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