钢桁腹-混凝土组合梁桥受弯性能分析

Analysis of bending behavior of steel truss-concrete composite girder bridge

基于欧拉-伯努利梁理论,分析钢桁腹-混凝土组合梁桥的受弯性能。考虑到腹杆在纵向的不连续性,通过对腹杆进行受力分析,将腹杆的受力等效为轴力和面内弯矩,分别作用在顶板和底板上。引入奇异函数建立梁挠曲的微分方程,根据支座边界条件和腹杆节点的位移协调方程求解出所有的未知系数,得到了顶板和底板在不同荷载下的挠曲函数以及腹杆的轴力。根据腹杆的轴力确定腹杆的破坏荷载以及破坏形式。最后通过ANSYS建立实体有限元模型,对比了不同腹杆倾角下顶板的挠度和腹杆轴力,计算结果与有限元结果误差在5%左右。说明该方法能计算在弯曲荷载下,任意点的挠度和所有腹杆的轴力,计算方法既简单又能满足精度要求。

Based on Euler-Bernoulli beam theory, the singular function is used to analyze the bending behavior of steel truss-concrete composite girder bridges. Due to the longitudinal discontinuity of steel truss web-concrete composite girder bridge, by analyzing the force of the web, the web is equivalent to a set of equal and opposite axial forces and in-plane bending moments acting on the top and bottom plates respectively. The singular function is used to establish the differential equation of the beam. All the unknown coefficients are solved according to the boundary conditions and the displacement coordination equation of the web nodes. The deflection function of the beam and the axial force of the web under different loads are obtained. The failure load and failure form of the web are studied. Finally, the solid finite element model is established by ANSYS. The deflection of the roof and the axial force of the web under different inclination angles of the web are compared. The calculation results are in agreement with the finite element analysis.