Axial compression behavior of concrete-encased cellular steel columns: Fid-Bau Portal

Axial compression behavior of concrete-encased cellular steel columns

Anuntasena, Worakarn / Lenwari, Akhrawat / Thepchatri, Thaksin

Abstract This paper presents an axial compression behavior of bare and concrete-encased cellular steel (CECS) short columns. Three cellular steel configurations with different hole diameters and spacings were fabricated from the parent wide-flange hot-rolled steel shape. Eleven CECS columns using the cellular steel and four concrete-encased steel (CES) columns using the parent steel were tested to investigate the influence of the cellular steel configuration and the spacing between the closed stirrups. The test results of bare cellular steel columns showed that the failure was due to local buckling at the steel flanges and web at the hole section. The bare cellular columns exhibited the load-deformation relationship with less hardening behavior than the parent steel column. The proportional limit loads, yield loads, and maximum loads of all cellular steel columns were less than the parent column. The test results of composite columns showed that the CECS columns exhibited the failure mode, load-deformation relationship, and load-strain relationship similar to the CES parent columns. The weakening effect due to the circular openings was minimized by the concrete encasement. The compressive strength of CECS and CES columns increased as spacing of the closed stirrups decreased. A modified squash load equation is recommended for both CECS and CES composite short columns made with low-strength concrete, small amount of longitudinal rebars, and maximum stirrup spacing limit based on the ANSI/AISC360–16 specification.

Highlights • The bare cellular steel columns exhibited the load-deformation relationship with less hardening behavior than the parent wide-flange steel column. • The CECS columns exhibited the failure mode, load-deformation relationship, and load-strain relationship similar to the CES parent columns. • The effects of hole diameter and spacing used in the study reduced the compressive strength of the CECS columns with respect to the CES parent columns by less than 10%. • A modified squash load equation is recommended for both CECS and CES composite short columns made with low-strength concrete, small amount of longitudinal rebars, and large stirrup spacing.