特重车交通荷载作用下大跨拱桥动力响应分析

摘要

为研究特重车交通荷载工况作用下大跨拱桥的动力响应特点，以河北省宣大高速公路上某大桥的动态称重系统所采集的近3年的交通数据为基础，定义并提取了特重车的交通荷载工况，进而分析了不同类型特重车交通荷载工况所占比例及每个特重车交通荷载工况车辆总质量的分布规律。利用随机车流-桥梁耦合振动分析软件计算了大跨拱桥在特重车交通荷载作用下的空间动力响应，并与新旧桥梁规范中的设计车辆荷载对应的响应进行了对比。结果表明：新规范对拱桥关键部位的设计荷载定义更为保守，实测的交通荷载工况中仅有极少数特重车交通荷载工况对应的响应超过了设计车辆荷载对应的响应；对于该大跨拱桥，新桥梁规范中的设计车辆荷载能够较充分地考虑大部分特重车交通荷载作用对桥梁结构整体受力产生的不利影响。%Authors investigated the characteristics of the spatial dynamic response of an long-span arch bridge using the random traffic-bridge coupling vibration analysis software based on realistic extra-heavy truck load data recorded by the weigh-in-motion (WIM ) system . A set of WIM system was installed on a bridge located in the highway from Xuanhua to Datong , Hebei Province .The extra-heavy truck load cases were defined and extracted using traffic load data in last three years acquainted by the system ,then the proportions of different types and the vehicle weight distributions of the extra-heavy truck cases were analyzed ,and the structure response was compared with that under the design specification load .The spatial dynamic response of long-span arch bridge under the extra-heavy truck cases was analyzed using the random traffic-bridge coupling vibration analysis software ,and the structure response was compared with that under the design vehicle load in old and current bridge codes .The results show that only few extra-heavy truck cases result in larger response than those under design specification vehicle load , implying that the designed load specified in the code can take into account of most critical traffic cases for the studied long-span arch bridge .