Semi-connected Node Model Of Concrete Filled Steel Tubes With Core Steel Angle Pilot Study

Concrete Filled Steel Tubular (CFST) structure has been developed rapidly in China since it was adopted in high-rise buildings in the 1980s last century because of its outstanding mechanical properties and good societal and economic beneficial results, especially in recent years. However, the problem of column-beam joint becomes difficulties in use, and restricts development of CFST to go step further. Even though ten or more types connections were put forward before, mature types of joints are also few. A new type CFST column and reinforced concrete beam corner joint, that is half-continuous joint is designed on the base of analysis advantages and disadvantages of column-beam joints at present, and it is modification of discontinuous side column-beam joint. The research in this article is based on CFST column middle joints research connected by core steel tube and new type CFST joints-side column joints research connected by core steel tube. The characters of new half-continuous joint are that the column is holed at the place of beam, and core steel tube, ring and vertical steel bar is placed in the zone of joint in order to strengthen the joint, while the longitudinal steel bars of beams go though the joint or are anchored in the concrete of the core zone.Through carrying out the module experiments and finite element analysis of two corner column-beam joints, the feasibility, basic mechanical properties and destroy patterns are researched. The results indicate that the new type joint has good mechanical properties, meets the demands of seismic design, that is strong column, weak beam, stronger joint. The finally destruct of model is caused by the CFST column, and the destruct of RC beams have little influences to the core zone of the joint. The most of joint core zone are still in elastic state when the model is destroyed, and the bearing capacity of joint has surplus. The hole has no influence to the continuity of the CFST column since the existence of core steel tube, ring and vertical steel bars, and the condition of joint is greatly improved.The bearing capacity of joint can be calculated by the method of superposition, and it is easy. Since the longitudinal steel bars of beams go though the joint or are anchored in the concrete of the core zone, the construction of joint is simple and the joint has big rigidity. The new type joint can be constructed with traditional construction method, and it can be adopted by reality engineering projects.