NUMERICAL INVESTIGATION OF FRP-STRENGTHENED REINFORCED CONCRETE BEAMS AT HIGH TEMPERATURES

Abstract

Fiber reinforced polymers (FRP) strengthening systems are mainly used to retrofit existing and deficient structural members. The performance of such strengthened structures at elevated temperatures is a critical issue that threatens the safety of the structure. Published research includes experimental testing of reinforced concrete (R.C) beams strengthened using FRP and subjected to fire tests. However, there is a need for numerical tools that simulate the performance of these FRP-strengthened elements in case of fire. This research work presents numerical modelling and nonlinear analysis conducted to assess the performance of reinforced concrete beams strengthened with externally bonded carbon FRP sheets when subjected to standard fire conditions. Finite element model using the general purpose software ANSYS 12.1 is developed and validated with experimental results published in the literature by other researchers. The developed finite element model achieved good correlation with the experimental results. Further, application of the validated finite element model is extended into a parametric study to explore the influence of different variables on the performance of the FRP system when subjected to fire. Different aggregate types, moisture contents, concrete cover thickness, insulation material types and insulation material thickness are included in the study. The developed finite element model is thus regarded a valid and economical alternative to experiments for prediction of the performance of FRP strengthened and insulated R.C beams under fire conditions. Additionally, it can be used for estimation of the fire rating of such structures as well as for design of adequate fire protection layers.

Keywords

• Fire performance
• Thermal insulation
• Numerical modeling
• Fiber reinforced polymers (FRP)
• Reinforced concrete beams
• Flexural strengthening