Mechanical Performance Research And Application Of Bottom-Through-Diaphragm Top-Ring Joint Connecting Square Steel Tube Column And H-Shaped Steel Beam

The steel structure dwelling houses, as a kind of energy saving and environmental protecting green building, have the advantages such as good performance under seismic action, less construction pollution, low integrated costs and short construction period. It meets the demand of the housing industrialization and the requirement of the sustainable development. With the growth of Chinese steel production and continuing improvements in construction technology and informatization management level, the development of assembled steel structure dwelling houses has become a new proposition in the process of housing industrialization in our country.The beam-column connection, which plays the role of transmiting the moment and shear, is the key to steel structure design and its performance directly affect the overall structure of reaction. Square steel tubes, as column components, are superior to H-shaped steel columns in the mechanical performance and the convenience of construction layout. However, due to the limitation of section form, the connection with the H-shaped steel beams connection often has some problems of appearing metope, occupying buildings use space and affecting appearance. Therefore, in order to improve the connection of the square steel tube column and H-shaped steel beam and satisfy the demands of assembled steel structure housing development, a new type connection of the bottom-through-diaphragm top-ring joint connecting square steel tube column and H-shaped steel beam is presented in this paper.For the purpose of investigating the mechanical behavior of the new type connection, five specimens are designed and the cyclic loading tests of the specimens are carried out in this paper. The failure process and feature of each specimen were described and load-carrying capacity, ductility, energy dissipation capacity were analyzed. The results show that the five specimens all occurred obvious plastic deformation on the steel beam flange before failure, and the steel column was not found to have obvious deformation, it is good to achieve "strong column weak beam, strong connection weak component" design idea; the plump load-displacement hysteresis curves of the specimens indicate that they all have good energy dissipation capacity.Based on the large finite element analysis program ANSYS, five new type connections were numerical simulated, and the results of failure modes, hysteresis behavior, ultimate load and stress distribution were compared with the experimental results, which showed that the ANSYS results are consistent with the experimental results. Through the analysis of stress distribution of steel beam flange, external-diaphragm and through-diaphragm, it was proved that it is prone to occur stress concentration in the hole location and the corner of column, so in the practical engineering the welding seam quality at these positions should be guaranteed to avoid connection brittle failure; since the influence of welding was not taken into consideration in the ANSYS, the load can be applied until the full development of panel zone plasticity, and in the late loading phase it was clearly that the cantilever beam with the T section steel can enhance the shear capacity of the panel zone and improve the mechanical performance of beam-column connections.The M-B curve of new type connection was drawn on the base of the ANSYS results and experimental data, and the initial rotational stiffness was calculated which showed that the new type connection belongs to semi-rigid connections; the results show that the out-of-plane deformation rigidity of steel tube wall in the new type connection is weak, which is prone to occur local buckling during the plastic phase, therefore it is particularly important to set T section steel to enhance the panel zone. This paper fitting out a suitable moment-rotation relation model, and through comparing with the ANSYS results and experimental data, showed that the proposed bending moment-corner relation model has good accuracy and can be used for reference in the new type connection design and practical application.