Damaged Reinforced Concrete Beam Nip Bonded Steel Reinforcement Repair And Concrete Repair Experimental Research And Analysis

In cnginccring practice, the compression zone of the section of RC beam needs to be strengthened for the reasons of earthquake, conflagration, design, construction and use, which result in the damage of RC beam and compression sections of RC beam. Moreover, with the strengthening of the ultimate capability of over reinforced beams, the compression zone needs also to be strengthened. So the experimental study and theoretical analysis of RC beam repaired by bonding steel plates in compression zone of the section or by concrete are significant to engineering practice. The results of theoretical study and experimental analysis of damaging RC beams, which have been repaired by bonding steel plates in compress ion zonc of the section or by concrete, are presented in the thesis. The elastic solution to the normal and shear stress between external plate and concrete is obtained to the strengthening RC beams by bonding steel plates in compression zone. The interfacial stresses of plate and concrete in compression zone arc compared with those in tension i.one. Many factors affecting the interfacial stress between plate and concrete arc analyzed. Based on the test of 16 specimen strengthened by bonding steel plates in compression zone, the paper discusses the failure model, ultimate bearing capability and ductility. The formulas calculating bearing capacity by means of truss model are brought forward and the deflection property are analyzed through the study of 8 beams repaired with concrete. The paper puts up with the idea for the first time that the shear stress in compression zone between external plate and concrete of RC beam, which is 2/3 times the strength of that in tension zone. The work mechanism and failure model of RC beam strengthened by bonding plates in compression zone are different from that in tension zone. Based on truss model, the paper also proposes thc calculating formulas of bearing capacity for RC beam repaired by concrete for the first time. It shows close agreement between the experimental and theoretical results.