钢-UHPC组合结构新型剪力件的抗剪性能

Shear performance of innovative shear connectors in steel-UHPC composite structure

为了解决钢-UHPC组合桥面板因UHPC层较薄导致剪力件高度受限、施工难度大、抗剪强度和刚度不足等问题,提出弧形钢筋、栓钉+弧形钢筋2种新型剪力连接方式.考虑剪力件直径的影响,设计7组共14个推出试件,通过与栓钉剪力件对比分析,研究剪力件的抗剪性能及承载力.结果表明:3种剪力件的破坏形态及破坏机理、荷载−滑移曲线变化规律区别明显.弧形钢筋剪力件的延性和刚度均优于另外2种剪力件,且与直径呈线性关系.基于线性回归分析,给出考虑栓钉周围楔形块对栓钉剪力件抗剪贡献的承载力计算公式、考虑弧形钢筋和其内部UHPC共同抗剪的承载力计算经验公式,计算结果与试验值较吻合.

Two innovative shear connector named arc-shaped reinforcement and stud+arc-shaped reinforcement were proposed,in order to solve the problems of limited height of shear connector,difficult construction,insufficient shear strength and stiffness resulted by the thin UHPC layer of steel-UHPC composites bridge deck.Considering shear connector diameter,a total of fourteen push-out specimens for 7 groups were designed,the shear properties and bearing capacity of shear connectors were comparatively analyzed with studs.Experimental results show that the failure patterns and mechanisms,variation law of load-slip curve of the three kinds of shear connectors are quite different.Both the ductility and stiffness of arc-shaped reinforcement shear connectors are better than the other two kinds of shear connectors,which keep linear relation with diameter.Based on the linear regression analysis,the bearing capacity calculation formula of stud,considering the shear contribution of wedge-shaped block around studs,and empirical formula of arc-shaped reinforcement shear connectors,considering the shear strength of arc-shaped steel bar and its internal UHPC strength were given respectively,which were in good agreement with the experimental results.