Abstract
The axial compressive performance of novel L-shaped and T-shaped concrete-filled square steel tube (L/T-CFSST) column was assessed in this study. Ten L/T-CFSST columns were tested to failure under axial load. The experimental data were used to determine various failure modes, bearing capacities, and load-displacement curves. The test parameters included the section form, steel tube thickness, steel yield strength, and slenderness ratio. The axial compressive performance of the L/T-CFSST column proved favorable, and each square steel tube showed strong cooperative performance. The failure mode of the stub column specimen (H/D ≤ 3) was strength failure caused by local buckling of the steel tube and that of the medium-long column member (H/D > 3) was instability failure caused by overall bending of the specimen. A finite element analysis (FEA) model was established and successfully validated by comparison against the test results. Based on the FEA model, parametric analyses were conducted to investigate the effects of steel tube thickness, concrete strength, steel yield strength, and slenderness ratio. The ultimate loads obtained from the experiments and FEA were compared to the results calculated by the available design codes. A formula was established to calculate the axial compressive strength and stability bearing capacity of the L/T-CFSST column accordingly. The calculation results are in close agreement with the FEA and experimental results, and the proposed formula may provide a workable reference for practicing engineers.
Highlights
Steel and concrete composite structures are widely used in civil engineering projects as they make full use of the superior material properties of steel and concrete [1]. e concretefilled steel tube (CFST) column has high bearing capacity, high ductility, strong fire resistance, and good seismic performance; formwork is not needed, so CFSTbased structures can be fabricated swiftly at relatively low cost [2]. ese advantages make CFSTs popular in the civil engineering field and especially for prefabricated structures
Xu et al [22], Liu et al [23], and Tu et al [24,25,26] subjected multicell composite L- and T-shaped CFST columns to axial compression and low cyclic loading tests; the results showed that the columns with multicell composite materials have good mechanical properties
Xiong et al [29,30,31,32] and Xu et al [33, 34] systematically analyzed the mechanical properties of special-shaped CFST (SS-CFST) columns connected by different battens and established the bearing capacity calculation formulas corresponding to different stress states
Summary
Steel and concrete composite structures are widely used in civil engineering projects as they make full use of the superior material properties of steel and concrete [1]. e concretefilled steel tube (CFST) column has high bearing capacity, high ductility, strong fire resistance, and good seismic performance; formwork is not needed, so CFSTbased structures can be fabricated swiftly at relatively low cost [2]. ese advantages make CFSTs popular in the civil engineering field and especially for prefabricated structures. Zuo et al [18,19,20,21] ran axial and eccentric compressive tests and cyclic loaded tests on T-shaped and L-shaped CFST columns with binding bars to deduce their bearing capacity calculation formulas. Yang et al [27, 28] carried out axial compression tests on eight stiffened T-shaped CFST columns and investigated the mechanical properties and failure modes of the specimens. Xiong et al [29,30,31,32] and Xu et al [33, 34] systematically analyzed the mechanical properties of SS-CFST columns connected by different battens and established the bearing capacity calculation formulas corresponding to different stress states. In China, some prefabricated steel structure residential buildings adopt novel special-shaped concrete-filled steel square tube columns. Parametric studies were carried out based on the FEA models to establish the bearing capacity calculation formula for L/T-CFSST columns based on modification of the AIJ code. e calculation results were in close agreement with both FEA and experimental results, which suggests that the proposed model may provide a workable reference for practicing engineers and designers
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
