Hysteretic behavior of multi-cell L-shaped concrete-filled steel tubular columns at different loading angles

Abstract

Multi-cell L-shaped concrete-filled steel tubular (CFST) columns have the advantages of avoiding column protrusion, saving room space and good mechanical behavior. They can be used as the corner columns in building structures. In practical engineering, the columns may be subjected to earthquake action from different directions. However, there are few experimental and numerical studies on this kind of columns at different loading angles. This paper presents four tests carried out on multi-cell L-shaped CFST columns subjected to combined constant compression and lateral cyclic loads. The main variables were loading angles (0°, 45° and 135°) and axial load levels (0.25 and 0.5). The failure modes, lateral load – displacement hysteretic curves, envelope curves, stiffness degradation, ductility, energy dissipation, deformation and moment – curvature curves were obtained. A finite element model was developed to simulate the multi-cell L-shaped CFST columns at different loading angles, and the predicted results agreed well with the test results. Moreover, the parametric analysis was conducted to investigate the effects of various parameters on lateral load – displacement curves of the columns under diagonal loading.