铁路站台单柱雨棚结构抗连续倒塌性能分析

Progressive collapse capacity analysis of platform canopies with single-column

采用非线性动力拆除构件法,对铁路站台有柱雨棚"Y"形钢筋混凝土典型单元进行了抗连续倒塌性能分析,研究了结构的连续倒塌抗力机制和失效模式;并对不同柱距、不同抗震设防烈度及不同楼板的雨棚结构进行了分析和对比。局部构件失效后,剩余结构抗倒塌机制主要为梁机制和悬链线机制;在边柱失效后,剩余结构承载机制仅有梁机制,结构抗连续倒塌性能较弱;在中柱和内柱失效的情况下,剩余结构具备梁机制和悬链线机制提供的抗倒塌承载力,结构抗连续倒塌性能较强;柱距增加,雨棚结构抗连续倒塌性能减弱;抗震设计对于结构梁机制相对承载力的提升较大,对悬链机制相对承载力的提升取决于梁内通长钢筋的增幅;整体现浇楼板对雨棚结构抗连续倒塌性能的增强效果显著,梁机制和悬链线机制的相对承载力均有较大提高。

In order to investigate the resistance mechanism and failure model of a typical column "Y"shaped reinforced concrete canopy structure,nonlinear dynamic analyses from the alternative path method are carried out in three cases. Six model canopy structures are designed and numerically analyzed to evaluate the effects of distance between columns,seismic fortification level and slab type. Research conclusions: The results show that the residual structure has two main resistance mechanism which are the beam action and the catenary action. In the case of side column removal,only the beam action works and the capacity of residual structure is extremely low. In the other two cases,both the beam action and the catenary action can work and the residual structures play a better performance on the progressive collapse capacity. The progressive collapse capacity can be improved by decreasing the distance between columns. The progressive collapse capacity of canopy structure under the beam action is significantly enhanced by higher seismic fortification level,however for the capacity under the catenary action,the enhancement extent relates to the incremental quantity of steel along the axis of beam. The progressive collapse performance of canopy structure can be improved vastly by integrated cast-in-situ slab while the capacities of the beam action and the catenary action can both be enhanced.