Finite element (FE) analysis on strengthened reinforced concrete (RC) column clad with cementitious composite exposed to elevated temperature

Abstract

The application of Fibre Reinforced Polymer (FRP) as a strengthening material for Reinforced Concrete (RC) structures is gaining popularity. Conversely, the vulnerability of FRP to high temperatures is also a significant concern. Hence, a fire-resistant insulation layer is able to protect FRP and ensure that the strengthened RC structures satisfy the minimum fire requirement. Cementitious composite is reported to have better performance, higher economic value and greater sustainability than other commercialised insulation materials that can acquire minimum fire resistance. However, no previous studies have been found that discussed the thermomechanical behaviour of insulated FRPstrengthened RC structures exposed to ASTM E119 for fire endurance testing of structural assemblies. This study investigates the behaviour of a strengthened RC column layered with cementitious composite when heated up to 1000℃ for at least 2 hours. Finite Element (FE) analysis was used by simulating the model’s thermomechanical behaviour, and validated by the experimental data. The thermomechanical properties of the RC column strengthened with cementitious composite containing polypropylene (PP) fibres and Ground Granulated Blast-furnace Slag (GGBS) in different levels of thickness were assessed. The study found that 40 mm was the optimum thickness of the insulation layer applied to the RC column strengthened with Carbon FRP (CFRP) that acquired fire resistance of at least 2 hours.