基于大直径栓钉界面连接的钢-UHPC组合结构推出试验研究

Experimental Study of Steel-UHPC Sheet with Large Diameter Stud Interface Connection

为深入研究大直径栓钉在超高性能混凝土(ultra-high performance concrete, UHPC)和普通混凝土(normal concrete, NC)中的破坏模式及力学特征,对7组试件进行了推出试验研究,详细分析了混凝土强度、混凝土板厚、栓钉直径、栓钉长径比及混凝土试件尺寸对大直径栓钉极限抗剪承载力的影响规律。结果表明:UHPC试件破坏模式为栓钉剪断,UHPC能够有效抵抗栓钉产生的劈裂力,有效防止发生混凝土板劈裂破坏;与NC试件相比,UHPC试件的抗剪承载力和抗剪刚度更高,但延性较低;在UHPC试件中,大直径栓钉的长径比、混凝土板厚及混凝土板尺寸对栓钉抗剪承载力、抗剪刚度和极限滑移影响较小。最后,根据试验结果提出了UHPC中大直径栓钉剪断破坏模式下的荷载-滑移曲线及抗剪承载力计算建议公式,可为钢-UHPC组合结构工程设计提供一定的参考。

In order to further study the failure mode and mechanical characteristics of large diameter stud in ultra-high performance concrete(UHPC)and normal concrete(NC),the push-out tests of 7 groups of specimens were carried out.The influences of concrete strength,slab thickness,stud diameter,stud length-diameter ratio and concrete specimen size on the ultimate shear capacity of large diameter stud were analyzed in detail.The results showed that the failure mode of large diameter stud UHPC was stud shear.UHPC could effectively resist the splitting force generated by the stud and prevent the splitting failure of concrete slabs effectively.Compared with NC specimens,UHPC specimens had higher shear capacity and shear stiffness,but lower ductility.In UHPC specimens,the length-diameter ratio of large diameter stud,the thickness of concrete slab and the size of concrete slab had little influence on the shear capacity,shear stiffness and ultimate slip of the stud.Finally,according to the test results,the proposed formula for calculating load-slip curve and shear capacity of UHPC large diameter stud under shear failure mode were proposed,which could provide certain reference value for the engineering design of steel-UHPC composite structure.