载重汽车桥梁伸缩缝跳车动力荷载计算方法与影响因素分析  

A computational method for the dynamic load in heavy-vehicle bumping at the bridge expansion joint and analysis of the influencing factors

作　　者：丁勇[1] 黄奇[1] 谢旭[2] 黄剑源[1] 

机构地区：[1]宁波大学,浙江宁波315211 [2]浙江大学,浙江杭州310027

出　　处：《土木工程学报》2013年第7期98-107,共10页China Civil Engineering Journal

基　　金：国家自然科学基金(50778160);近海冲击与安全工程浙江省重中之重学科开放基金(ZJ1109);浙江省自然科学基金(Y1110548)

摘　　要：为分析载重汽车在桥梁伸缩缝处跳车时的动力荷载,提出一种基于分布式弹簧-阻尼单元的计算方法,该方法考虑了车辆-路面的接触长度和车轮的动力特性。车轮通过伸缩缝的过程分3个阶段来模拟,分别为下伸缩缝、跨伸缩缝、上伸缩缝,结合车辆有限元动力学分析,实现对车轮经过伸缩缝时的竖向动荷载的定量研究。对载重汽车经过单缝式伸缩缝的实例分析表明:①由分布式弹簧-阻尼单元计算得到的轮底位移比以往文献中的假设值小得多,动力荷载也将减小;②载重汽车伸缩缝跳车时的轮载冲击系数可能超过中国、欧洲桥梁规范的设计值,需要引起重视;③跳车最大轮载与伸缩缝宽度成正比,可以用减小伸缩缝宽度的方法降低冲击系数;④降低车速并不一定能降低冲击系数,轮载最大冲击系数往往发生在中等车速时;⑤伸缩缝跳车的最大冲击荷载主要分布在伸缩缝旁,因此只需要对伸缩缝附近的局部结构进行加强。To analyze the dynamic load of heavy vehicle at the bridge expansion joint, a computational method based on spring-damping element is presented with the contact length between the tire and the road as well as the dynamic characteristics of the wheel considered. The process of the tire passing through the expansion joint is divided into three stages： going down, spanning and going up the expansion joint. Combined with the dynamic finite element analysis of the vehicle, the vertical dynamic load of the tire passing through the expansion joint could be calculated. As an example, the dynamic load of the heavy vehicle passing through the single-gap expansion joint is analyzed, the results indicate that： ① The calculated displacement at the bottom of the tire is much smaller than the values available in the literature, leading to a smaller tire load;② The impact factor of the tire load in heavy-vehicle bumping at expansion joint may be higher than the value provided by the Chinese or European design codes of bridge, and hence more attentions should be paid;③The maximum dynamic load is proportional to the width of the expansion joint, and hence the impact factor could be reduced by decreasing the gap width; ④Lower the vehicle speed may not lead to smaller impact factor at the bridge expansion joint, because the maximum impact factor usually occurs at a medium speed; ⑤The maximum dynamic load mainly occurs near the expansion joint, and hence it is only necessary to strengthen the local structure near the expansion joint.

关 键 词：桥梁工程 伸缩缝跳车 动力荷载 分布式弹簧-阻尼单元 冲击系数 

分 类 号：U442.5[建筑科学—桥梁与隧道工程]