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An experimental study was performed to obtain the data about the buckling strength of the columns using structural steel(SN490B) at high temperature. Two kinds of experiments under the centrally compressive load with rectangular cross-sections of thickness 10mm X width 26mm, (1)tests at constant high temperature, and (2), tests at increasingly higher temperature under a constant axial load. By the tests(1), the buckling loads of column models which were enforced axial edge compression at a constant-high temperature were examined. And, by the tests(2), the collapse temperatures of the column models at increasingly higher temperature under a constant load were examined. The results of these tests were compared on a chart of buckling curves, and the effect of creep strain on the buckling strength of the column models was investigated. Furthermore, numerical simulations of the tests were performed. And the results of the calculations clearly show that numerical analysis can be used to provide accurate predictions of the buckling characteristics of columns at high temperatures, when an appropriate mechanical model and data of steel materials at high temperature are used. Comparing the results of tests and analyses, the effects of creep strain (time effect) on the buckling characteristics of steel columns at high temperature are shown.

An experimental study was performed to obtain the data about the buckling strength of the columns using fire resistant steel (NSFR490A) at high temperature. Two kinds of experiments under the centrally compressive load with rectangular cross-sections of thickness 10mm×width 26mm, (1) tests at constant high temperature, and (2). tests at increasingly higher temperature under a constant axial load. By the tests (1), the buckling loads of column models which were enforced axial edge compression at a constant high temperature were examined. And, by the tests (2), the collapse temperatures of the column models at increasingly higher temperature under a constant load were examlned. The results of these tests were compared on a chart of buckling curves, and it is observed that the influence of the strain rate and P-Delta effect caused by creep strain on the buckling strength of the column models was very small. Furthermore, in order to explain this result, numerical analyses were carried out.

An experimental study was performed to obtain the data about the buckling strength of the column models using new metallic structural material (SA440B) at high temperature. Two kinds of experiments under the centrally compressive load with rectangular cross-sections of thickness lOmm X width 26mm, (1)tests at constant high temperature, and (2), tests at increasingly higher temperature under a constant axial load. By the tests (1), the buckling loads of column models which were enforced axial edge compression at a constant high temperature were examined. And, by the tests (2), the collapse temperatures of the column models at increasingly higher temperature under a constant load were examined. The results of these tests were compared on a chart of buckling curves, and it is observed that the buckling load of the tests(2) was larger than the tests(1) in the region of small slenderness ratio, and the result was reverse in the region of large slenderness ratio. Furthermore, in order to explain this result, numerical analyses were carried out, and the influence of the strain rate and P-Delta effect on the buckling strength of the column models under the elastic-plastic-creep behavior were confirmed.

An experimental study was performed to predict the effects of high temperature and creep strain on the buckling strength of steel columns at high temperature. In order to satisfy the purpose of this study, two kinds of experiments, (1)tests at constant high temperature and (2)tests at increasing high temperature under constant axial load were performed using the steel columns (SM490 J1S grade) with rectangular cross-section. In the tests at constant high temperature, the buckling strength at constant high temperature of SM490 steel column was clarified. The experimental result at constant high temperature and the computed result based on the nonlinear buckling theory showed good agreement. The results of two kinds of buckling tests were compared on a chart of buckling curves mutually, and the effect of creep strain on the buckling strength of steel column at increasing high temperature was evaluated.