Premature failure of RC continuous beams strengthened with CFRP laminates

摘要

This paper investigates the premature failure of carbon fibre reinforced polymer (CFRP) laminates attached to the tension face of continuous reinforced concrete beams. Sixteen reinforced concrete continuous beams with different arrangements of internal and external reinforcement were tested to failure. All test specimens had the same geometrical dimensions and were classified into three groups according to the internal steel reinforcement. Each group had one unstrengthened control beam designed to fail in flexure. The length, thickness, form and position of the CFRP laminates were the main parameters investigated. Three premature failure modes of beams with external CFRP laminates were observed, namely laminate rupture and laminate separation and peeling failure of the concrete cover adjacent to the laminate. Comparisons between failure loads obtained from experiments and the results of theoretical analysis are presented. The ductility of all strengthened beams was reduced compared with that of the respective unstrengthened control beam.