Behaviour of rectangular reinforced concrete members confined with GFRP sheets

ABSTRACT

Practical and economical reinforcement of existing structures can be achieved through external bonding of Glass Fibre Reinforced Polymer (GFRP) sheets to structural components. An experimental programme was developed to investigate strengthening effects of GFRP wrapping on rectangular concrete columns. Test variables included the wrapping scheme, presence of longitudinal sheets and the loading condition. Three types of loadings were considered: pure axial compression, pure flexure and combined flexure and axial compression. Axial compression versus flexure interaction diagrams were constructed. Specimens with and without longitudinal GFRP strips had similar pure bending capacities. The specimens with longitudinal GFRP reinforcement had balanced conditions with higher bending and lower axial compression resistance than specimens without longitudinal GFRP strips. Analysis of the experimental results revealed that the largest influencing factor that increased the compressive .strength of the specimens subjected to pure axial compression was the amount of transverse GFRP wrap. The largest contributing factor for increased moment resistance in specimens subjected to flexure and combined flexure and axial compression was the presence of longitudinal GFRP strips.