考虑不同配筋率影响的板柱节点抗冲切性能分析

冲切破坏是钢筋混凝土板柱结构的主要破坏形式。通过对ACI318-08、Eurocode 2、GB50010-2010等规范中关于板柱节点受冲切承载力计算公式的对比分析,发现对于板中配筋率的影响可否忽略以及影响程度等问题的考虑并不统一。为深入研究配筋率对板柱节点抗冲切性能的影响,在考虑材料和几何非线性的基础上,通过有限元软件OpenSEES对5个配筋率分别为0.5%(2个)、0.99%、2.0%及3.0%的板柱节点试件进行数值模拟和参数分析,对比分析各试件的承载力、刚度变化过程及破坏特征,发现模拟结果和试验结果吻合较好。研究表明:配筋率是进行板柱节点抗冲切设计不可忽略的影响因素,建议在规范修订中考虑此参数。最后还分析了其抗震性能及混凝土强度对抗冲切承载力的影响。

Punching Shear Capacity Analysis of a Slab-column Connection Considering the Effect of Different Reinforcement Ratios

A slab-column structure is a bearing system,which is composed of a plate and a column.Because there are no ribs,force transfer is simple,that is to say,the load passes to the foundation directly through the column.This structure has some advantages such as optimization of space and steel plate use,layout flexibility,and quick construction.To improve the punching shear capacity of the concrete slab and to reduce its span,we often set the column head on top of the column.Punching shear has been the object of intense experimental effort since the 1950s.Some codes account for size or membrane effects,or the ratio of column size to the depth of the slab.Here,comparative analysis of formulas for punching shear strength calculations following ACI318-08,Eurocode 2,and GB50010-2010 is carried out.The research shows that the effect of the reinforcement ratio is not always uniform.Using five samples with different reinforcement ratios,which is 0.5% (two),0.99%,2.0%,and 3.0%,respectively,the numerical simulation and parameter analysis is performed with Open System for Earthquake Engineering Simulation (OpenSEES) considering the material nonlinearity and geometric nonlinearity.The proposed numerical method successfully simulates the punching shear capacity of slab-column connections in terms of the load-deformation curve,stiffness variation,and failure characteristics.The research results show that the reinforcement ratio is the key factor in punching shear resistance and should be considered appropriately in any code revision.Finally,the analysis of punching shear strength is also presented with regard to concrete.