带约束构造的栓钉剪力连接件承载力研究

Research on bearing capacity of stud shear connector with constraint measure

为解决栓钉剪力连接件“剪撬”局压劈裂的问题,提出一类带约束构造的栓钉剪力连接件,通过推出试验研究了该新型栓钉连接件在钢-混凝土板之间的界面抗剪受力性能。试验研究表明:对传统栓钉进行约束构造改良后,可将混凝土劈裂裂缝控制在约束范围,有效地抑制混凝土局部劈裂扩展贯通,减小界面抗剪刚度随时间不断降低的不利影响;约束构造提高了栓钉在混凝土板内传力效率,优化了栓钉剪切传力机理,改变了依赖横向钢筋来抵抗栓钉纵向抗剪作用的方式;较大直径栓钉(22mm、25mm)借助约束构造可使混凝土翼缘板发生整体压溃破坏,从而能充分发挥大直径栓钉的承载优势及混凝土翼缘板的承载能力。基于对带约束构造的栓钉剪力连接件的界面剪切传力机理及破坏模式分析研究,提出了适用于该新型剪力连接件承载力计算公式及分别对应混凝土板整体压溃破坏、栓钉剪断破坏两种破坏方式的初步判别方法,且文中建议的带约束构造的新型栓钉剪力连接件破坏准则能较好地吻合试验结果及破坏现象。

In order to solve the problem of local pressure splitting of stud shear connector "shear pry", a kind of stud shear connector with constraint measure is proposed. The shear performance of the interface between steel-concrete plate of the new stud connector is studied through push out test. The experimental results show that after the improvement of the constraint measure of the traditional stud, the concrete splitting crack can be controlled within the constraint range.The local splitting propagation and penetration of the concrete can be effectively constrained, and the adverse effect of the decreasing interface shear stiffness with time can be reduced. The constraint measure improves the force transfer efficiency of the stud in the concrete slab, optimizes the shear force transfer mechanism of the stud, and changes the way of relying on the transverse reinforcement to resist the longitudinal shear action of the stud. With the help of constraint measure, the larger diameter stud(such as 22mm, 25mm) can cause the overall crushing failure of the concrete flange plate, so as to give full play to the bearing advantages of the larger diameter stud and the bearing capacity of the concrete flange plate. Based on the analysis and research on the interface shear force transmission mechanism and failure mode of the stud shear connector with constrained measure, the calculation formula of bearing capacity suitable for the constrained measure and the preliminary judgment methods of the two failure modes corresponding to the overall failure of concrete slab and the shear failure of stud were proposed. The proposed failure criterion of the new stud shear connector with constrained measure is in good agreement with the experimental results and failure phenomenon.