SHEAR STRENGTH OF RC BEAMS REINFORCED WITH FRP STIRRUPS

摘要

The use of Fiber-Reinforced Polymer (FRP) as reinforcement for concrete structures is rapidly increasing. However, limited research has been carried out to investigate the shear behaviour of concrete beams reinforced with FRP stirrups. An experimental program investigating the structural performance Fibre-Reinforced Polymer (FRP) stirrups as shear reinforcement for concrete structures is being carried out at the University of Sherbrooke. This paper presents the test results of three large-scale reinforced concrete T-beams of 7.0 m long and 180 mm web width (Simulating the New England Bulb Tee beams that are being used by the Ministry of Transport of Québec) reinforced with FRP and steel stirrups. The first beam is reinforced with CFRP stirrups; the second one is reinforced with GFRP stirrups; and the third one with steel stirrups. All the used stirrups were of 9.5 mm diameter spaced at 300 mm (d/2); where d is the effective depth. The test specimens were reinforced in flexure with nine seven-wire steel strands of 15.4 mm-diameter. The test results showed the adequate performance of the used FRP stirrups. However, compared to the test results, the provisions of the Canadian Highway Bridge Design Code, CHBDC (CSAS6-06) provided a conservative shear strength prediction for the tested beams and beams from literature due to the specified strain limit for FRP stirrups (2500 microstrain).