钢-预制UHPC组合梁中高强螺栓剪力键群的抗剪性能试验研究

Experimental Study on Shear Behavior of High Strength Grouped Bolted Shear Connectors in Demountable Steel-Prefabricated UHPC Composite Beams

为研究高强螺栓作为钢-预制UHPC组合梁剪力键的抗剪性能,共设计15个推出试件,探究螺栓间距和螺栓数量对试件的破坏模式、荷载-滑移曲线、极限承载力、延性和初始抗剪刚度的影响。试验结果表明,推出试件的主要破坏模式为螺栓剪力键剪断,同时在螺栓剪切面下端有局部UHPC受压剥落,UHPC预制板只在剪力槽四周出现细微裂缝。减小螺栓间距会导致试件的抗剪性能降低;而增加螺栓数量可以有效地提高试件的抗剪性能,但也会导致单栓初始抗剪刚度下降。分析国内外现行钢-混凝土组合梁中剪力键的抗剪承载力计算公式,并以此提出一条更适用于钢-预制UHPC组合梁中高强螺栓剪力键群的抗剪承载力计算公式。对比提出公式的计算值与试验值,两者的平均比值、标准差和变异系数分别为1.02、0.02和0.02。

To study the shear performance of high strength bolts as shear connectors of steel-prefabricated UHPC composite beams,a total of 15 push-out specimens have been designed to investigate the effects of bolt spacing and bolt number on failure mode,load-slip curve,ultimate shear capacity,ductility and initial shear stiffness of the specimens.The test results have shown that the main failure mode of the specimen is shear of the bolted shear connector,and the local UHPC is spalled at the lower end of the bolt shear plane.The prefabricated plate of UHPC only shows slight cracks around the shear groove.Reducing the bolt spacing will lead to a decrease in the shear performance of the specimen.Increasing the number of bolts can effectively improve the shear performance of the specimen,but it can also lead to a decrease in the initial shear stiffness of a single bolt.The current formulas for calculating the shear capacity of shear connector in steel-concrete composite beams have been analyzed,and a more suitable formula for calculating the shear capacity of high-strength grouped bolted shear connectors in steel-prefabricated UHPC composite beams has been proposed.Comparing the calculated values of the proposed formula with the experimental values,the average ratio,standard deviation and coefficient of variation of the two are 1.02,0.02 and 0.02 respectively.