Cyclic tests and analyses of extended endplate composite connections to CFDST columns

Abstract

ABSTRACT Many existing investigations have focused on the performance of concrete filled double skin steel tubular (CFDST) members. However, there is a lack of research on the behavior of beam to CFDST column joints. This paper presents an experimental investigation and a numerical analysis of the CFDST column to composite beam joint with extended end plates. A series of joint specimens, that were composed of composite beams and square and circular CFDST columns connected by extended end plates and blind bolts, were tested under lateral cyclic loads. In addition, analytical models for this type of connection were established by ABAQUS software. The bolt washer and nut were idealized as circular parts to solve the convergence problem induced by the complex interactions. Nonlinear springs were employed to simulate the behavior of shear studs. The predicted results from the analytical models coincided well with the test results in terms of the failure modes and hysteretic curves. Furthermore, a total of sixteen parameters were analyzed to assess their influence on the structural behavior of typical square and circular CFDST column composite connections with extended end plates. The experimental and analytical results demonstrate that the extended end plate composite connections to square and circular CFDST columns have excellent seismic performance and are applicable in high-intensity earthquake regions.