钢-超高性能混凝土组合板冲切性能试验研究和承载力计算

Experimental research on punching shear behavior and calculation of bearing capacity of steel-UHPC composite slabs

钢-超高性能混凝土(UHPC)组合板是将钢板与UHPC通过连接件组合成整体,具有高强、高延性、抗开裂、施工便利等特性,可应用于桥面板、防护工程等结构中。由于钢-UHPC组合板相对较薄且往往承受集中荷载,因此需要对其抗冲切性能进行重点研究。通过变化连接件参数、UHPC厚度、钢板厚度和加载区边长,完成了14块板件在集中荷载作用下的冲切试验。研究结果表明,配筋能显著提升组合板的承载力和延性,钢板和钢纤维使板件达到极限荷载后具有一定延性,组合板承载力随栓钉连接程度、UHPC厚度、钢板厚度和加载区边长的增大而增大。通过塑性极限理论分析了钢-UHPC组合板在弯曲机制和冲切机制下的两种承载力计算方法,并在此基础上提出了考虑折减UHPC抗冲切贡献的承载力计算方法,计算结果与试验值吻合良好。

The steel and ultra-high-performance concrete(UHPC) composite slabs have characteristics of high strength, high ductility, anti-cracking ability and construction convenience when assembled by shear connectors. It can give superiority into full play when applied in bridge deck systems and protective structures. The research on punching shear behavior of steel-UHPC composite slabs is needed because this kind of slab is thin and often bears concentrated forces. 14 slabs under punching forces with different parameters of studs, thickness of UHPC, thickness of steel plate and length of loading zone were tested. The results indicate that reinforcing bars could improve bearing capacity and ductility significantly. The steel plate and steel fiber improve the ductility of composite slabs after reaching peak load. The bearing capacity is positive correlation of connection degree, thickness of UHPC, thickness of steel plate and length of loading zone. Based on plastic limit analysis of bending model and punching model, a method considering reduction coefficient to estimate the punching bearing capacity of steel-UHPC composite slabs was proposed. The calculation results agree well with test results.