Behavior of Concrete-Filled Hollow Structural Section Beam Columns to Seismic Shear Displacements

TLDR: In this paper, an experimental program to study seismic resistance of concrete filled hollow structural section (HSS) columns using normal-and high-strength concrete, respectively, is described.

Abstract: An experimental program to study seismic resistance of concrete filled hollow structural section (HSS) columns using normal- and high-strength concrete, respectively, is described. 24 concrete filled, 203-mm steel hollow-structural section, beam-column specimens were tested under constant axial compressive load and cyclic horizontal displacement. Lines of action of the horizontal displacements were either square, normal to a conventional axis, or across a diagonal. The investigation included determination of strength capacity, ductility, and flexural stiffness of concrete filled steel tube (CFT) beam-columns for compact and slender HSS sections. All HSS CFT columns tested showed excellent hysteretic behavior. Maximum moments occurred at drifts of 2-3% and ultimate drift ratios exceeded 7%. No local buckling before yielding was observed. Moment capacities of HSS CFT columns loaded with the plane of bending across the diagonal were only slightly less than those loaded with the plane of bending parallel to a square side, reducing the need for elaborate procedures to calculate moment capacities at orientations between 0 and 45 deg.