Research On Strength Of Beam-column Joints In Concrete Structure

With the deepening of China's reform and opening up, the national economy has developed rapidly, the scale of cities is also expanding constantly, the urban land resources is more and more shortage. In order to build more effective use of building area on limited land,the multi-storey,sub-high rise and high rise reinforced concrete frame structure building has emerged, and gradually replaced block masonry structure and become the social mainstream architecture. With the implementation of the national 12th Five-Year Plan, the government is going to reinforce the transformation of villages in city, the construction of affordable housing and the construction of infrastructure, more and more reinforced concrete structure frame will be build. Although the theory of reinforced concrete structural design has been maturing, but in the structural design, nod design is always be a weak link. In each earthquake, there are always some reinforced concrete structures building collapsed for the improper design of beam-column joints .Currently, each country obtained their own standards of design and construction specifications by the framework of reinforced concrete box beam-column connection test specimens. According to the original experiment data and theoretical analysis, They also carried out some simulation experiments by the finite element on computer. But there is not a more unified mathematical model and a generally accepted theory. This paper follows from the principle of simple to complex, model of an actual project, and finite element analysis of all various types of nodes.This paper follows from the basic theory, describes the characteristics of steel and concrete, the stress - strain curve and the corresponding calculation theory. It also expound force and failure modes of frame joints, the factors of frame joint bearing capacity and the requirements of joint structure of the framework , the frame joint bearing capacity was studied theoretically. The features of frame joint construction were analyzed, and draw the corresponding treatment measures. Assume the steel in this article is the ideal plastic model and the concrete is plastic model. A 7-story and 3- span project is modeled by MIDAS. First of all, made the reliability analysis to the entire frame structure, the force of the framework have been studied; then some of the typical beam-column joints are modeled, analyzed and compared.Finally, the article discuss the unsolved problems in the reinforced concrete frame joints in finite element research. The results of this research provide some reference value to future reinforced concrete beam-column joints for finite element research,design and construction.