Experimental and numerical investigations on the seismic response of built-up battened columns

Abstract

Built-up battened columns are lightweight and have a larger moment of inertia when compared with columns made by a single profile. However, these columns have shown poor seismic performance during past earthquakes. In this study, experimental and numerical investigations were focused on the seismic performance of these columns. A full-scale built-up battened column was subjected to quasi-static cyclic loading and its response was recorded. Furthermore, 81 built-up battened columns were simulated in ABAQUS software. The effects of batten spacing, batten thickness, chord distance, and axial force on the cyclic response of simulated columns were investigated. The obtained results indicated that the bulging of chord webs together with the local buckling of chord flanges were the main reason for the failure of columns. Besides, in all columns, the maximum stress in chords was almost twice larger than the maximum stress in battens. Furthermore, an increase in the batten thickness or a decrease in the batten spacing slightly increased the ultimate load of columns. Columns with a thicker batten exhibited a slightly smaller plastic deformation. The displacement ductility ratios of the built-up battened columns were all less than two even when they were subjected to an axial compression ratio smaller than 0.2. It was also observed that, in all columns, the ratio of ultimate load to the effective yield strength was less than 1.4.