Research On The Layout And Optimization Of Lateral Bracing Of The Link Beam Section Of Eccentrically Braced Steel Frame (EBSF) Structures

As one of the basic types of frame structure system,eccentrically braced steel frame structure is widely used in buildings.According to the requirements of the code,the link beam section should be set with exposed lateral bracing(knee bracing)at the corresponding position.However,in practical engineering,the arrangement of lateral support is often subject to various restrictions due to site conditions,which brings great inconvenience to structural engineers to design eccentrically braced link beam section according to the code.Based on this,this paper proposes a kind of concealed lateral bracing,which can not only ensure the full performance of the link beam section,but also achieve the same effect as the lateral support according to the code.The main research works are as follows:1.Combined with the relevant theory of eccentrically braced steel frame in the code and its failure structure form,the preliminary design of concealed lateral bracing structure is carried out.The basic design principle of eccentrically braced steel frame should follow the structural principle of “strong column,strong bracing and weak link beam section”.2.Using ANSYS finite element software to build 10 single span eccentrically braced steel frame models.Considering the influence of the floor,the lateral bracing and concealed lateral bracing on energy dissipation capacity of the link beam section.The results show that the concealed lateral bracing can play the same role as the lateral bracing according to the code.Compared with the structure without considering the lateral bracing,its bearing capacity and energy dissipation coefficient are increased by about 5%;Compared with the structure without considering the floor,the bearing capacity and energy dissipation coefficient of the structure are increased by about 30%.3.Selecting 3 eccentrically braced steel frames with concealed lateral braces to carry out lateral loading tests in situ.Under the load of 1.2 times the design value of the code,there is no obvious lateral displacement of the link beam section,which indicates that the concealed lateral bracing has a good restraint torsion effect on the link beam section.4.Combined with the actual project,3 steel frame models are established by using SAP2000 finite element software,and the effects of floor,lateral bracing and concealed lateral bracing on the seismic performance of the structure are considered respectively.The results show that the damping coefficient of the structure with concealed lateral bracing is about 12%.At the same time,it also proves that the concealed lateral support structure proposed in this paper is practical in engineering.