基于合成车流的桥梁车辆荷载效应极值预测

Extreme Value Extrapolation for Bridge Vehichle Load Effect Based on Synthetic Vehicle Flow

摘要:

车辆荷载是公路桥梁设计与评估过程中的关键问题之一，现有规范的车辆荷载取值适用于一般设计，对于精度要求更高的在役桥梁评估或桥梁关键构件设计，应结合实际车辆荷载特征，建立相应的车辆荷载模型.考虑我国现有大量静态车辆交通流数据的特点，提出了采用合成车流方法模拟交通流并实现荷载效应预测的方法，详细描述了基于合成车流的车辆荷载效应模拟方法，检验了Rice公式方法对于合成车流荷载效应极值预测的适用性，以此建立基于合成车流的车辆荷载效应模拟及其极值预测过程.最后，通过算例校验了合成车流荷载效应以及预测荷载效应极值的准确性，并简要对比了现有规范与本文方法在车辆荷载效应方面的差异.

Abstract:

Vehicle load is one of the key factors for bridge design and assessment. For accurate condition assessment or key components design, site specific vehicle load models based on real traffic conditions should be established. Since the static vehicle data in China cannot be used for weight in motion(WIM) data based methods directly, a synthetic vehicle flow based simulation method is proposed. Statistic models of vehicle data, and vehicle flow models are established on the basis of field measurement. The Gaussian and stationary assumption for using Rice’s formula to extrapolate characteristic value for long return period based on simulated vehicle loading effects processes is calibrated in mathematical way. An example is given to illustrate the difference of live load effect based on loading models derived by the existing Chinese design code and the proposed method in this study, and the accuracy of simulation and extrapolation are also checked.