Development of Nonlinear Models for the Earthquake Response of Railway Bridges

铁路桥是交通基础设施的重要组成部分。其中许多位于人口密集地区，地震风险高。这些结构的地震反应特征和性能的基本知识是重要的。铁路桥动力学的一个重要特征是轨道-道砟系统，它延伸到相邻的路基上，可能为结构提供额外的强度。最近对一座有碴铁路桥梁进行的动力试验揭示了铁路-砟系统动力相互作用的复杂性。在这个项目中，将使用现有的现场数据进行一系列的识别研究，以识别桥梁各元素的重要刚度参数。内华达大学对有载和无载系统进行的失效测试数据将用于开发失效元素并将其纳入非线性模型。所建立的模型将用于典型铁路桥梁在地震作用下的响应预测。对这些反应的研究将表明改造的需要。铁路桥梁是国家交通网络的重要组成部分，该项目将提高铁路桥梁非线性动力响应的建模能力。＊＊＊

9522125 Maragakis Railway bridges are a critical component of the transportation infrastructure. Many of them are located in densely populated areas with high seismic risk. A basic knowledge of the seismic response characteristics and performance of these structures is important. An important feature of railway bridge dynamics is the rail-ties-ballast system which extends over the adjacent roadbed and probably provides additional strength to the structures. A recent dynamic test of a ballasted railway bridge sheds some light into the complexity of the dynamic interaction involved in rail-ballast systems. In this project a series of identification studies will be performed by using the available field data in order to identify important stiffness parameters of various elements of the bridge. The data from the failure tests conducted at the University of Nevada on ballasted and unballasted systems will be used for the development of failure elements and their incorporation into nonlinear models. The developed models will be used for the prediction of the response of typical railway bridges to earthquake excitations. A study of these responses will indicate needs for retrofitting. This project will improve the capability of modeling the nonlinear dynamic response of railway bridges which are a critical component of the nation's transportation networks. ***