Experimental study on shear strengthening of reinforced concrete box beam by CFRP
Document Type
Article
Publication Date
12-1-2020
Abstract
Numerous theoretical and experimental studies have been conducted on fiber-reinforced polymer (FRP) shear strengthening rectangular and T-section beams; however, few researches focused on box beam, which is widely used in bridge superstructures. This paper presented experimental study on shear strengthening reinforced concrete (RC) box beam by carbon-fiber-reinforced polymer (CFRP) with four common strengthening patterns. The CFRP strengthening schemes, failure modes, deflection, and effective strain in fibers were investigated and recorded. As for CFRP shear contribution, it showed best performance with a 52.7% increase for the specimen with a continuous U-jacket sheet. Besides, all the strengthened RC box beams exhibited the debonding of CFRP strips or sheets in the ultimate state. It was found that the maximum strains in fiber recorded from strengthened specimen were approximately 3000 mu epsilon accounting for 17% of the ultimate strain of CFRP sheet. The model in fib Bulletin 90 was used to predict CFRP shear contribution in the strengthened specimen, but it overestimated the values compared with experimental results because of higher effective strain calculated by model. A coefficient of 1.31 was therefore proposed for the equation of effective strain in the model, and the calculated CFRP shear strength by fib Bulletin 90 combined with modified effective strain was in good agreement with the experimental values.
Keywords
Box beam, Reinforced concrete, Shear strengthening, Carbon-fiber-reinforced polymer (CFRP), Effective strain
Divisions
sch_civ
Funders
Universiti Sains Malaysia [Grant No: 1001/PAWAM/814215]
Publication Title
Iranian Journal of Science And Technology-Transactions of Civil Engineering
Volume
44
Issue
4
Publisher
Springer Science and Business Media Deutschland GmbH
Publisher Location
GEWERBESTRASSE 11, CHAM, CH-6330, SWITZERLAND