2D And 3D Rrregular Steel Partial Frame Research On The Elastic-Plastic Characteristic

There have been many complex shape building structures with the increasing number of high-rise steel frame structure,different requirements of various functions about structural spaces and the change of architecture aesthetics.There are a lot of unconventional joints with which the heights on either side are different and the force transferring mechanisms and deformation features of the node domain obviously are different from the conventional joints,so it is defined as special-shaped joint in the project.Recently,special-shaped joints have been used more and more widely in real projects.However,owing to the lack of theoretical support and sufficient experiences,the regulations for conventional joints are used in the process of designing special-shaped joints.This design method can only guarantee the strength requirements of special-shaped joints,but the safety of the structure can not be ensured.As a result,it is necessary to conduct researches on steel structure of special-shaped joints to investigate the mechanical performance and failure mechanism and propose proper design methods.The shaped joints of this paper are the exterior reinforcing ring beam-column special-shaped joints with different heights of beam in the plane and space and the advantages of the new special-shaped joint are to save constructional materials and manufacture conveniently.In the paper,finite element analysis by using ABAQUS create the model of exterior reinforcing ring beam-column special-shaped joints in the two dimensional plane and three dimensional space.The initial rigidity,bearing capacity and seismic performance of the new special-shaped joint separately.Elastic-plastic analysis is carried out on the steel special-shaped joints model with different heights of beam in the plane and measure the influence of geometric parameters such as beam height ratio,diameter-thick ratio,axial compression ratio,flakiness ratio of beam wing edge to shear bearing capacity and shear stiffness of exterior reinforcing ring beam-column node domain.Through the parameter analysis,the correction coefficient φ of shear bearing capacity formula of exterior reinforcing ring beam-column joints with different heights of beam of steel frame is put forward on the basis of shear bearing capacity formula of beam-column joints domain with the heights of steel frame in steel structure design specification in our country.Elastic-plastic analysis is carried out on the exterior reinforcing ring beam-column joints model with different heights of beam in the space and measure the influence of geometric parameters such as diameter-thick ratio,axial compression ratio,flakiness ratio of beam wing edge to shear bearing capacity and shear stiffness.Compare the shear bearing capacity and shear stiffness of the exterior reinforcing ring beam-column joints with different heights of beam in space and the same heights of beam in the plane.The finite element analysis results show that beam height ratio,thick cylinder diameter ratio,axial compression ratio and flakiness ratio of beam wing edge of exterior reinforcing ring beam-column joints with different heights of beam in the plane have apparent influence on shear bearing capacity and shear stiffness.The mean and variance values of the ratio is carried out from the moment bending moment multiplied the correction coefficient φ and bending moment calculated by finite element analysis and the values are 1.047 and 0.045.It is visible that the formula can better evaluate the correction coefficient φ and provides referential calculation formula to the design of exterior reinforcing ring joints in steel frame.That thick cylinder diameter ratio,axial compression ratio and flakiness ratio of beam wing edge of exterior reinforcing ring beam-column joints with different heights of beam in the plane have consistent influence on shear bearing capacity and shear stiffness.The force situation of the shorter side of beam in the plane have little influence on the shear bearing capacity and shear stiffness of beam-column node domain of different heights of beam in the space.The existence of the shorter side of beam in the plane can not increase the shear bearing capacity and shear stiffness too much and it is about 1.1 times.Therefore,the shorter side of beam in the plane can be used as a transverse stiffener of the node domain and it leads to the improvement of the shear bearing capacity and shear stiffness of the node domain.