预制装配式板梁桥的模型修正方法

为反映在役桥梁的实际状况,提出了板梁桥的模型修正方法.假设铰缝相对位移与铰缝剪力成正比,并将铰缝刚度、板梁抗弯刚度和板梁抗扭刚度均作为未知量进行修正.基于板梁边实测位移建立位移方程,并采用QR分解法得到矛盾方程组的最优解.模型考虑了多个静载试验工况、多个荷载及荷载偏心的特点,可以直接应用于桥梁荷载试验.对有防撞护栏和有损伤的板梁桥进行了数值模拟,结果表明:无论是板梁有较大损伤,还是有复杂附属结构,该修正方法均可给出准确的修正系数;试验应尽可能采用多个试验工况,并将荷载布置在被测试的铰缝和板梁附近. 

Model Updating Method for Prefabricated Multi-girder Bridges

In order to reflect the real status of an existing bridge, a new model updating method for multi-girder bridges was presented. In this method, the relative displacement in a hinge joint is supposed to be proportional to the shear force; the stiffness of hinge joint, flexural and torsional rigidity of girders are simultaneously taken as unknown parameters to be modified. The displacement equations are established with measured displacements on both sides of girders, and the optimal solution for the over-determined equations is obtained by the QR algorithm. The characters of multi-load cases, multi-loads and eccentric loads are considered in the proposed model, so that it can be used to bridge load tests. Numerical simulations for a multi-girder bridge with crash barriers and damages were carried out. The simulation results show that the proposed method can produce accurate corrected factors for girders with large damage or complex affiliated structures; load cases should be adopted as many as possible, and the loads should be arranged near the hinge joints or girders to be tested.