Seismic behavior prediction and post-earthquake performance evaluation of bridge superstructures

1995年神户地震的一份报告表明，梁端的撞击损伤和支架的失效会阻碍救援工作的交通。为了准确分析桥梁在碰撞作用下的行为，评价桥梁碰撞缓减措施的有效性，建立了包括碰撞缓减装置在内的桥梁整体结构的三维模型。尤其是在地震作用下，桥梁主梁/桥面的脱落对桥梁的安全性和使用性能造成了极大的危害。最近几次强烈地震的证据表明，除了纵向上的破坏外，碰撞引起的桥梁横移和转动也会导致脱座，为了分析这种影响，在研究的前半部分建立了碰撞的三维模型。此外，为了准确分析碰撞效应，还需要对整个桥梁结构进行三维建模。本研究提出了一种考虑摩擦的桥梁主梁三维碰撞问题模型。通过撞击实验对该模型进行了验证。还采用了全桥结构的三维非线性模型。编制了桥梁动力分析通用程序，并对某三跨钢桥进行了碰撞计算。用计算结果说明了碰撞模型的适用性。然后，在研究的后半部分，选取了三跨钢结构高架桥进行了实例分析。此外，还利用梁间最大间隙大小和支座最大相对位移进行了使用性能评估。

A report of 1995 Kobe earthquake showed that impact damage at ends of girders and fails of supports can impede traffics of rescue works. To precisely analyze the behaviors of bridges with poundings and evaluate the effectiveness of pounding mitigation measures, a 3D model for whole bridge structures including pounding and pounding mitigation devices is constructed. Especially, unseating of bridge girders/decks during earthquakes is very harmful to the safety and serviceability of bridges. Evidence from recent severe earthquakes indicates that in addition to damage along longitudinal direction, lateral displacement and rotation of bridge girders caused by pounding can also lead to unseating.To analyze this effect, a 3D model of pounding is constructed at the first half of the research. In addition, for a precise analysis of pounding effects, 3D modeling of whole bridge structures is also in demand. This research presents a model for 3D pounding problems of bridge girders with friction. Experiments of pounding were conducted to verify this model. 3D nonlinear models of whole bridge structures have also been adopted. A general-purpose dynamic analysis program for bridges and conducts computations of pounding among a three-span steel bridge has been implemented. The applicability of the pounding model is illustrated with the results. Then, at the last half of the research, three-span steel elevated bridge has been chosen for a case study. In addition, the peak gap size between girders and maximum relative displacements of supporters are employed for serviceability evaluation.