강관 내부보강 중공교각의 연성도 평가

초록

The ductility of circular hollow reinforced concrete columns with one layer of longitudinal and spiral reinforcement placed nearthe outside face of the steel tube placed on the inside face of the section is investigated. Such hollow sections are confines through the wall thickness since the steel tube is placed. The results of analytical moment-curvature analyses dor such lollow sections are compared with those for the circular section with the same diameter. In this study, moment-curvature analyses are conducted with Mander's confined concrete stress-strain relationaship in which the effect of confinement is to increase the compression strength and ultimate strain of concrete. The moment-curvature analyses confirmed that the ductility is primarily influenced on the ultimate strain. The variables influenced on the ultimate strain is the ratio and yield strength of confining reinforcement and the compression strength for confirmed concrete. From this ultimate strain - the transverse reinforcement ratio relationship, the transverse reinforcement ratio for circular hollow reinforced columns with confinement is proposed. The proposed transverse reinforcement ratio is confirmed by experimental results.