Seismic behavior of wide-limb special-shaped columns composed of concrete-filled steel tubes

Abstract

To study the seismic performance of wide-limb L-shaped columns composed of concrete-filled steel tubes (W-LCFST columns), five specimens were fabricated and tested under quasi-static cyclic loading. The W-LCFST column was composed of a center mono column, two side mono columns, and vertical connecting steel plates. The mono column was made of steel tube and an infill of concrete. The cavity between the vertical connecting plates was also filled with concrete. The test focused on the parameters including vertical connecting plates with headed studs or perfobond leiste (PBL) stiffeners inside and the sectional dimension of the side mono column. The ultimate failure mode, force-displacement curves, ductility, strength degradation, stiffness degradation, energy dissipation capacity, and strain distribution under different influence factors were discussed. The results showed that all specimens exhibited buckling and fracture failure at the bottom of the W-LCFST column. Increasing the width of the side mono column can increase the initial stiffness. Compared with the headed studs, the PBL stiffeners had a better effect on preventing large-area buckling of the vertical connecting plates and improving the peak bearing capacity and stiffness. Based on the limit state theory, the calculation method of the sectional flexural capacity of the W-LCFST column was established. Additionally, the accuracy of predicting the compression and bending capacity of the W-LCFST column under positive and negative loads by Standard CECS159–2004 was analyzed, and the recommended correction value was also given.