Title:
Bond Mechanism of Near-Surface-Mounted
Fiber-Reinforced Polymer Bars for Flexural
Strengthening of Concrete Structures
Author(s):
Tarek K. Hassan and Sami H. Rizkalla
Publication:
Structural Journal
Volume:
101
Issue:
6
Appears on pages(s):
830-839
Keywords:
beams; bond; concrete; fiber reinforcement; strength
DOI:
10.14359/13458
Date:
11/1/2004
Abstract:
This paper presents both experimental and analytical investigations undertaken to evaluate bond characteristics of near-surface-mounted (NSM) carbon fiber-reinforced polymer (CFRP) bars. A total of eight concrete beams, strengthened with NSM CFRP bars, were tested under monotonic static loading. Different embedment lengths are studied to determine the development length of the fiber-reinforced polymer (FRP) reinforcement. The performance of two different adhesives used to bond the bars to the surrounding concrete is examined. A general methodology to evaluate the development length of NSM FRP bars of different configurations and types of fibers is presented. A quantitative criterion governing debonding failure is established. The proposed bond model assumes linear elastic behavior for the concrete, adhesive, and the NSM FRP bars, following the same philosophy of the ACI provisions for bond analysis and design. The proposed analytical model is validated by comparing the predicted values with test results as well as to nonlinear finite element modelling. The influence of key parameters, including the thickness of the adhesive cover, groove width, groove spacing, and internal steel reinforcement configuration, are discussed.