单面自紧螺栓成型机理与受剪承载力试验研究

Forming mechanism and experimental study on shear capacity of one-side self-tightening bolt

针对传统扭剪型高强螺栓连接施工过程中往往需要两个操作面,难以应用于闭口截面构件之间连接的问题,设计开发一种单面自紧高强螺栓(self-tightening high strength one-side bolt, SHSOB)。通过对SHSOB螺栓的试验研究,考察了其成型机理、安装工艺和受力性能,获取了SHSOB螺栓的破坏模式、预紧力时变效应、抗滑移系数及剪力-位移曲线。研究表明:SHSOB螺栓预紧力可以满足GB 50017—2017《钢结构设计标准》中高强螺栓预紧力的设计要求;预紧力松弛在起始阶段较快,随后趋于稳定;SHSOB螺栓连接的受剪破坏模式和剪力随时间的变化规律均与传统扭剪型高强螺栓相似,均以螺杆被剪断发生破坏;在发生摩擦滑移破坏前,螺栓连接的剪力由摩擦力传递,孔壁承压阶段通过螺栓杆和孔壁的压力传递。在此基础上,推导了SHSOB螺栓的受剪承载力理论计算式,对比发现理论值、试验值和规范值吻合较好,SHSOB螺栓的受剪承载力可以满足GB 50017—2017《钢结构设计标准》中摩擦型高强螺栓受剪承载力的设计要求。

In view of the fact that the traditional torsion-shear high strength bolt often needs two operating planes in the construction process and is difficult to be used to the connection between closed sections, a novel type of self-tightening high strength one-side bolt(SHSOB) was designed. The forming mechanism, installation technology and mechanical properties of SHSOBs were investigated based on experimental study. Meanwhile, the failure mode, the variation of pre-tightening force with time, the anti-slip coefficient and the shear-displacement curve of SHSOBs were obtained. The results show that the pre-tightening force of SHSOBs can meet the requirement of high-strength bolts in GB 50017—2017 ‘Standard for design of steel structures’, and the pre-tightening force relaxes quickly in the initial stage and then tends to be stable. The shear failure modes and shear-time variation of connections by SHSOBs are similar to those of torsion-shear high-strength bolts, which were destroyed by the shear of bolt rods. The shear force of SHSOB connections is transmitted through friction before the failure of friction slip, and then partly through the pressure between bolt and hole wall. Finally, the theoretical calculation formula of shear capacity of SHSOB was deduced, which has good applicability compared with the experimental and normative values. The shear capacity of SHSOB can meet the requirements of frictional high strength bolts in GB 50017—2017.