Investigation on interfacial anti-sliding behavior of high strength steel-UHPC composite beams

Abstract

This paper investigates the anti-sliding behavior of high-strength steel (HSS)-to-ultra-high performance concrete (UHPC) composite beams with perfobond strip connectors (PBLs). The experimental program is comprised of two test series. The first series of push-out tests were performed on six PBLs fabricated using HSS and UHPC. For each PBL, the load-slip curve, load-uplift displacement relationship, strain history, shear stiffness, ultimate resistance, failure modes, and ductility were recorded and discussed. For the second series, three HSS-UHPC composite beams were designed and manufactured. Based on the structural responses of the composite beams under four-point flexural loadings, the interfacial sliding behavior was presented and analyzed. By employing the theory of beams-on-elastic-foundation, expressions for calculating the anti-sliding stiffness of the composite beams were deduced. Experimental results indicate that the uneven load distribution among the multiple PBLs significantly reduced the shear performance of an individual PBL. Compared to a single-hole PBL, providing double holes in the perforated plate reduced the stiffness and strength of the individual PBL by 43% and 18%, respectively, while the corresponding stiffness and strength reductions for the PBL with triple holes were 51% and 19%, respectively. The perforated plates’ end-bearing effect improved the anti-sliding stiffness of the composite beam; however, the early cracking of the UHPC slab caused by the end-bearing led to a reduced yield load of the steel beam. The anti-sliding stiffness calculated from the proposed analytical formulas correlated well with experimental results. The proposed method is anticipated to provide a reference for the anti-sliding design of HSS-UHPC composite beams in practical applications.