Behavior of CFSTs and CCFSTs under quasi-static axial compression

The behavior of circular Concrete Filled Steel Tubes (CFST) and Confined Concrete Filled Steel Tubes (CCFST) with Glass Fiber-Reinforced Polymers (GFRP) wrapping sheets subject to concentric compressive quasi-static loads is investigated in this paper. Thirty five CFST and CCFST specimens were tested to investigate the effect of different parameters on their behavior. Two concrete compressive strengths of 44 MPa and 60 MPa combined with three diameter-to-thickness (D/t) ratios of 54,32, and 20 were considered. It was found that the dominant failure mode of the CCFST specimens is the explosive rupture of the GFRP wraps at the specimen's mid-height region. Even though the strain hardening region is as apparent in the CCFST specimen as its CFST benchmark, the CCFST section's axial load-carrying and ductility capacities have considerably increased due to the GFRP additional confinement. (C) 2013 Elsevier Ltd. All rights reserved.