Shear behavior of high-strength square concrete filled steel tube members

Abstract

This paper experimentally and numerically investigates the shear behavior of high-strength square concrete-filled steel tube (HS-SCFST) members. A total of 20 specimens were first tested. The test parameters were the shear span-to-depth ratio, width-to-thickness ratio of the steel tube wall, yield stress of steel, and compressive strength of concrete. Detailed finite element (FE) models were then developed and benchmarked. The benchmarked models were then used to conduct a total of 87 parametric studies. It was shown that (i) the shear strength and stiffness increased with decreasing shear span-to-depth ratio or width-to-thickness ratio, and (ii) the increase in yield stress of steel and compressive strength of concrete improved the shear strength, but had a minor effect on the stiffness. Results from the experimental tests and finite element analyses were also used to evaluate the applicability of several international design provisions (e.g., AASHTO BDS, Eurocode 4, WSDOT BDM and CECS 28) for estimating the shear strength of HS-SCFST members. It was shown that CECS 28 provided the most reasonable estimation of the shear strength, but the contribution of steel tube and concrete infill was not accurately calculated. A new design equation was therefore proposed, considering the effect of shear span-to-depth ratio and the contribution of the steel tube and concrete infill. • Investigates the shear behavior of high-strength CFST members. • Conducts experimental tests and FEM analysis. • Discusses the shear transfer mechanism. • Evaluates the applicability of several international design provisions. • Proposes a design equation considering the effect of shear span-to-depth ratio.