Axial compression behavior of prefabricated L-section thin concrete encased steel short columns

Abstract

A prefabricated L-section thin concrete encased steel (L-TCES) column, which could be prefabricated in shop, connected on site, and not convex out of wall, was proposed. Changing the proportion of steel sectional area, concrete strength, stirrup spacing and the concrete encasement thickness outside the flange, experimental and numerical investigations were conducted on the axial compression performances of the proposed composite column, and the failure modes, load-displacement curves, load-strain curves and characteristic resistances were analyzed. According to the results, the concrete encasements and reinforcements can restrain the steel buckling, and increasing the proportion of steel sectional area or the concrete strength can improve the ultimate resistance and stiffness of the column. Increasing the thickness of concrete encasement outside the flange could prevent the concrete from cracking, and compared with steel column, the resistance of steel in the composite column can be more fully utilized under the ultimate load. The formulas to calculate the design and ultimate resistance for the composite column with closed stirrup were proposed, providing results with satisfactory accuracy. The simplified model of load-displacement curve was proposed and validated against the test results.