简化建模方法对空心板桥力学性能的影响

Effect of Simplified Modeling Method on Mechanical Performance of Hollow Slab Bridge

为研究简化建模方法对分析空心板桥受力特性的影响,以20 m装配式空心板桥为背景,考虑空心板横向连接及桥面铺装参与受力,运用ANSYS建立空心板桥的梁壳组合和铰接梁2种有限元模型,分析空心板桥动力特性、静载响应及车桥耦合振动响应,并将数值结果与试验对比。研究结果表明,梁壳组合模型的一、二阶频率与实测值更为接近;单车荷载作用下,各片梁跨中应变和位移横向变化,梁壳组合模型与实测值更吻合;承载能力等效荷载作用下,桥面铺装、混凝土企口缝与空心板桥共同参与受力,空心板桥未出现裂缝,且跨中位移和应变横向变化,梁壳组合模型与实测值更接近;跨中理论位移冲击系数,铰接梁模型大于梁壳组合模型,实测冲击系数与梁壳组合模型更接近。梁壳组合模型能体现空心板桥的桥面铺装及混凝土企口缝参与受力。新桥设计时,建议空心板桥适当考虑桥面铺装及混凝土企口缝参与受力。

In order to study the effect of simplified methods on analyzing mechanical performance of hollow slab bridge,Taking the 20 m span fabricated hollow slab bridge as research background,considering mutual effect of the lateral connection of hollow slabs and bridge deck pavement,the beam shell composite FE model and hinged girder FE model of hollow slab bridge are established by ANSYS. The dynamic characters of the hollow slab bridge,the responses of static load and vehicle-bridge coupling vibration are analysed and compared with test result. The result shows that（ 1） The first and the second frequencies by beam shell composite model are more close to the measured values.（ 2） In terms of the lateral variation of strains and displacements of different beam at mid-span of the hollow slab bridge under a vehicle load,the values by beam shell composite model are consistent with the measured values.（ 3） Under the action of equivalent load of bearing capacity,deck pavement and concrete rabbet bear load with hollow slab bridge and cracks are not appeared concurrently. In terms of the lateral variation of strains and displacements at mid-span,the values by beam shell composite model are more close to the measured values.（ 4） In terms of theoretical displacement impact coefficient of mid-span,the value of hinged girder model is larger than that of beam shell composite model,the values by beam shell composite model are more close to the measured values.（ 5） The beam shell composite model embodies that deck pavement and concrete rabbet will bear imposed load withhollow slab bridge. It is suggested to consider the contribution of deck pavement and concrete rabbet to the mechanical performance of the hollow slab bridge properly in design.