The Study On The Relationship Between Interfacial Bonding Strength And Bearing Capacity Of Reinforced Concrete Beam

The excellent interfacial bonding between steel and concrete is the guarantee that the reinforced concrete beam can work well. But the research on the impacts of the interfacial bonding strength to the bearing capacity of reinforced concrete beams and whether steel and concrete have sufficient bond strength is not deep enough. This paper studies the bearing capacity of reinforced concrete beams by changing the interfacial bonding ways between steel and concrete, and has obtained some achievements.①This essay describes the preliminary achievements of bond-slip study, and analyzes the impacts of the interfacial bonding strength between steel and concrete on the bearing capacity of reinforced concrete beams theoretically.②Through brushing interfacial bonding adhesive in interface between steel bar (plate) and concrete, the author has realized the effective interface bonding between steel bar (plate) and concrete. Experiments shows that comparing to conventional bonding, the interface bonding strength between steel bar (plate) and concrete is greatly enhanced by adopting interface gluing approach:the shear strength of bonding interface increased by 7.5 times approximately, the flexural strength increased by 3.1 times, and the ultimate bonding strength in bond-slip increased by 43%.③The author has designed three kind of reinforced concrete beams by changing the interfacial bonding ways between steel and concrete, such as brushing bonding adhesive in the surface of steel, wrapping plastic film around the steel, and the conventional bonding. Furthermore, the bearing capacity experiments and the comparative analysis have been done at the same time. The experiments indicates that as the interfacial bonding strength between steel and concrete becoming higher, the rigidity of the beam become bigger, the values of cracking load and the ultimate load of the beam are much higher, and the mechanical properties of the beam are also much superior. Comparing to conventional reinforced concrete beams, cracking load values of the beams which were bonded with adhesive on the surface of steel increased by 14%, and its ultimate load values enhanced by 16%; the cracking load values of the beams which were bonded with plastic film around the surface of steel reduced by 24%, and its ultimate load values reduced by 31%. The experiment also proves that:in same load, the higher the interfacial bonding strength between steel and concrete is, the lower the steel strain is. At the same time, the height of compression zone of concrete become higher, and the plastic characteristic of the beam is more evident before destroy.④By means of finite element software, the theoretical analysis and test results were verified. The results show that:the bearing capacity of the established ANSYS model is much closer to the corresponding experiments, and the error range is within 10%, the effect is comparatively ideal. The summarized rules which are based on the computed results of different models are identical to the conclusions which were proposed by the author in the beginning of this essay.