Title: Active Confinement of RC Columns with External Post-tensioned Clamps

Author(s): Julian D. Rincon, Kinsey C. Skillen, Santiago Pujol, Yu-Mei Chen, Aishwarya Y. Puranam, and Shyh-Jiann Hwang

Publication: Symposium Paper

Volume: 358

Issue:

Appears on pages(s): 106-125

Keywords: drift capacity, external post-tensioned clamps, RC columns, retrofit, shear strength

DOI: 10.14359/51740233

Date: 9/1/2023

Abstract:
There are too many reinforced concrete (RC) columns built before mid-1970s without sufficient transverse reinforcement. By now, we understand quite well the importance of transverse reinforcement in allowing a column to maintain its integrity under large displacement reversals in the nonlinear range of response. Poorly confined RC columns undergo a fast decay in resistance due to formation of criss-crossing inclined cracks, which can cause an abrupt failure or more gradual disintegration and trigger collapse of the structure. Those columns need to be strengthened to increase their drift capacity. Although there are several alternatives to retrofit RC columns, they often require specialized workmanship and equipment, and involved installation procedures. An easy-to-design and easy to implement retrofit technique is examined here. It consists of external post-tensioned clamps fastened around the column. Results of tests on full-scale RC columns furnished with the proposed clamps suggest the clamps can be effective in increasing column shear strength and drift capacity.