用于大跨度桥梁承载力评估的车辆荷载修正方法

Calibration Method of Traffic Load for Long-span Bridge Loading Carrying Capacity

为了对大跨度桥梁的承载能力进行合理评估,提出了一种基于现场交通流量调查信息的车辆荷载修正方法.将车质量概率密度分布等效为多峰正态分布,采用滤过Poisson随机过程模拟评估桥梁的车辆荷载效应,分析了平均日交通流量、车速和车辆类型组成比例对车辆荷载效应的影响.结果表明,不同交通状况下的车辆荷载效应与设计值相差很大.对设计基准期内的最大荷载效应进行了预测,给出了具有95%保证率下的车辆荷载修正系数.最后以某混凝土斜拉桥为例,详细阐述了该方法的使用过程.

To reasonably evaluate the loading carrying capacity of the concrete cable-stayed bridges,according to traffic survey,a method of traffic load calibration is proposed.The traffic weight is modeled as normal distribution with multi peak values,the traffic load response is modeled by the Poisson stochastic process,and the influences of average daily traffic,velocity,and the vehicles composition are discussed.There are large differences in the design traffic load responses with the real response under different traffic conditions.The calibration factor of 95% ascertains is obtained.Finally,the method is demonstrated by taking a certain bridge as an example.