十字带侧板型抗剪连接件受剪性能试验研究

Experimental study on shear performance of cross-bilinear-type shear connectors

提出一种十字带侧板型抗剪连接件,以混凝土强度、抗剪连接件长度、抗剪连接件数量为参数设计四个试件,并进行往复加载试验,研究其破坏形态、剪力-位移曲线、骨架曲线、初始刚度、抗剪承载力和应变等指标。结果表明:四个试件的破坏形态基本一致,均由抗剪连接件与混凝土梁连接处率先产生裂缝,并向上端和下端发展,在混凝土出现压溃后达到极限状态;剪力-滑移曲线走势基本相同,均包括初始弹性阶段、弹塑性阶段和破坏阶段。另外,提高混凝土强度可增大试件初始刚度达16.44%,并能有效降低位移及应变;增大抗剪连接件长度仅提高试件初始刚度的4.25%,且对位移和应变的影响也较小;提高抗剪连接件数量可使初始刚度增大47.82%,抗剪连接件始终处于弹性,且有效减小位移和混凝土损伤,以及提高试件承载能力,满足弯剪分离式组合连接节点预期1mm最大位移的要求。

In order to investigate the shear performance of an innovative cross-bilinear-type(CBT)shear connectors,four specimens with the effect of concrete strength,shear connector length and numbers were designed and analyzed by cyclic loading test,so the failure modes,shear force-displacement curves,bond curves,initial stiffness,shear capacity and shear force-strain curves of specimens were observed and obtained. The test results show that the failure modes of the four CBT specimens are nearly the same,and the cracks were caused by the cyclic load between the shear connector and the concrete beam,developed to the upper and lower ends,and reached the ultimate state after the concrete partially crushed. The trend of shear-slip curves is nearly the same,including initial elastic stage,elastic plastic stage,and failure stage. In addition,increasing the concrete strength can increase the initial stiffness by 16.44%,and it can effectively reduce the displacement and strain. Increasing the length of the shear connector only increases the initial stiffness of the specimen by 4.25%,which has little effect on the displacement and strain. Moreover,the initial stiffness of specimen will be greatly improved by 47.82% with the increase of shear strength number,and the shear connectors are always elastic,which can effectively reduce the displacement and strain,improve the bearing capacity,and meet the requirement of 1mm in the beam-to-shear link joint with bending moment and shear force separate method.