铁路钢桥环氧沥青柔性保护层在特种活载作用下的力学响应

Mechanical response of a flexible layer on railway steel bridges under special live load

随着铁路钢桥跨径的增大,铁路采用柔性保护层的研究受到重视。从铁路钢桥桥面系的结构组成及荷载传递特点出发,建立高速列车-轨道-环氧沥青柔性保护层-桥梁耦合体系有限元模型。通过典型铁路钢桥面系算例分析可见,保护层竖向位移、横向拉应力、纵向拉应力及钢板与保护层间剪应力峰值均出现在ZK特种活载中心作用于距横隔板1/4跨处(定义两横隔板之间距离为一跨);最大竖向位移发生在荷载作用的中心区域;最大横向拉应力出现在轨枕两侧以及纵肋上方对应的区域;钢板和保护层间最大纵向剪应力分布在荷载下方轨枕对应的保护层区域。此外,通过室内试验,验证环氧沥青柔性防水保护体系的抗拉和抗剪切强度满足理论分析结果和规范的要求。列车荷载作用下环氧沥青柔性防水保护层的力学响应及其分布规律,可为同类铁路钢桥桥面系保护层设计提供理论依据。

With increase in railway steel bridge span,study on a flexible layer to be used in railway is attached importance to.A high speed train-rail-epoxy asphalt flexible layer-bridge coupled system finite element model was established based on structure composition of railway steel bridge deck and load transfer characteristics.The results of numerical examples showed that the peak values of the vertical displacement,transversal tension stress,longitudinal tension stress of the flexible layer and the shear stress between the steel deck and the flexible layer appear when the center of ZK special live load moves to the quarter of the length between two adjacent diaphragm plates;the maximum vertical displacement appears at the central region of loading,the maximum transversal tension stress appears at the corresponding region of sides of sleepers and above longitudinal ribs,and the maximum longitudinal shear stress between the steel deck and the flexible layer appears at the layer region corresponding to sleepers under the live load.In addition,the tensile strength and shear strength of the epoxy asphalt flexible layer system could satisfy the demands of theoretical analysis and specification through laboratory tests.The results of the mechanical response of the epoxy asphalt flexible layer and its distribution law under train load could provide a theoretical basis for design of protective layers on similar rail steel bridges.