RESEARCH ARTICLE
Experimental Study on Structural Degradation of CFRP Strengthened RC Beams Subjected to Weak Interfaces
Xiaogang Wang*, Wenwu Fan, Xiangbo Du, Zhaoxin Fang
Article Information
Identifiers and Pagination:
Year: 2016Volume: 10
First Page: 384
Last Page: 401
Publisher ID: TOCIEJ-10-384
DOI: 10.2174/1874149501610010384
Article History:
Received Date: 3/11/2015Revision Received Date: 9/02/2016
Acceptance Date: 3/04/2016
Electronic publication date: 29/07/2016
Collection year: 2016
open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution-Non-Commercial 4.0 International Public License (CC BY-NC 4.0) (https://creativecommons.org/licenses/by-nc/4.0/legalcode), which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
Abstract
The performance of corroded reinforced concrete (RC) beams strengthened with externally bonded carbon fiber reinforced polymer (CFRP) materials may be affected by a weak interface caused either by defective bonding between the new and old concrete in the case of cover replacement or by expansive cracks in the case of direct application. To investigate this effect, thirteen strengthened beam specimens with preinstalled horizontal weak interfaces were designed and tested in monotonic bending. Through analysis of the experimental results, in terms of load deflection curves and the derived bond stress distribution, it was found that intermediate delamination was induced by the weak interfaces, which greatly impaired the integrity of the strengthening system and eventually led to CFRP integral debonding without lateral confinement. Degradation of the shear transfer ability through the interface can be expected due to interfacial weakening, increasing of the CFRP reinforcement ratio and reduction of cover thickness. Crack-induced weak interfaces caused less serious damage at the early stage but induced more dramatic degradation as cracks expanded. U-strip confinement was found to be effective in improving the structural performance of the strengthened beam and preventing CFRP integral debonding. Nevertheless, intermediate delamination cannot be prevented, increasing the risk of CFRP premature rupture and end anchorage failure.
