Investigation on Mechanical Behavior of I-Section Steel Columns After Elevated Temperature

Abstract

This paper presents the experimental and numerical investigations on mechanical behavior of I-section steel columns after elevated temperature exposure. A total of twenty-six compression tests were carried out, in which one was under ambient temperature and the other twenty-five were under heating and cooling phase to study the influence of high temperature (400, 550, 700, 850, 1000°C) and high temperature duration (0.5, 1, 1.5, 2, 2.5 h) on mechanical behavior of the specimens. The failure pattern, axial load versus strain relation, axial load versus displacement relation and ultimate strength of the specimens were presented and analyzed. The test results showed that, high temperature duration had limited influence on the ultimate strength and other mechanical behaviors of the specimens, while the ultimate strength decreases with the increase of the maximum temperature the specimens suffered and some other behaviors also changed. The failure pattern of specimens after high temperature did not change compared with that of specimens under ambient temperature. The finite element models that have the same geometry with the test specimens were set up to compare with the test specimens and the results predicted from finite element analysis showed good agreement with that measured in test. Therefore, parametric study was carried out to investigate the influence of different section geometry on the ultimate strength of I-section steel short columns after elevated temperature. A new relationship for the ultimate strength for I-section steel short columns after elevated temperature was developed and proved to be reliable and accurate. What’s more, the effect of slenderness ratio on the stability coefficient of the columns was also investigated in the parametric study.