FLEXURAL BEHAVIOUR OF CONTINUOUS CONCRETE BEAMS REINFORCED WITH FRP BARS

摘要

Continuous concrete beams are commonly used elements in structures such as parking garages and overpasses, which might be exposed to extreme weather conditions and the application of de-icing salts. In such structures, reinforcing continuous concrete beams with the non-corrodible FRP bars is a viable alternative to avoid steel-corrosion problems. However, the linear-elastic behaviour of FRP materials makes the ability of continuous beams to redistribute loads and moments questionable. In this paper, the experimental results of ten full-scale continuous concrete beams tested to failure, are presented. The specimens have rectangular cross section of 200*300 mm and continuous over two spans of 2,800 mm each. Steel, GFRP and CFRP b'ars were use as longitudinal reinforcement. Two materials were used for the transverse reinforcement, steel and GFRP stirrups. The main investigated parameters in this study are the amount and material of longitudinal reinforcement, the amount and material of transverse reinforcement and the spacing of used stirrups. Seven beams were reinforced with GFRP longitudinal bars, while two were reinforced with CFRP. A steel-reinforced continuous concrete beam was also tested to compare the results. The experimental results showed that moment redistribution in FRP-reinforced continuous concrete beams is possible if the reinforcement configuration is chosen properly, and is improved by increasing the amount of transverse reinforcement. Increasing the GFRP reinforcement at the mid-span section compared to middle support section had positive effect on reducing mid-span deflections and improving load capacity. Also, beams reinforced with GFRP stirrups illustrated similar performance compared to their steel reinforced counterparts. The test results were compared to the available design models and FRP codes. It was concluded that the Canadian code CSA-S806-02 could reasonably predict the failure load of the tested beams; however, it fails to predict the failure location.