薄层沥青混凝土在桥面铺装中的力学响应

采用ABAQUS有限元分析软件, 建立水泥混凝土箱梁桥与工字梁桥三维整体有限元模型, 分别研究了不同厚度薄层沥青混凝土铺装层在车辆荷载和温度荷载作用下的力学响应, 以及铺装层自重对桥梁结构内力的影响。研究结果表明: 在车辆荷载作用下, 铺装层厚度由4 cm增加至12 cm时, 箱梁桥与工字梁桥铺装层最大竖向剪应力分别增长了约72%与40%, 因此, 薄层铺装能够降低层内竖向剪应力水平, 有利于缓解车辙病害的发展; 在温度荷载作用下, 铺装层厚度对层内拉应力及层底剪应力的影响并不明显, 力学指标基本处于同一水平; 在重力荷载作用下, 厚度为4 cm的薄层铺装相对于12 cm的铺装层能够分别降低箱梁桥桥体内部最大Mises应力及最大主拉应力19.62%与17.70%, 而对于工字梁桥而言, 能够分别降低应力水平13.79%与10.16%, 从而改善了桥梁结构受力状况。可见, 薄层沥青混凝土应用于桥面铺装具有良好的力学可行性, 在综合考虑环境与材料性能的基础上可在实际工程中推广应用。

Mechanical responses of thin-layer asphalt concrete utilized in bridge deck pavement

Thin-layer asphalt concrete was paved on cement concrete bridge, finite element analysis software ABAQUS was utilized to build the 3D models of box girder bridge and flanged girder bridge respectively, and the mechanical responses of pavementes with different thicknesses under traffic and thermal loads were analyzed.In addition, the effect of pavement gravity on bridge structure was studied.The result indicates that the maximum vertical shear stresses in box girder bridge and flanged girder bridge increase by about 72% and 40% respectively under vehicle load when pavement thickness increases from 4 cm to 12 cm.Thus, the possibility of the rutting occurrence decreases because of the application of thin-layer pavement.The influence of pavement thickness on the tensile stress is not obvious under thermal load, and each mechanical index is at the similar level.Under the gravity of pavement, the maximum Mises stress and principle tensile stress in box girder bridge respectively decrease by 19.62% and 17.70% by decreasing pavement thickness from 12 cm to 4 cm.At the same condition, the stress levels in flanged girder bridge respectively decrease by 13.79% and 10.16%, and the stress distribution in bridge structure is meliorated.Therefore, thin-layer asphalt concrete is feasible to be utilized in bridge deck pavement when environment condition and material performance are considered in actual engineering.