Prediction of Crack Width for Fiber-Reinforced Polymer-Reinforced Concrete Beams

Abstract

Use of fiber-reinforced polymer (FRP) bars to replace steel in reinforced concrete structures is being encouraged by many structural engineers, especially for its noncorrosive properties. The partial inferiority of the bond and mechanical properties for few commercial FRP bars, however, leads to wider, deeper cracks compared with those of steel-reinforced concrete structures. The characteristics of such cracks have significant interaction with the stresses and displacements induced in the concrete and the reinforcing bars crossing the crack (dowel action of bars), as well as on the contribution of the stirrups at crack location. Furthermore, because the dowel failure of FRP bars takes place in a brittle mode and lower magnitude of transverse displacement than steel, an accurate prediction of these characteristics is essential for a proper evaluation of beam serviceability, as well as its strength and failure conditions. Therefore, this paper presents an analytical formula that calculates the maximum crack width in FRP-reinforced concrete beams, taking into account both the bond and the mechanical properties of FRP bars.