Experimental Study on L-shaped Concrete-filled Steel Tubular Columns under Axial Compression and Eccentric Compression

Special-shaped concrete-filled steel tubular columns are widely utilized in high-rise buildings.In order to further simplify the construction steps and increase the application scope, a novel L-shaped concrete-filled steel tubular column (LCFSTC) was proposed.Nine specimens, scaled at 1:1, were designed and grouped with specimen lengths of 0.5, 1.0, and 2.0 m.Compressive tests were performed on the nine specimens under various experimental parameters, including specimen length, concrete strength, and loading conditions (axial or eccentric loading).The tests aimed to verify the reliability of the LCFSTC and explore its mechanical properties by analysing failure modes, load-vertical deflection curves, load-rotation angle curves, and load-strain curves.Results demonstrate that no specimen experienced weld seam failure, indicating good structural integrity for the LCFSTCs.For the axial-loading specimens, the bearing capacity and ductility increase with the specimen length.As the specimen length increases from 0.5 m to 1.0 and 2.0 m, the ductility coefficient (mean value) decreases by 23.0% and 47.2%, respectively.Increasing the concrete strength can improve the bearing capacity; the average bearing capacity of the specimens with a concrete strength of C40 increases by 17.1% compared with that of the C30 specimens.Eccentric loading increases the lateral deformation and affects the strain distribution and bearing capacity.This study can provide a good reference for the application and design of special-shaped concrete-filled steel tubular columns.