Effect of Bond Properties on the Behavior of FRP-Strengthened RC Girders Subjected to Monotonic and Cyclic Loads


Externally bonded carbon fiber reinforced polymer (CFRP) is a feasible and economical alternative to traditional methods for strengthening and stiffening deficient reinforced and prestressed concrete bridge girders. the behavior of bond between FRP and concrete is the key factor controlling the behavior of these structures. Several experiments showed that debonding failure occurs frequently before FRP rupture and therefore the FRP strength can not be fully utilized. for design accuracy, the FRP strength must be reduced. This paper analyzes the effect of the bond properties on the response and failure modes of FRP-strengthened RC beams. a nonlinear RC beam element model with bond-slip between the concrete and the FRP laminates is used to analyze a test specimen subjected to monotonic and cyclic loads typical of seismic excitations, and to investigate the corresponding failure mode, and whether it is due to FRP rupture, debonding, or concrete crushing. the model is considered one of the earliest studies to numerically evaluate the behavior of FRP-strengthened girders under seismic loads. the model was also used to study the reduction factor of FRP tensile strength of simply supported strengthened RC girders due to de-bonding failure. This reduction factor seems to be directly affected by the bond strength between FRP and concrete interface. the study concludes with a numerical evaluation of the current ACI 440.2R guidelines for bond reduction factors.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Carbon fiber; Debonding; Degradation; Finite element analysis; Interface; Laminates; Seismic analysis

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

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Publication Date

01 Dec 2007

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