건설재료시공학연구실

Building material & construction lab.

Abstract

 Recently, it increases in use of CFT(Concrete filled steel tube, below CFT) because it an excellent internal force and deformation capacity. But, CFT column lose bearing capacity when steel tube is exposed under fire. In case of the Europe, Japan and America, it have been studied the fire-resistance performance of CFT to use actual specimen. Fire resistance performance of CFT column is determined to internal concrete at fire. Therefore, it is able to evaluate mechanical properties at elevated temperature though specimen reduce the scale.

 In this study, it is experimentally investigated in effects to use CFT Stub Column at elevated temperature. This study is aimed to study the effect of elevated temperatures ranging from 20 to 700℃ on mechanical properties of concrete according to strength of concrete and fiber mixing. Tests were conducted with □75×75×H200 mm CFT Stub Column and Ø100×200 mm cylinder specimens, which compared to that observed at 20℃.

 As a result, compressive strength decreased at 100℃, rose again at 200～300℃ and decreased over 300℃. But elastic modulus is decreased continually, and there were deferent as intended compressive strength at elevated temperature. Failure mode shows local buckling at a third of length.