基于轨道极限状态法的过渡板受力分析和配筋设计研究

京张高铁官厅水库特大桥为简支拱型大跨度钢桁梁桥,为防止梁端转角或错台量过大,降低梁端扣件系统受力,梁缝处设计采用了过渡板结构。为保证过渡板设计合理性和安全性,建立过渡板有限元实体模型进行受力分析,并首次运用轨道极限状态法对过渡板结构进行配筋设计。分析表明:(1)温度梯度作用对过渡板(420 mm厚)受力影响较大,在设计荷载中占据主导因素,在正温度梯度下,过渡板底部弯矩达到124.155 kN·m/m;(2)过渡板底部纵向弯矩在荷载基本组合作用下达到最大值,且实配配筋率最大,配筋时应注意以裂缝宽度为控制指标进行设计。

Research on Force Analysis and Reinforcement Design of Transition Slab Based on Limit State Design Method of Railway Track

The Guanting Reservoir Super Major Bridge of Beijing-Zhangjiakou High-speed Railway is a long span simply-supported steel truss bridge. To prevent excessive rotation angle or faulting at the bridge end and reduce stress of fasteners at the bridge end, the bridge gap design uses transition slab structure. To ensure the reasonability and safety of the transition slab, this paper builds a finite element solid model to analyze the stress of the slab and uses Limit State Design Method of railway track in the first time in the reinforcement design. The analysis shows:(1)Temperature gradient has a great impact on the transition slab(420 mm thickness) stress and plays a dominant role in the design load; under the action of positive temperature gradient, the bending moment at the bottom of transition slab is up to 124.155 kN·m/m.(2)The longitudinal bending moment at the bottom of the transition slab is maximized under basic combination loads, and actual reinforcement ratio is the largest. The reinforcement should be designed with crack width as a control index.