Behavior of square tubed reinforced-concrete short columns subjected to eccentric compression

• Square TRC short columns under eccentric compression were studied for the first time by testing 12 specimens.
• A new approach to determine the effective lateral confining pressure for TRC columns with square section was proposed.
• A numerical analysis model was developed to describe the eccentric compression behavior of square TRC short columns.
• Stress block parameters for square TRC members were suggested.
• The capacity interaction diagrams for square TRC short columns were obtained.

This paper presents the experimental and theoretical studies on square tubed reinforced-concrete (TRC) short columns under eccentric compression. The main parameters of the test specimens included eccentricity and width-to-thickness ratio of the steel tube. The axial load versus lateral deformation curves, stresses in the steel tubes and the observed failure modes were discussed. The test results indicated that the eccentrically loaded specimens exhibited good ductile behavior with a bending failure mode. A new approach to determine the effective lateral confining pressure for TRC columns with square section was proposed. A numerical analysis model was developed to simulate the mechanical behaviors of square TRC short columns. Valuable attempts were made to describe the variation rules between the parameters in stress block method for tubed concrete and the magnitude of confinement. Furthermore, the axial force versus moment capacity interaction diagrams of square TRC columns were calculated.