Abstract: Traffic composition features and laws for a certain cross-sea bridge in service period were analyzed based on a month WIM data. The vehicle and motorcade load properties as well as the load transverse distribution laws of multi-lane were described. Taking the critical sections of the three-span cable stayed bridge with twin towers as research object, the effect distribution characteristics resulting from the actual traffic load were analyzed statistically, and these effect results were compared with the normal values of vehicle loads in current bridge design specification. Results indicate that the relationship between the average space headway or time headway and hourly traffic volume can be expressed by the binomial exponential function. Vehicle load level on various driving lanes presents significant difference because of the tendency of vehicle lane-choice of different axial vehicle. The maximum effect values of the heaviest driving lane exceed the corresponding code values, while those of multi-lane are on the contrary. In the end, the insufficiencies of the multi-lane reduction factor and the calculation mode of vehicle load on large-span bridge in the current specification were discussed and some suggestions were also provided.

Key words: bridge engineering, weigh-in-motion, traffic feature, vehicle load, long span bridge, effect analysis

摘要： 通过对某跨海大桥1个月的WIM数据进行统计，分析了运营阶段的交通组成特性及其规律，讨论了车辆荷载和车队荷载特性、多车道汽车荷载的横向分布规律。以该跨海大桥双塔三跨斜 拉桥结构的关键截面为分析对象，研究了在实测车流荷载作用下的效应分布特征，并与现行设计规范的汽车效应标准值进行对比。结果显示：车头间距和时距与小时交通量呈现出二项指数函 数关系；由于不同轴型车辆对行驶车道选择的倾向性，导致各车道汽车荷载水平分布存在明显的差异，单个重车车道效应极值大于规范值，而多车道总体效应小于规范值。探讨了现行规范在 多车道荷载折减问题和大跨径桥梁汽车荷载效应计算模式上的不足与建议。

关键词: 桥梁工程, 动态称重, 交通特性, 车辆荷载, 大跨径桥梁, 效应分析