高强度螺栓咬合型连接的受拉试验研究

Experimental study on tensile behaviour of occlusive high strength bolt connections

为研究支吊架用高强度螺栓咬合型连接的破坏机理与受拉承载力,分别进行了单个螺栓咬合型连接和典型连接的抗拉试验及有限元分析。考虑了槽钢和高强度螺栓规格等参数的影响,单个螺栓抗拉试验中共有66个试件,由六家企业提供。试验结果表明,在螺栓拉力作用下槽钢两侧卷边均绕腹板顶部棱线转动,并形成两条塑性铰线;螺栓安装扭矩对受拉承载力无影响。采用门式支架进行典型连接抗拉试验,按槽钢壁厚不同共设计6个试件。通过试验研究发现,角钢连接件对螺栓产生明显的撬力。为研究单个螺栓连接中槽钢塑性铰线长度和典型连接受拉承载力随固定螺栓间距和槽钢规格的变化情况,又对4个试件补充了有限元分析。结果表明:塑性铰线长度仅与槽钢卷边尺寸有关;角钢连接件的撬力作用能够约束卷边的竖向位移,提高卷边屈服荷载。根据试验和有限元分析结果,给出了单个螺栓连接受拉承载力设计值的计算方法,理论计算值与试验结果吻合较好。

In order to study the failure mechanism and tensile capacity of occlusive high strength bolt connections for supports and hangers, tensile tests and finite element analysis of single bolt and typical connections were carried out separately. By considering the influence of channel parameters and high strength bolt specifications, a total of 66 specimens provided by six companies were tested under the single bolt tensile test. The test results show that rolled edges on both sides of the channel rotate around top edge lines of webs under the bolt tension force, and form two plastic hinge lines. The bolt installation torque does not affect the tensile capacity. The typical connection tensile test adopted portal support, with a total of six specimens, and the wall thickness of the channel was varied. It is found that the angle connector has obvious prying force to the high strength bolts. In order to study influence of spacing of fixed bolts and the specification of the channel steel on the length of the plastic hinge line of the channel in single bolt connection and the tensile capacity of typical connection, the finite element analysis was supplemented for four specimens. Analysis shows that the length of the plastic hinge line is only related to the size of rolled edges. The prying force of the angle connector can restrain the vertical displacement of rolled edges and increase the yield load. According to test results and finite element analysis results, the calculation method of the tensile capacity of single bolt connection is given, the calculated values are in good agreement with the experimental results.