Experimental and numerical analysis of compressed concrete elements confined with FRP composites

Abstract

Confinement of concrete by suitable selection of transverse internal reinforcement or by externally bonded reinforcement results in significant increase in both the compressive strength and the ductility of concrete subjected to compressive loading. Traditional confinement solutions have been developed using steel hoops or steel jackets and only recently fibre reinforced polymer composites (FRP) have been perceived as reliable confinement solutions for concrete elements. Extensive research projects have been performed since 1990s and theoretical and experimental results confirm the validity of confinement with FRP composites jackets. An experimental program has been initiated at the Faculty of Civil Engineering, the Technical University of Iasi, to evaluate the confining effect with glass fibre/epoxy and carbon fibre/epoxy composites. The influence of the material type and the thickness of FRP confining jacket were the variables involved.
The results obtained have proven the effectiveness of confinement solutions based on FRP composites. Both compressive strength and ductility of the confined specimens have shown dramatic increase compared to unconfined concrete specimens. The experimental set-up, the testing procedure and the main results are presented, emphasizing the influence of the composite nature and the thickness of the confining jacket.