型钢剪力架增强混凝土板柱节点抗冲切试验研究

EXPERIMENTAL STUDY ON PUNCHING-SHEAR RESISTANCE OF REINFORCED CONCRETE SLAB-COLUMN JOINTS REINFORCED WITH SSF

研究型钢剪力架增强钢筋混凝土板柱节点的抗冲切性能,得到型钢剪力架设计的优化方案。考虑型钢的翼缘厚度、腹板厚度、伸臂长度、锚固栓钉规格不同,设计9个板柱节点试件进行反向静力模拟加载试验,考察试件的破坏历程和破坏形态,量测节点的承载力、变形和应变等指标,调查不同设计组合对板柱节点抗冲切破坏模式和承载力的影响规律,阐明其失效破坏机制。结果表明:型钢剪力架能够提高板柱节点的抗冲切性能,改善冲切破坏的脆性特点;设置型钢翼缘、锚固栓钉能够强化节点内纵筋、型钢和混凝土的协同工作,增加型钢腹板厚度和设置翼缘均可在一定程度上提高板柱节点的抗冲切承载力和延性能力;锚固栓钉代替型钢翼缘可改善板柱节点的抗冲切承载力,但在改善延性方面的效果不如带翼缘试件;增加翼缘厚度来提升承载力存在边际效应,型钢伸臂长度太短难以发挥型钢剪力架的抗冲切增强作用。参考现有规范方法以及试验结果,提出了型钢剪力架增强混凝土板柱节点抗冲切承载力计算方法。

This paper is to study the performance of reinforced concrete slab-column joints reinforced with section-steel shear-resistance cross frame(SSF)against punching and shearing,and to obtain an optimal solution for the design of SSF.Considering the different specifications of flange thickness,web thickness,outrigger length and anchor pins,9 test specimens of slab-column joints subjected to reverse static simulation loading were designed to investigate the damage history and mode of the specimens,to measure the bearing capacity,deformation and strain of the joints,to investigate the influence of different combinations on the damage mode and bearing capacity of the slab-column joints,and to clarify the failure damage mechanism.The results show that the SSF can improve the shear resistance of slab-column joints and inhibit the brittle characteristics of shear damage.The anchoring pins instead of steel flange can improve the punching shear load capacity of the slab-column joint,but the improvement of ductility is not obvious;increasing the thickness of the flange to improve the load capacity has a marginal effect,and the length of the steel outrigger is too short to play the punching shear strengthening effect of the SSF.With references to the existing methods and test results,the calculation method is proposed for punching shear bearing capacity of reinforced concrete slab-column joints reinforced with SSF.