Concrete Beams Strengthened with Externally Bonded FRP Plates

TLDR

The study presents the structural behavior of reinforced concrete beams strengthened with adhesively bonded FRP plates. The authors performed flexural tests on 2.3‑m concrete beams with varying internal reinforcement and external FRP or steel plate reinforcement, and modeled the behavior using 2D nonlinear finite‑element analysis with a concrete damage model. Experimental results closely matched the finite‑element predictions, and the authors suggest that plate detachment at ultimate loads is governed by a limiting principal stress at the concrete/plate interface.

Abstract

The structural behavior of reinforced concrete beams strengthened with adhesively bonded fiber-reinforced plastics (FRP) is presented. The experimental work included flexural testing of 2.3-m-long concrete beams with bonded external reinforcements. The test variables included the amount of conventional (internal) reinforcement and also the type and amount of external reinforcement. For comparison, some of the beams were strengthened with bonded steel plates. Theoretical analyses included 2D nonlinear finite-element modeling incorporating a "damage" material model for concrete. In general there were reasonably good correlations between the experimental results and nonlinear finite-element models. It is suggested that the detachment of bonded external plates from the concrete, at ultimate loads, is governed by a limiting principal stress value at the concrete/external plate interface.