基于极限状态法的轨枕板式轨道结构配筋设计研究

Research on Reinforcement Design of Sleeper Slab Track Structure Based on Limit State Method

以新建广州南沙港铁路大跨度钢桁梁桥上采用的一种新型轨枕板式轨道结构为工程背景,建立大跨度钢桁梁上轨枕板式轨道结构的分析模型,采用极限状态法对轨枕板进行配筋设计和检算;同时考虑横向预应力筋的影响,对轨枕板预应力筋的预应力损失、混凝土和钢筋应力等进行检算。结果表明:轨枕板式轨道结构在桥梁挠曲变形荷载作用下的弯矩很小,对大跨度桥梁的适应性强;轨枕板纵向下层布设20ф12钢筋,上层布设15ф12钢筋,横向上、下层各设置6ф18钢筋,横向设置12ф7预应力筋,轨枕板承载能力、裂缝宽度、钢筋和混凝土应力等均满足要求。

A new type of sleeper slab track structure was adopted on the large-span steel truss girder bridge of newly-built Nansha Port Railway in Guangzhou.Based on this engineering background,the analysis model of the sleeper slab track structure on the long-span steel truss girder bridge was established,and the reinforcement design and checking calculation of the sleeper slab were carried out by using the limit state method.At the same time,considering the influence of transverse prestressed reinforcement,the prestress loss of prestressed reinforcement of sleeper slab,the stress of concrete and reinforcement were checked.The results show that the bending moment of the sleeper slab track structure is very small under the action of bridge deflection load,and it has strong adaptability to long-span bridges.The longitudinal lower layer of sleeper slab is laid with 20ϕ12 steel bars,the upper layer is laid with 15ϕ12 steel bars,6ϕ18 steel bars are for the transverse upper and lower layers,and 12ϕ7 prestressed reinforcement are laid in transverse direction.The bearing capacity of sleeper slab,crack width,and the stress of steel bar and concrete all meet the requirements.