An Experimental Study on the Performance of L-Shaped CFSTs Connected by Double-Corrugated Steel Plates Under Axial Compression

Special-shaped, concrete-filled steel tubes (SCFSTs) enhance the space efficiency of residential structures and improve aesthetics by avoiding exposed columns. However, the flat steel-plate connection sections are susceptible to local buckling. To mitigate this, corrugated steel plates are incorporated to enhance the local buckling resistance of the structure. This study examines the axial-compression performance and damage characteristics of SCFSTs connected by double-corrugated steel plates (DCP-SCFST) through full-scale static-loading tests. A finite element analysis explores the impact of column height, corrugated plate thickness, material strength, and connection length on the load-carrying capacity of DCP-SCFSTs. The study also presents the sectional strength and design method for these structures. The results indicate that the DCP-SCFSTs exhibit high bearing capacity and ductility under axial compression. The corrugated plates effectively restrain the concrete, markedly improving the buckling behavior of the connection section. Moreover, the corrugation wave size does not significantly affect the bearing capacity, whereas increasing the corrugated plate’s thickness enhances both the bearing capacity and ductility. This is attributed to the indirect confinement effect of corrugated plates. Additionally, the paper proposes design methods for sectional strength and overall stability, offering accurate formulas that offer valuable reference for the design of concrete-filled, corrugated plate members.