基于等效刚度的钢桁梁拱桥简化计算方法研究

钢桁梁拱桥作为一种适用于城轨合建的高次超静定结构, 在概念设计阶段用传统力学方法难以求解。为解决该问题, 文章通过对结构进行力学简化, 提出一种钢桁架梁等效抗弯刚度计算方法, 再根据膜张力假定计算简化梁拱组合体系的挠度、吊杆力, 解决了梁端转角的计算问题。结果表明: 理论解与有限元解吻合较好, 采用等效抗弯刚度法计算钢桁架梁的内力、挠度是可行的; 按照等效抗弯刚度求解简化梁拱组合体系的挠度、吊杆力和转角可以满足概念设计估算精度要求, 能够为设计者提供理论依据。

As a kind of high-order statically indeterminate structure suitable for integrated construction of urban road and rail transit, steel truss beam arch bridge is difficult to be solved by traditional mechanical methods in the conceptual design stage. In order to solve this problem, a calculation method of equivalent flexural stiffness of steel truss beams is proposed by simplifying the mechanics of the structure, and then the deflection and boom force of the composite beam and arch system are simplified according to the film tension assumption, and the calculation of beam end angle is solved. The results show that the theoretical solution is in good agreement with the finite element solution, and it is feasible to calculate the internal force and deflection of steel truss beams by using the equivalent flexural stiffness method. Solving the deflection, boom force and angle of the simplified beam-arch combination system according to the equivalent flexural stiffness can meet the accuracy requirements of conceptual design estimation, and can provide theoretical basis for designers.