随机车流作用下多塔斜拉桥总体荷载响应特性

Overall Vehicle Load Response Characteristic of Multi span Cable stayed Bridge Under Stochastic Traffic Flow

摘要:

结合车辆荷载研究技术，以三塔斜拉桥为例，分析了该结构在随机车流作用下的总体荷载响应特性，深入研究了实际汽车荷载响应与规范荷载模型计算值差别，探讨了车流随机特性参数对结构响应特性影响.结果表明：我国《公路桥涵设计通用规范》（JTG D60—2004）的汽车荷载模型对多塔斜拉桥估计过高，交通运营状态和日均交通量、重车混入率交通特性等参数对汽车荷载响应影响显著，对不平衡加载敏感不同的效应显示出对随机车流不同的响应特性.说明现有规范基于影响面确定加载范围的极端加载方式及荷载取值无法反映多塔斜拉桥的实际汽车荷载响应状况，建立反映实际状况的荷载模型可考虑引入多参数多级别的性能设计思想.

Abstract:

A case study was made of a three pylon cable stayed bridge to investigate the overall vehicle load response of multi span cable stayed bridge under stochastic traffic flow by resorting to the advanced vehicle load research technology, and the differences between the actual and design load responses were also compared. Results show that the current bridge criterion (JTG D60—2004) overvalues the vehicle load response for multi span cable stayed bridge; parameters such as traffic condition and traffic properties of average daily traffic volume and truck ratio affect the response indirectly; different load effects present different sensitiveness to stochastic traffic flow. The results indicate the current load model cannot reflect the actual vehicle load responses in load value as well as loading range, thus, multi parameter and multi level performance based design can be taken into consideration to establish load model reflecting actual traffic condition.