Uniaxial Eccentric Load Behavior of L-CFSST Composite Column

This study presents the mechanical behavior of L-shaped concrete-filled square steel tube (L-CFSST) composite columns under uniaxial eccentric compression. Nine specimens were tested and the effects of eccentricity, steel tube thickness, steel yield strength, and slenderness ratio were investigated regarding failure modes, ultimate load, load-lateral displacement curves, and load-strain curves. Test results showed that, under uniaxial eccentric load, these columns showed favorable mechanical properties and steel tubes showed strong cooperative working performance. There were two types of failure modes for these columns: local buckling of the steel tube or overall bending of the specimen. ABAQUS was used to simulate the loading process and the accuracy of the numerical simulation results was verified by comparing failure characteristics, load-displacement curves, and ultimate bearing capacity with the test results. The N/N u - M/M u curves of the columns under uniaxial eccentric load with different parameters were simulated by the finite element method. A simplified formula for predicting the N/N u - M/M u relationship was established based on the finite element analysis results, which might be a workable approach for designing L-CFSST composite columns in engineering practice.