Performance And Parameters Analysis Of Force-Transforming Plates Outside Box Column's Frame Joint With Beams Of Different Height

For twenty years, more and more beam-column joints' retrofitting and strengthening methods have been proposed to avoid brittle failure of panel zone. As the key part of the beam-column connection in the structural steel frame, its performances influence the responses of the whole frame under loading. In structural design, the height of the beam of a steel frame should be designed according to loads and deformation of structure. As to the central joints of steel frame, the connection between steel beams may be unproportioned to the height of the beams, which will lead to the performance of joint with beams of different height different with that of normal joint. Therefore, it is necessary to carry out stress analysis for joints with different beam heights in steel frame.This paper presents a joint transferring forces outside box columns with beams of different heights. By widely used finite-element-method program ANSYS, three groups of joints transferring beams' forces outside box columns with beams of unequal height were designed. The calculative results compared with those of traditional joints and only add upper force-transforming elements joints, by comparing their load-displacement curves, distributions of Von-Mises stresses and stresses path, effectiveness of the adding force-transforming elements was proofed. This paper designs 83 specimens to analyze the joints and make the comparison by ANSYS. The main research can be listed as follows:1. The traditional joints and rigid joints transferring forces outside box columns with beams of same height can be compared by the numerical simulation. By comparing their load-displacement curves, distributions of Von-Mises stresses and stresses path,effectiveness of the adding force-transforming elements was proofed, and comparing with the test results, the correctness of the model can be proved.2. The traditional joints with beams of different heights, joints of only adding upper force-transforming elements, and joints transferring forces outside box columns with beams of different heights by adding upper and lower force-transforming elements can be compared by the numerical simulation, by comparing their load-displacement curves, distributions of Von-Mises stresses and stresses path, effectiveness of the adding upper and lower force-transforming elements was proofed.3. In this paper, the width and thickness of adding upper force-transforming elements would be the key parameters of steel frame joints. By analyzing the models with different thickness and width of adding upper force-transforming elements, and puts forward the optimal range of design parameters.4. The designs of lower force-transforming elements were different with joints transferring forces outside box columns with beams of same height, the lower force-transforming elements includes cover plates and web plates. The width of cover plates, the thickness of cover plates and web plates would be the key parameters of joints transferring forces outside box columns with beams of same height. By analyzing the models with different thickness and width of adding lower force-transforming elements, and puts forward the optimal range of design parameters.5. Direction of further research about the performance analysis of this kind of new joints is found, which can provide some basic for the practical engineering.