Behaviour of steel-concrete-steel sandwich walls with EC connectors under out-of-plane patch loads

Abstract

This paper investigated the punching shear behavior of new steel-concrete-steel sandwich walls with enhanced C-channels (SCSSW-ECs), which is proposed as high-performance structural elements, e.g., the shear walls or protective structures. Thirteen SCSSW-ECs, designed with different faceplate thickness (ts) and spacing of ECs (S), were simply supported and tested under different square patch loading (Wa) at their geometric center. Test results showed that under patch loads SCSSW-ECs exhibited three load-deflection (P-δ) manners due to the varying S and Wa values. There were two peak resistances and four (or five) working stages in P-δ curves that include elastic (or nonlinear developing), first recession after first peak, rebounding, and final recession stages. Punching shear (PS) of concrete core (or flexure-governed mode) and PS of steel faceplate occurred at the first and second peak resistances of P-δ curves for SCSSW-ECs, respectively. Increasing the ts improved P-δ behaviours of SCSSW-ECs especially its post first peak load behaviors. Increasing the S of enhanced C-channels of SCSSW-ECs significantly reduced their peak resistances. Increasing the Wa changed the failure mode of SCSSW-ECs from PS to flexure, and improved the ductility of P-δ behaviours. Finally, the proposed analytical models reasonably estimated the punching shear resistances of SCSSW-ECs.