特重车荷载下装配式PC板桥荷载效应分析

 为研究特重车荷载作用下PC 板桥的荷载效应,以河北省宣大高速公路WIM 数据为基础,共提取出883 个特重车荷载工况,使用“随机车流-桥梁耦合振动分析系统”计算各工况作用下PC 板桥各片板的最不利正弯矩效应及PC 板桥的最大正弯矩效应。通过对PC 板桥横向各片板最不利正弯矩效应的统计分析研究其横向受力性能,通过最大正弯矩效应与设计荷载效应的对比,分析PC 板桥的特重车正弯矩效应超限情况。结果发现:由于特重车在桥面鲜明的分布特点,PC 板桥1^#板的最不利正弯矩效应极值最大,而5^#板最不利正弯矩效应的均值最大,在特重车荷载作用下,PC 板桥正弯矩效应超限情况普遍,且部分工况最大正弯矩效应已超越设计荷载效应的1.8 倍,随着跨径的增加,PC 板桥正弯矩效应的超限工况数量、超限程度呈现下降趋势,但降幅并不明显。

Load effect analysis of PC slab bridges under extra-heavy trucks

For the purpose of studying the load effect of PC slab bridges under extra-heavy trucks, 883 extra-heavy truck scenarios were extracted based on WIM data from Xuanda highway in Hebei Province. The "bridge dynamic analysis system" was used to calculate the most unfavorable sagging moment of each slab and the maximum sagging moment effect of the bridge. The lateral performance of the slabs was investigated using statistics about the most unfavorable sagging moment of each slab. In addition, the overrun of sagging moment of PC slab bridges was analyzed based on comparison of the maximum sagging moment effect and design value. The results show that owing to the apparent distribution characteristics of extra-heavy trucks, the extreme unfavorable sagging moment of slab 1 was the highest, and the average unfavorable sagging moment of slab 5 was the highest. Under extra-heavy truck load, the overrun problem of sagging moment was universal. Besides, the maximum sagging moment of some scenarios was 1.8 times of the design value. Both the quantity of overrun scenarios and overrun level decreased slightly with the increase of bridge span.