Finite Element Modelling of Reinforced Concrete Exterior Beam-Column Joint Retrofitted with Externally Bonded Fiber Reinforced Polymer (FRP)

Abstract

The issue of upgrading the existing civil engineering infrastructure has been one of great importance for over a decade. Deterioration of bridge decks, beams, girders and columns, buildings, and others may be attributed to ageing, environmentally induced degradation, poor initial design and/or construction, lack of maintenance, and to accidental events such as earthquakes. The infrastructure’s increasing decay is frequently combined with the need for upgrading so that structures can meet more stringent design requirements. Hence the aspect of retrofitting of civil engineering infrastructure has received considerable attention over the past few years throughout the world. External wrapping with fiber-reinforced polymer (FRP) is a promising solution for retrofit of beam-column joints due advantages such as high strength-weight ratio, corrosion resistance, ease of application, low labour costs, and no significant increase in member size over other strengthening techniques. Also, recent research has attempted to simulate the behaviour of reinforced concrete structures strengthened with FRP composites using the finite element method (FEM). But limited work is done on the use of FEM to analyse retrofitted beam-column joints. In the present study, finite element modelling of a reinforced concrete exterior beam-column joint retrofitted with externally bonded FRP is carried out with the help of commercially available software ANSYS 12.1. First, the control specimen is analysed and the results obtained are compared with an experimental study from the literature. Then, the specimen is retrofitted with externally bonded carbon-fiber-reinforced polymer (CFRP) sheets and analysed. The results from the retrofitted specimen are then compared with the results of the control specimen. It is found that for the control specimen, the values of yield load and ultimate load obtained in ANSYS are very close to the values obtained from the experimental study. Comparison between the load-deflection results obtained from ANSYS for control and retrofitted specimens shows that the yield load and ultimate load has significantly increased for the retrofitted specimen. This is accompanied by lower deflections for the retrofitted specimen as compared to the control specimen. The deflection ductility ratio and energy absorption has also decreased for the retrofitted specimen.