Abstract

A need exists to determine the fatigue life of multi-span continuous bridges in the design stage. It is difficult to conduct a full-scale fatigue test of a bridge, hence the simulation of bridge-vehicle interaction dynamics is important to estimate the fatigue life of bridges. The vehicles entering the bridge are random in nature. In the present study, the arrival time of the vehicles is considered a random variable following Poisson process to simulate the actual traffic. The bridge-vehicle coupled system equations have been derived wherein the vehicle arrival rate appears as random variable casting difficulty in obtaining a direct solution. The solution approach has been devised using Orthogonal Polynomial Expansion method. Response statistics so obtained for a multi-span continuous bridge has been used in fatigue life estimation involving crack initiation phase and crack propagation phase modifying conventional linear damage rule. The sequence of loading is also considered in the modified fatigue formulation. The effect of the vehicle speed, road surface irregularity and the arrival rate of the vehicle on fatigue life estimation of the bridge have been studied.

摘要

在设计阶段需要确定多跨连续桥的疲劳寿命。桥梁的全尺寸疲劳试验很难进行，因此桥车相互作用动力学的模拟对于估计桥梁的疲劳寿命很重要。进入桥梁的车辆本质上是随机的。在本研究中，车辆的到达时间被视为遵循泊松过程的随机变量来模拟实际交通。已经推导出了桥车耦合系统方程，其中车辆到达率在获得直接解时表现为随机变量铸造困难。求解方法是使用正交多项式展开方法设计的。如此获得的多跨连续桥的响应统计数据已用于疲劳寿命估计，包括裂纹萌生阶段和裂纹扩展阶段，修改传统的线​​性损伤规则。在修改后的疲劳公式中也考虑了加载顺序。研究了车速、路面不平整度和车辆到达率对桥梁疲劳寿命估计的影响。