Seismic performance of CFST column bolted flange splice joints with connecting plates and rebar hooks

Abstract

A stiffened bolted flange splice joint configuration with connecting plates and rebar hooks for concrete-filled steel tubular columns is proposed for high-rise prefabricated steel structures. Four full-scale specimens with different flange thickness or different stiffener layouts were tested under cyclic loads, and the hysteretic behaviors, performance indicators, ductility and stiffness were analyzed. Compared with conventional joints, the bolted flange splice joints with connecting plates and rebar hooks show higher yield moments and stiffness. Finite element models that were verified by test results were established and adopted to further analyze the seismic performance of these proposed joints. The rotation capacity and stress distribution were analyzed, and the stiffened joints with connecting plates and rebar hooks could be regarded as rigid for high-rise structures based on the stiffness. Parametric analysis was conducted to analyze the influences of connecting plate or rebar hook parameters, proposing design recommendations accordingly. Formulas of the yield moments for these stiffened joints were proposed, and the calculated results have good agreements with that of tests and the FE analysis, indicating that the formulas could be used in the practical design.