Study On Mechenical Behavior Of The Steel Tube Confined Concrete Column-Ring Beam Joint

In advantages of reliable forced,easy to make,convenient construction and low cost, the steel tube confined concrete column ring beam joint with shear ring has been widely used in the connection between steel tube confined concrete column and reinforced concrete beam in the steel tube confined concrete structures in recent years. Since the ring beam joint has been proposed, too many static and low cyclic experiments have been made. The experimental findings have a high reference value. For absence of the finite element numerical simulation, we cannot know each parts detail visually.On the basis of the research of other scholars for this problem, the general software-ANSYS has been used to simulate the ring beam joint, so as to know the mechanics mechanism,force transmission path and the ultimate failure mode. The main analysis of the content and results are listed as follows:1.We have designed four joint, JD-1 is designed for the comparison, and the others consider the cross-section size, reinforcement and the shear ring number. The results indicated that the carrying, capacity of ring beam can be differently enhanced by enlarging the ring beam cross-section, improving the reinforcement ratio and increasing the numbers of the shear ring. The mechanical behavior of ring beam joint, which the cross-section of ring beam and frame beam is not equivalent, is better than the other three.2.The mechanics mechanism of ring beam joint has been simulated under the direct shear, in order to understand the concrete cracking and ultimate failure mode. The analysis obtained the local pressure bearing capacity.3. Based on the model in the references, this paper proposed a new ring beam joint with stiffener. The analysis showed the stress concentration got a significant improvement at the intersection area of the frame beam and ring beam, as part of the moment was transmitted to ring beam through the stiffener. The potential of the carrying capacity of ring beam has been highly acquired. Most of the longitudinal reinforcement and stirrups in ring beam have yielded, when the joint destroyed, and plastic hinges occurred in the end of the frame beam. This is a bending damage. The improved ring beam can greatly improve the capacity of the joint.