大跨钢-混凝土结合梁斜拉桥传力机理

Mechanic Behavior of Steel-Concrete Composite Girder of Long-Span Cable-Stayed Bridge

为探讨大跨结合梁斜拉桥中钢主梁与混凝土板的传力机理,采用梁段模型试验与有限元数值分析相结合的方法,对观音岩长江大桥主梁的受力性能进行了研究.用有限元软件ANSYS建立标准梁段的空间有限元模型,对不同组合荷载作用下结合梁的应力分布进行了弹性分析;考虑材料的非线性特性和剪力钉荷载-滑移的非线性关系,对设计荷载组合下结合梁的力学行为进行了弹塑性分析.在此基础上,采用1∶2的缩尺比例进行模型试验研究,测试了不同荷载组合下结合梁截面的应力.研究结果表明:在设计荷载组合作用下,混凝土板与钢主梁间的相对滑移较小,剪力钉能有效抗剪,保证结构整体受力性能的要求;结合梁截面应力基本满足平截面假定,钢主梁以抗弯为主,混凝土板承担较大截面压力.

In order to investigate the mechanic behavior of steel-concrete composite girder in long-span cable-stayed bridge, finite element method （FEM） analysis and specimen test of Guanyinyan Yangtze River bridge were carried out. By using FEM program ANSYS, a 3D model for girder section was founded, and elastic analyses of stress distribution of composite girder under different load cases were performed. By considering the nonlinear material properties and nonlinear slip of shear stud, elastic- plastic behaviors of composite girder were analyzed. A test specimen for composite girder with a scale of 1 to 2 was designed, and its static load test was carried out. Stresses at test points in cross section of composite girder beating different load cases were obtained. The research results show that few relative slippage occurs between steel plate girder Shear studs are qualified to resist interface and concrete slab of composite girder bearing design load. shear and ensure a full composite action. The distribution of stresses in cross sections are similar to the assumption of plane cross-section. For the composite girder, steel girder mainly provides bending strength, while concrete slab provides compression strength mainly.