CONFINEMENT MODEL FOR CAPSULE-SHAPED CONCRETE COLUMNS

摘要

Capsule-shaped columns occur in bridge piers, and in building structures, rectangular columns could be re-profiled as capsule-shaped columns to capitalize on the strengthening effect of FRP confinement. In this study, the confinement effect of externally bonded FRP sheets on the axial load capacity of capsule-shaped concrete columns was investigated. A confinement model, which considers the two circular end segments of the capsule-shaped column section to be subjected to triaxial compression while the remaining rectangular segment of the section to biaxial compression, is proposed. A series of axial compression tests was carried out on 16 specimens with section aspect ratio ranging from 1 to 4, and number of plies of CFRP sheets varying from 0 to 3. The axial load capacity of the column increased with the amount of FRP sheets but it decreased with the section aspect ratio. The proposed confinement model was found to predict the test results well.