Experimental investigation on the behavior of the steel–concrete composite frames with uplift-restricted and slip-permitted screw-type (URSP-S) connectors

Abstract

The uplift-restricted and slip-permitted screw-type (URSP-S) connector is proved be very useful to improve the crack resistance of the concrete decks in the negative bending moment areas in steel–concrete composite bridges, thus it has been widely used recently in China. However, its application in building structures is very limited. In this paper, the structural behavior of steel–concrete composite frames with URSP-S connectors was experimentally investigated. A total of three composite frame specimens with different connector types and arrangements of the interface of composite beams were designed and tested. The load–deflection curves, hysteresis behavior, slab crack, strain, and interface slip under vertical and lateral cyclic loading cases were analyzed. The results indicated that compared with full-span stud connectors, after applying URSP-S connectors, the crack number and width of the concrete slab was effectively reduced, as well as the tensile strain of the concrete and rebar of the slab, while the interface slip of composite frame beam was notably enhanced, the stiffness of the composite frame with URSP-S connectors became slightly lower under vertical and lateral loading cases. Moreover, the composite frame with URSP-S connectors exhibited good seismic behavior under lateral cyclic loads, and the use of URSP-S connectors rarely affected the bearing capacity of the structures.