Axial Compressive Behavior of Concrete-Encased High-Strength Steel Angle Columns

Abstract

This study investigated the compressive behavior of concrete-encased high-strength steel angle columns (Fy=718 MPa). Axial compressive tests were performed on six composite columns with different angle sections and confinement details. The results showed that the failure mode of the columns was local buckling of the angle legs and crushing of the confined core. Local buckling and concrete confinement significantly affected the compressive strength and ductility. The test strengths were compared with the theoretical strengths computed using the plastic stress distribution method. For analytical investigation, effective stress–strain models of the steel angle and concrete are proposed to account for the local buckling, spalling, and confinement. Through the strain-compatibility analysis based on the proposed models, the contributions of the angles, unconfined cover, and confined core to the compressive strength varying with deformation were investigated. Based on the investigation results, recommendations for the design and detailing of concrete-encased high-strength steel angle columns are given.