重复荷载下栓钉抗剪连接件的性能研究

Performance study on stud shear connectors under repeated loads

在重复荷载和单调荷载作用下进行12个栓钉抗剪连接件推出试验,对钢-混凝土组合结构中栓钉的破坏模式、屈服模式、疲劳机制、承载力、刚度退化、耗能等动力性能与静力性能进行研究,重点分析了栓钉直径、混凝土强度等参数对栓钉的疲劳性能和抗剪性能的影响。研究结果表明:栓钉抗剪连接件的破坏模式有栓钉剪断和混凝土开裂,在重复荷载下表现出疲劳现象,如承载力下降、混凝土初始裂缝的发展。单调荷载下,栓钉的直径由13mm增加为16mm时承载力提高20.55%,栓钉直径由16mm增加为19mm时极限承载力提高11.7%。混凝土强度等级从C30提高到C50,对应承载力也有一定提高,增幅为3%。重复荷载下栓钉直径由13mm增加为16mm时,承载力提高35%,初始刚度提升明显,耗能能力提高40%。混凝土强度的提高对承载力和初始刚度影响不明显,但刚度退化稳定,耗能能力提高27.5%~47.3%。整体来看,栓钉抗剪连接件表现出良好的抗疲劳能力。

Based on the push-out test of 12 stud shear connectors under repeated loads and monotonic loads,dynamic and static performances of the studs in the steel-concrete composite structure were investigated,including the failure modes,yield patterns,fatigue mechanism,bearing capacity,stiffness degradation and energy dissipation performance.And the influence of the parameters on the fatigue performance and shear resistance of the studs were analyzed such as the diameter of the stud and the strength of the concrete.The results show that the failure modes can be divided into stud shear failure and concrete crack.And the fatigue phenomenon under repeated loads occurs such as decrease of bearing capacity and the development of the initial cracks in the concrete.Under monotonic loads,the bearing capacity is increased by 20.55% when the diameter of studs is increased from 13mm to 16mm,and the ultimate bearing capacity is increased by 11.7% when the diameter of studs is increased from 16mm to 19mm.When the strength of concrete is increased from C30 to C50,the corresponding bearing capacity is also increased by 3%.When the diameter of studs is increased from 13mm to 16mm under repeated loads,the bearing capacity is increased by 35%,and the initial stiffness is increased significantly,and the energy dissipation capacity is increased by 40%.The increase of concrete strength has no obvious influence on bearing capacity and initial stiffness,but the stiffness degrades steadily and the energy dissipation capacity is increased by 27.5%~47.3%.On the whole,the stud shear connector shows good fatigue performance.