实桥加载下钢桥面沥青铺装层应变动态响应

为获取钢桥面沥青铺装结构的实际力学响应情况,对上海市昌吉东路大桥进行梁式桥实桥加载试验,分析了沥青铺装层(沥青玛蹄脂与环氧沥青混合料)不同层位在匀速、刹车动载作用下的纵横向应变,研究表明,路表处应变最大,为最易破坏部位;同一测点应变在匀速及刹车时具有相同的响应状态;纵向动态应变具有压拉交替及波动特性,横向动态应变仅具有波动性;动态应变随深度、车速增大及轴重减小而呈减小趋势;同一层位横向应变大于纵向应变,且前者幅值较后者对影响因素更为敏感;动态应变及其幅值对轴重、车速的敏感程度均自上而下减小;动载瞬间应变与静载应变间差异视层位不同而异.结果可为后续钢桥面铺装结构设计及材料选择提供参考.

Strain Dynamic Response of Asphalt Pavement on Steel Deck Bridge with Field Loading Test

In order to obtain the actual mechanical response of asphalt pavement of steel deck bridge, a field loading test was carried out on Changji East Road Bridge in Shanghai, a steel bridge of the pavement with stone mastic asphalt and epoxy asphalt as the upper and the lower layers respectively. Test results show that the maximum strain appears at surface, where the pavement is the easiest to be damaged. The dynamic response of longitudinal and transverse strains under two loading conditions (uniform velocity and brake) was analyzed in different layers, and the response trends at the same measurement point had little discrepancy. Longitudinal dynamic strain alternated in tension compression cycles and fluctuated, while transverse strain merely fluctuated. With the increase of the depth and the speed, the dynamic strains decreased according to the decrease of the axle loads. The transverse strain was greater than the longitudinal value, and the amplitude of the former was more sensitive to the influence factors than that of the latter. Sensitivities of dynamic strains and their amplitude to axle load and vehicle speed decreased from top to bottom. The differences between dynamic and static strains existed different rules in three layers. The results can be applied to the structure design or material selection of asphalt pavement on steel bridge.