Experimental Study On The Bending Resistance Of Damaged Reinforced Concrete Beame Reniforced By Carbon Fibre

The problem of the shortage of bearing capacity and durability exists in servicereinforced concrete, around the world, more and more extensive attention is paid to thathow to use the effective reinforcing and repairing measures to improve the bearingcapacity of the structure and prolong its service life. In recent years, carbon fiberreinforced polymer (CFRP), due to its excellent physical and mechanical performances,is widely used to reinforce and repair reinforced concrete structure, and relevantresearches have been done by many scholars. At present most studies of CFRPreinforced concrete beams are about the intact experimental beams, and those of thedamaged experimental beams are much less, while those of the reinforced concretebeams in chlorine diffusion environment are really rare. Taking the common damageand degradation state existing in service concrete into account, it has importanttheoretical and engineering significance to further research the reinforcementperformances of CFRP to damaged reinforced concrete beam.In this paper, combined with ANSYS finite element simulation, the detail researchof the bending-resistance performances of CFRP enhancing damaged reinforcedconcrete beam is made by test. Main ideas are as follows：1、Based on previous researches, the theoretical analysis of bending-resistanceperformances of CFRP strengthening reinforced concrete beams is made, andtheoretical calculation method of bending-resistance capacity which has consideredsecondary stress and corrosion damages is deduced;2、After different degree mechanical damages, strength the reinforced concretebeams with CFRE and carry out experiments of bending-resistance performances onthem, then compare theoretical calculation results with experimental ones. The resultsshow that the bending-resistance capacity of damaged reinforced concrete beam iseffectively improved, and the degree of improving is connected with the severity ofmechanical damage. After strengthening, the bending-resistance capacity of reinforcedconcrete beam basically reaches or exceeds that of the beam without strengthening. Atthe same time, its bending-resistance rigidity is also improved to some extent. 3、 Using ANSYS program, the nonlinear finite element analysis ofbending-resistance performances of the mechanical damaged beams which have beenreinforced with CFRP is proceeded. The results of finite element analysis better matchwith the test results. It shows that the finite element model based on the simplifyingassumption is reasonable, and it was applicative in a certain extent for reinforcingdesign of the damaged reinforced concrete beams.4、The bending-resistance of damaged reinforced concrete beams which have beenstrengthened by CFRP is primarily studied by experiment in the chloride diffusionenvironment. The results show that either strengthening the reinforced concrete whichhas endured mechanical damage-chloride diffusion with CFRP or after CFRPstrengthened reinforced concrete enduring different duration of chloride diffusion, thereinforcement is relatively effective on improving bending-resistance capacities of thebeams, but the reinforcement effects are influenced by the mechanical damage andenvironmental corrosion.