板处e P1 = γ1Htan 2(45°-φ/2) =46.23kN/m 2图 L-01底板处e P2 = γ1(H+h)tan 2(45°-φ/3) =65.23kN/m 22、活载汽车后轮着地宽度0.6m，由《公路桥涵设计通用规范》(JTG D60—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>1.3/2m >1.8/2m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°= 4.315 m >1.4/2m故b = 1.400m ∑G =140kN 车辆荷载垂直压力q 车 = ∑G/(a³b) =32.26kN/m 2车辆荷载水平压力e 车 = q 车tan 2(45°-φ/2) =10.75kN/m 2(三)内力计算1、构件刚度比4.51 m0.6/2+Htan30°=K = (I1/I2)³(h P/L P) =0.58u=2K+1= 2.162、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M aA = M aC = M aE = M aF =-1/u²pL P2/12M BA = M BE = M DC = M DF =-(3K+1)/u²pL P2/12M BD = M DB =0横梁内法向力N a1 = N a2 = Na1' = Na2'=0侧墙内法向力N a3 = N a4 =(M BA-M aA+pL p2/2)/LpNa5=-(N a3+N a4)恒载p = p恒 =151.20kN/m2M aA = M aC = M aE = M aF =-36.50kN²mM BA = M BE = M DC = M DF =-99.87kN²mN a3 = N a4 =163.65kNNa5=-327.30kN车辆荷载p = q车 =32.26kN/m2M aA = M aC = M aE = M aF =-7.79kN²m图 L-02M BA = M BE = M DC = M DF =-21.31kN²mN a3 = N a4 =34.91kNNa5=-69.83kN(2)b种荷载作用下 (图L-03)M bA = M bC = M bE = M bF =-K²ph P2/6uM BA = M BE = M DC = M DF =K²ph P2/12uM BD = M DB =0N b1 = N b2 = Nb1' = Nb2'=ph P/2N b3 = N b4 =(M BA-M bA)/L pN b5=-(N b3+N b4)恒载p = e P1 =46.23kN/m2M bA = M bC = M bE = M bF =-12.92kN²mM BA = M BE = M DC = M DF = 6.46kN²m图 L-03N b1 = N b2 = N b1' = N b2'=57.79kNN b3 = N b4 =-7.75kNN b5=15.50kN(3)c种荷载作用下 (图L-04)Φ=20u(K+6)/K=490.51M cA = M cE =-(8K+59)²ph P2/6ΦM cC = M cF =-(12K+61)²ph P2/6ΦM BA = M BE =(7K+31)²ph P2/6ΦM DC = M DF =(3K+29)²ph P2/6ΦM BD = M DB =0N c1 = N c1'=ph P/6+(M cC-M cA)/h PN c2 = N c2'=ph P/3-(M cC-M cA)/h PN c3 = N c4 =(M BA-M cA)/L pN c5 =-(N c3+N c4)恒载p = e P2-e P1 =19.00kN/m2M cA = M cE =-2.57kN²mM cC = M cF =-2.74kN²mM BA = M BE = 1.41kN²m图 L-04M DC = M DF = 1.24kN²mN c1 = N c1'=7.85kNN c2 = N c2'=15.90kNN c3 = N c4 = 1.59kNN c5 =-3.19kN(4)d种荷载作用下 (图L-05)Φ1=20(K+2)(6K2+6K+1)=334.28Φ2=u/K= 3.73Φ3=120K3+278K2+335K+63=373.22Φ4=120K3+529K2+382K+63=484.48Φ5=360K3+742K2+285K+27=510.20Φ6=120K3+611K2+558K+87=637.80M