강섬유 콘크리트 혼입율에 따른 내부앵커형 콘크리트 충전기둥 내화성능에 관한 해석적 연구

Abstract

Professor, Department of Architectural Engineering, University of Seoul, Seoul, 02504, KoreaAbstract - Concrete filled steel tube system has two major advantages. First, the confinement effect of steel tube improves the compressive strength of concrete. Second, the load capacity and deformation capacity of members are improved because concrete restrains local buckling of steel tube. It does, however, involve workability problem of using stud bolts or anchor bolts to provide composite effect for larger cross-sections. While the ribs inside the columns are desirable in terms of compressive behavior, they cause the deterioration in load capacity upon in-plane deformation resulting from thermal deformation. Since the ribs are directly connected with the concrete, the deformation of the ribs accelerates concrete cracking. Thus, it is required to improve the toughness of the concrete to resist the deformation of the ribs. Welding built-up tubular square columns can secure safety in terms of fire resistance if the problem are solved. This study focuses on mixing steel fiber in the concrete to impro ve the ductility and toughness of the columns. In order to evaluate fire resistance performance, loaded heating test was conducted wit h 8 specimens. The behavior and thermal deformation capacity of the specimens were analyzed for major variables including load ratio. The reliability of heat transfer and thermal stress analysis model was verified through the comparison of the results between the test and previous study.Keywords - Fire resistance, Composite column, Steel-fiber, Heat transfer, Thermal stressNote.-Discussion open until August 31, 2016. This manuscript for this paper was submitted for review and possible publication on June 22, 2015; revised December 22, 2015; approved on January 13, 2016.Copyright ⓒ 2016 by Korean Society of Steel Construction