Research On Mechanical Behabior Of Declining Steel Tube Confined Concrete Column Shear Ring-Ring Beam Joint

In advantages of easy manufacture, construction and low cost, steel tube confined concrete column shear ring-ring beam joint has been widely used in the connection between steel tube confined concrete column and reinforced concrete beam in actual project in recent years.To meet the requirement of installing declining steel tube confined concrete column into architectural image, the joint that reinforcement concrete beam intersects declining steel tube confined concrete column by the angle of 75°has been formed in the structure of Sichuan broadcasting building. By now, there have not any experimental research and project for this joint. In order to test the factors of different reinforcement in ring beam, different ratio of ring reinforcement and longitudinal reinforcement, different cross-section height of ring beam and longitudinal beam, add strengthen reinforcement and tied reinforcement affected on load performance, failure pattern, bearing capacity and ductility of the declining column shear ring-ring beam joint, in this paper five two-thirds scale declining steel tube confined concrete column and ring beam combination were tested under static loading. It has provided experimental basis for the actual project.At the same time, the five specimens were simulated by nonlinear finite element procedure ABAQUS and contrast with the test results in this paper. It proof that the simulation of declining steel tube confined concrete column shear ring-ring beam joint by finite element computational method in this paper has good suitability and precision. Based on this, simulated specimens that change the cross-section size and reinforcement in ring beam to further discuss the load performance and failure pattern of declining steel tube confined concrete column shear ring-ring beam joint under static loading.The experimental and finite element analyse results indicate that there are two failure patterns, one occurred in frame beam, another occurred in ring beam. Regardless of the failure occurred in frame beam or in ring beam, the specimens also have high load carrying capacity and ductility because the failure started from the yield of the reinforcement.