dA =(-2/Φ2+Φ3/Φ1)²ph P2/4M dE =(-2/Φ2-Φ3/Φ1)²ph P2/4M dC =-(2/Φ2+Φ5/Φ1)²ph P2/24M dF =-(2/Φ2-Φ5/Φ1)²ph P2/24M BA =-(-2/Φ2+Φ4/Φ1)²ph P2/24M BE =-(-2/Φ2-Φ4/Φ1)²ph P2/24M DC =(1/Φ2+Φ6/Φ1)²ph P2/24M DF =(1/Φ2-Φ6/Φ1)²ph P2/24M BD =-Φ4²ph P2/12Φ1M DB =Φ6²ph P2/12Φ1N d1 =(M dC+ph P2/2-M dA)/h P图 L-05N d2 =ph p-N d1N d1' =(M dF-M dE)/h PN d2' =ph p-N d1'N d3 =(M BA+M BD-M dA)/L PN d4 =(M BE+M BD-M dE)/L PN d5 =-(N d3+N d4)车辆荷载p = e车 =10.75kN/m2M dA =9.74kN²mM dE =-27.77kN²mM dC =-5.78kN²mM dF = 2.77kN²mM BA =-5.56kN²mM BE = 2.56kN²mM DC = 6.09kN²mM DF =-4.59kN²mM BD =-8.12kN²mM DB =10.69kN²mN d1 =-19.65kNN d2 =46.53kNN d1' =0.09kNN d2' =26.80kNN d3 =-9.37kNN d4 =8.88kNN d5 =0.48kN(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》(JTG D60—2004)第4.1.6条进行承载能力极限状态效应组合3、构件内力计算(跨中截面内力)(1)顶板1 (图L-06)x =L P/2P = 1.2p恒+1.4q车 =226.60kNN x = N1 =64.39kNM x = M A+N3x-Px2/2 =39.63kN²mV x = Px-N3 =59.73kN顶板1'x =L P/2P = 1.2p恒+1.4q车 =226.60kNN x = N1' =92.01kNM x = M E+N4x-Px2/2 =19.05kN²mV x = Px-N4 =34.17kN(2)底板2 (图L-07)ω1 =1.2p恒+1.4(q车+3e车H P2/4L P2)=237.89kN/m2ω2 =1.2p恒+1.4q车=226.60kN/m2x =L P/2N x = N2 =168.32kNM x =M C+N3x-ω2²x2/2-5x3(ω1-ω2)/12L P=13.98kN²mV x =ω2x+3x2(ω1-ω2)/2L P-N3=70.31kN底板2'ω1 =1.2p恒+1.4q车=226.60kN/m2ω2 =1.2p恒+1.4(q车-3e车H P2/4L P2)=215.31kN/m2x =L P/2图 L-07图 L-06N x = N2' =140.69kNM x =M F+N4x-ω2²x2/2-x3(ω1-ω2)/6L P=68.92kN²mV x =ω2x+x2(ω1-ω2)/2L P-N4=27.12kN(3)左侧墙 (图L-08)ω1 =1.4e P1+1.4e车=79.78kN/m2ω2 =1.4e P2+1.4e车106.38kN/m2x =h P/2N x = N3 =223.52kNM x =M A+N1x-ω1²x2/2-x3(ω2-ω1)/6h P=-48.05kN²mV x =ω1x+x2(ω2-ω1)/2h P-N1=43.65kN(4)右侧墙 (图L-09)ω1 = 1.4e P1 =64.73kN/m2ω2 = 1.4e P2 =91.33kN/m2x =h P/2N x = N4=249.08kNM x =M E+N1'x-ω1²x2/2-x3(ω2-ω1)/6h P=-54.28kN²mV x =ω1x+x2(ω2-ω1)/2h P-N1'=-2.79kN(5)中间墙 (图L-10)x =h P/2N x = N5=-472.60kNM x =M BD+(N1+N1')x=184.14kN²m 图 L-08图 L-09V x =-(N1+N1')图 L-10=-156.40kN(5)构件内力汇总表(四)截面设计1、顶板(A-B\B-E)钢筋按左、右对称，用最不利荷载计算。