大跨径低刚度钢桥面铺装三维仿真力学分析

Three-Dimension Simulation Mechanical Analysis of Deck Pavementof Long-Span and Low-Stiffness Steel Bridge

为研究大跨径低刚度钢桥在不同铺装方案下的力学响应状态,采用Midas/civil软件建立了武汉某长江大桥全桥有限元模型,采用ANSYS软件建立了GA+SMA和三层EA铺装方案的三维仿真模型,分析了该桥主桥跨中的挠曲变形,以及2种铺装方案在162个荷载工况下的弯拉应变和层间剪应力。研究结果表明:随着重载交通量的增加,该桥跨中存在较大的挠动,最大挠度值达到1.02 m,为初始设计值的132.5%;在最不利荷载组合下,铺装体系刚度对组合结构弯拉应变和层间剪应力均有显著的影响,铺装体系刚度大,则纵向最大弯拉应变大,横向最大弯拉应变和层间最大剪应力小;2种铺装方案的横向最大弯拉应变和纵向最大弯拉应变均呈现铺装表面>铺装层间>顶板表面,铺装表面横向最大弯拉应变>铺装表面纵向最大弯拉应变,层间最大剪应力总体呈现铺装层间>顶板表面;大跨径低刚度钢桥在进行组合结构疲劳开裂和层间脱层推移指标设计时,宜将铺装层表面横向最大弯拉应变和防水层黏结抗剪强度作为控制指标,并通过组合结构疲劳开裂试验和剪切疲劳试验,以确定不同铺装方案的适应性,以及材料和组合结构指标要求。

In order to study the mechanical response of long-span and low-stiffness steel bridge with different pavement schemes,Midas/civil software was used to establish the finite element model of a certain Yangtze River Bridge in Wuhan,and ANSYS software was used to establish the three-dimensional simulation model of GA+SMA and tri-layer EA pavement scheme.Then,flexural deformation of the main span of the proposed bridge was analyzed,and flexural-tensile strain and interlaminar shear stress of the two pavement schemes under 162 load conditions were calculated.The research results show that:with the increase of heavy traffic volume,there is a large deflection in the mid-span of the bridge,and the maximum deflection reaches 1.02m,which is 132.5%of the initial design value.Under the most adverse load combination,the stiffness of pavement system has a significant impact on the flexural-tensile strain and interlaminar shear stress of the composite structure.In general,the greater the stiffness of pavement system,the greater the longitudinal maximum flexural-tensile strain,and the smaller the transverse maximum flexural-tensile strain and the interlaminar maximum shear stress.The transverse maximum flexural-tensile strain and longitudinal maximum flexural-tensile strain of pavement surface,interlayer and roof surface of the two pavement schemes show a decreasing trend.In addition,the transverse maximum flexural strain is greater than the longitudinal maximum flexural strain of pavement surface.The interlaminar shear stress of interlayer and steel deck surface of the two pavement schemes show a decreasing trend.The transverse maximum flexural-tensile strain of pavement surface and shear strength of waterproof layer should be taken as control indexes,and the fatigue cracking test and shear fatigue test of composite structure should be carried out to determine the adaptability of different pavement schemes and the requirements of material and composite structure indexes,in the design of fatigue cracking and interlaminar delamination displacement index of composite structure for long-span and low-stiffness steel bridge.