Design method of concrete-encased column connections for thin-walled CFST piers

Abstract

To simplify the construction process of traditional concrete-encased column connections (CECCs), an improved type of CECCs has been proposed for circular concrete filled steel tube (CFST) piers, in which anchor bars are employed to replace the end plate and anchor bolts. Preliminary experimental studies have been conducted to investigate the seismic performance of CFST piers with such connections. In this paper, design methods for CFST piers using CECCs are further investigated and proposed. The finite element model (FEM) is first developed and verified against the test results. Then, parametric studies are conducted to clarify the influence of various parameters on the mechanical performance of CFST piers with CECCs. Based on the FEM results, the design methods for the sectional strength and the load versus displacement skeleton curve model are proposed, resulting in relatively accurate and conservative prediction results.