This paper presents a numerical study concerning light rail (LR) bridges, with emphasis on the characterisation of load effects and the interaction between LR loadings and supporting structures. The predicted bridge responses were employed to appraise the provisions of the Association of State Highway and Transportation Officials (Aashto) load and resistance factor design (LRFD) bridge design specifications (BDS) and the American Railway Engineering and Maintenance-of-Way Association manual. Because existing methods to determine live load distributions and skew correction factors are inadequate for LR bridges, new design equations are proposed. A single multiple presence factor of 1·0 is recommended for LR bridges, regardless of loaded tracks. The centrifugal force of curved bridges decays as the radius of curvature increases due to a change in centrifugal acceleration. Regarding the longitudinal force resulting from train braking, multipliers are suggested for design provisions. Temperature-induced loading is distributed to the bridge girders. Rail break is expected up to 75 mm within the range of thermal loading specified in Aashto LRFD BDS, which leads to an increase in dynamic load allowance. The force transfer from superstructure to substructure is marginally influenced by bearing arrangement. A statistical test was conducted to comparatively assess the equivalency of the bridge responses related to the above-mentioned design parameters.

中文翻译：

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轻轨运输桥梁的荷载效应和相关力

本文提供了有关轻轨（LR）桥梁的数值研究，重点是载荷效应的表征以及LR载荷与支撑结构之间的相互作用。预测的桥梁响应被用来评估国家公路和运输官员协会（Aashto）的荷载和阻力系数设计（LRFD）桥梁设计规范（BDS）以及美国铁路工程和道路维护协会手册的规定。由于现有的确定活荷载分布和偏斜校正因子的方法不足以用于LR桥，因此提出了新的设计方程。对于LR桥，无论加载轨道如何，建议使用1·0的单个多重存在因子。弯曲桥的离心力由于离心加速度的变化而随着曲率半径的增加而衰减。关于列车制动产生的纵向力，建议使用倍增器进行设计。温度引起的载荷被分配到桥梁。在Aashto LRFD BDS中指定的热负荷范围内，预期钢轨断裂最大可达75毫米，这会导致动态负荷余量的增加。从上部结构到下部结构的力传递受轴承布置的影响很小。进行统计测试以比较评估与上述设计参数有关的电桥响应的等效性。温度引起的载荷被分配到桥梁。在Aashto LRFD BDS中指定的热负荷范围内，预期钢轨断裂最大可达75毫米，这会导致动态负荷余量的增加。从上部结构到下部结构的力传递受轴承布置的影响很小。进行统计测试以比较评估与上述设计参数有关的电桥响应的等效性。温度引起的载荷被分配到桥梁。在Aashto LRFD BDS中指定的热负荷范围内，预期钢轨断裂最大可达75毫米，这会导致动态负荷余量的增加。从上部结构到下部结构的力传递受轴承布置的影响很小。进行统计测试以比较评估与上述设计参数有关的电桥响应的等效性。