Experimental Study on RC Walls with Opening Strengthened by Externally Bonded CFRP

Abstract

RC walls with an opening under eccentric axial loads exhibit cracks around the opening leading to a reduction in the ultimate strength of the wall. These cracks are mainly due to changes in the load path within the wall and stress concentration around the opening. Strengthening is usually required to enhance the ultimate strength of the wall, and carbon fiber–reinforced polymer (CFRP) is a suitable option for this purpose. In this paper, 18 one-third scaled RC walls with an opening were strengthened using seven distinct externally bonded (EB) CFRP layouts and were loaded up to failure under various support conditions. These walls were subjected to a uniformly distributed axial load with an eccentricity of one-sixth of the wall’s thickness. Crack patterns, failure modes, ultimate strength, and typical strain measurement of CFRP–concrete interface are presented and discussed in detail. The experimental outcomes revealed that the CFRP layout enhances the ultimate strength of RC walls by 14.0%–59.7% and 3.0%–40.8% for walls under one-way and two-way actions, respectively. The efficiency of each CFRP layout is also investigated to prioritize the appropriate layouts for each specific support condition.