CFRP Sheet로 보강한 사각형 콘크리트 기둥의 보강효과와 파괴특성에 관한 연구

Abstract

This study deals with the strengthening effect and failure mode of rectangular concrete column confined by carbon FRP sheet. The increase in axial compression capacity comes from the confinement effect of confined CFRP sheet. Because of the shape of rectangular concrete column, the confinement effect is smaller than that in circular column. For the experimental program, four parameters including the number of sheet, the size of column specimen, the ratio of height and width, coner rounding, and the transformation in shape from circular to square were selected to examine the strengthening effect and failure mode of each parameter. Experimental program comprised thirty three circular concrere column specimens for different eleven test column types. The compression test results confirmed that the confinement effect due to rolled and bonded CFRP sheet can considerably increase axial compression capacity in square concrete column. The resistance in compression capacity increased by 30% to 100% as the number of wrapped and bonded CFRP sheet increased from one sheet to three sheets. The strengthening effect of the parameters, the height and the diameter of circular concrete column decreased as they increased. The resisting capacity in axial compression was not affected by corner rounding unless it was larger than 30mm of radius. All square columns showed ductile behavior at the ultimate state. The transformation in shape from square to circular greatly affected the strengthening effect by 75% increase in axial compression capacity, compared to the original circular shape.