简要地介绍了我国铁路桥梁的现状和解放以来的发展历程，论述了既有桥梁提速后出现的问题以及解决问题的对策、高速铁路桥梁的特点和设计要求，最后对新世纪铁路桥梁的几个主要发展方向的前景做了评述。

基于蠕滑理论，研究了单个轮对和整车在轨道不平顺和桥梁振动激励下的横向运动规律。得到轨道方向不平顺作用下轮对横向运动微分方程的解析解。分析表明，根据几何学推导的自由轮对蛇行运动解是轮对简化运动微分方程的 齐次解，而轮对所经过的轨道方向不平顺是其特解。齐次解将因阻尼而很快衰减，而特解则决定了系统稳态响应特征。采用整车模型的车桥动力仿真计算也表明在不发生蛇行失稳的正常运营车速下，轮对运动轨迹有沿着轨道方向不平顺的趋势，轮轨横向相互作用力主要受轨道不平顺影响，桥梁振动和蠕滑系数在正常范围内的波动对车桥横向振动影响较小。

A new framework is proposed for analyzing vehicle-bridge/track system dynamical interaction. This framework is based on mode superposition and pseudo force iteration. Both the finite element(FE) models of vehicles and bridge/track structures are established separately by universal software, through which the eigenvalue analysis is carried out to get corresponding eigenvalues and eigenvectors. So motion differential equations of these vehicle and bridge/track models can be set up using mode superposition method. This leads to less effort to form equations of motion for vehicles and less computing time to solve the system responses. Together with mode superposition method, pseudo force iteration method is utilized to handle non-proportional damping, material nonlinearity problem as well as wheel-rail contact relationship. Owing to the iterative method, two kinds of wheel-rail contact condition, i.e. no-jump condition and jump condition, are easily compatible in this framework. The versatility of this framework rests with its compatibility for arbitrary vehicle types, arbitrary bridge-track elements, almost most material nonlinearity and optional wheel-rail contract condition.

根据车桥耦合振动理论，结合下承式钢板梁桥构造，提出采用最佳下平纵联尺寸的加固方法，提高钢板梁桥刚度，改善桥梁横向振动。对沪宁线#165A桥加固分析的结果表明，当下平纵联杆件截面尺寸增至4倍时，桥梁横向刚度明显提高，横向振动得到有效抑制。研究还发现，对下承式钢板梁的加固不宜采用主梁加固方式。

基于轮轨滚动接触蠕滑理论和准定常抖振力，建立风-车-桥系统空间耦合振动分析模型并编制相应的计算程序。研究不同车速、不同风速下轻轨列车通过大跨度斜拉桥的走行性。结合列车走行特性，对列车各项安全性评定标准进行了具体分析。研究表明将轮重减载率作为强风作用下列车运行安全性评定标准的是不合适的。建议将倾覆系数作为强风作用下列车运行安全性主要评定标准。