Parametric Study on Cyclic Behavior of Hexagonal Concrete-Filled Steel Tubular Columns

The seismic performance of columns plays a decisive role in the safety of steel–concrete composite structures. Although the seismic behavior of concrete-filled steel tubular (CFST) columns has been extensively investigated. However, the cyclic behavior of hexagonal concrete-filled steel tubular (HCFST) columns equipped with continuously distributed Perfobond Rib (PBL) shear connectors along the column has not yet been comprehensively studied. To this end, a cyclic loading test was first conducted on an HCFST specimen with continuously distributed PBL shear connectors. Subsequently, a three-dimensional finite element model was developed in ABAQUS and validated against the experimental results in terms of hysteretic response, local damage, and failure mode. The results showed that the use of PBL shear connectors increased the lateral load-carrying capacity and lateral displacement capacity by approximately ۶% and ۱۵%, respectively; compared with the specimen containing half the number of shear connectors, and by approximately ۱۴% and ۲۵%, respectively, compared with the specimen without PBL shear connectors. In addition, increasing the concrete compressive strength from ۳۰ MPa to ۵۰ MPa enhanced the lateral load capacity by ۲۱–۲۷%, although this improvement gradually diminished with increasing column slenderness. Furthermore, reducing the D/t ratio from ۷۵ to ۶۶.۷ increased the lateral load-carrying capacity by approximately ۱۸–۳۳%, whereas increasing the column height adversely affected the seismic performance. In all cases, the dominant failure mode was characterized by local buckling of the steel tube and damage concentrated at the column base. The findings of this study provide not only a validated numerical model but also valuable design information for the seismic assessment and design of HCFST columns equipped with PBL shear connectors.

کلیدواژه ها:

Hexagonal Concrete ، Steel Tubular Column ، Parametric study ، lateral stiffness ، Numerical modeling ، Cyclic behavior