中文摘要：

偏载作用下大跨度桥梁主梁易产生较大的扭转变形，这对轨道交通车辆运行的安全性和舒适性是不利的。针对大跨度桥梁扭转变形的特点，明确了大跨度桥梁主梁局部扭曲和整体扭转两种变形形式，并结合相关规范的已有规定和公务部门的管理标准，提出了扭转变形限值的取值标准，并通过车-桥耦合振动分析实例验证了主梁扭转变形的不利影响。研究结论可为设计和管理人员提供参考。

英文摘要：

Eccentric loadings will induce large torsional deformations for the girders of long-span bridges, deteriorating the safety and comfort of moving vehicles of rail transit. According to their characteristics, torsional deformations of long-span bridges are classified into two types： local twist and bodily torsion. Based on the related specifications and railway management standards, the critical values for the torsional deformations are put forward. An example of coupled vibration of vehicle-bridge system is taken to identify the adverse effects of the torsional deformations of the girder.