Failure mechanism and failure patterns of SCS composite beams with steel-fiber-reinforced UHPC

Abstract

Steel–concrete–steel (SCS) composite structures are widely applied in nuclear power plants, tunnels, and offshores. In this study, steel-fiber-reinforced ultra-high performance concrete (UHPC) is adopted as a core material to improve the structural behaviors of SCS composite structures. A series of static tests on SCS composite beams with UHPC under shear loads are performed to analyze failure patterns and failure mechanism. Results indicate that match relation between steel plates and core UHPC has an important effect on the structural behavior of SCS composite beams with UHPC; furthermore, effects of cross ties on the composite action between steel plates and core materials cannot be neglected. In addition, three-dimensional finite element (FE) models for SCS composite beams with UHPC are established and verified to investigate the effects of match relation between steel plates and core UHPC on the failure mechanism. Based on the experimental and FE simulation results, contribution coefficients of steel plates are proposed to reflect the composite action between steel plates and core materials for SCS composite beams with UHPC. Moreover, the judgment method of failure patterns for SCS composite beams with UHPC is studied. Finally, analytical method to predict the ultimate resistance for SCS composite beams with UHPC is presented and validated by comparison with ACI 349-06 and JEAG 4816 codes.