Finite Element Analysis On Hysteretic Behavior Of Reduced Beam Section Of Box Strengthen-joint Region Connection Of Fringe Frame For Weak Axis Of I-section Column

Currently research on connecting of I-shaped column in weak axis has remained rather limited and the traditional weak axis connection exist many problems. To solve these problems, associate professor LU Linfeng from Chang’an University proposed a new box strenthen-joint region for weak axis of I-section column. It has been tested to have good mechanical properties under monotonic loading. So this paper studied mechanical properties of the new joint connection in weak axis under cyclic loading by using finite element analysis software ABAQUS.Firstly, M?? curve, rotational stiffness, bearing capacity, rotative ductility and plastic rotation capacity of RBS and BASE specimens were studied. At the same time, according to European EC3 standard they were classified on joint stiffness; Secondly, some parameters, such as column axial compression ratio, slipping coefficient of friction surface, thickness and height of skin plate, steel material, weakening parameters of beam flange, thickness of column web, moment of strong axis and line stiffness ratio of beam and column were analyzed; Finally, the shortage of the RBS specimen was improved. The main conclusions as follows:1.The rotational stiffness and bearing capacity of RBS specimen joint were lower than that of BASE specimen joint, but RBS specimen had a better energy dissipation and plastic rotation capacity. The plastic rotation capacity of RBS specimen was greater than 0.04 rad, while that of BASE specimen was only 0.036 rad. In addition, RBS joint in sway and non sway frame all belonged to semi-rigid connections, while the BASE joint belonged to rigid connection in sway frame and belonged to semi-rigid connection in non sway frame.2.Excessive column axial compression ratio made P?? effect obviously and reduced the plastic rotation capacity. therefore, the axial compression ratio of the new RBS joint connection in weak axis was limited within 0.8; Slipping coefficient of friction surface had less effect on the mechanical properties of joint, but in order to prevent high-strength bolts prematurely slipping, it was recommended to use sand blasting on friction surface; the thickness of skin plate had great influence on the mechanical properties of joint, but the height of skin plate had a little influence on the mechanical properties of joint; Improving steel material could increase the bearing capacity of joint, but would reduce the ductility and plastic rotation capacity of joint; According to all aspects of comprehensive factors of the specimens, some suggestions were put forward on weakening parameters of the new RBS joint connection in weak axis; The thickness of column web had little impact on the mechanical properties of joint; The moment of strong axis had certain influence on weak axis connection; The line stiffness ratio of beam and column had a great influence on the mechanical properties of joint, so it was suggested that the line stiffness ratio of beam and column was not greater than 1.0.3.The way of making holes on beam flange was simple and less material damage to the hole, but it had less influence on the mechanical properties of joint; The way of welding vertical stiffener in joint region had great influence on the mechanical properties, and could reduce stress size and distribution of skin plate and weld position.