Analysis Of The Seismic Behavior And Structural Optimization Of Beijing CBD Cultural Center

Based on the background of Beijing CBD Cultrual Center,this paper presents details of study on the structural optimization and the seismic behavior of Beijing CBD Cultural Center.Beijing CBD Cultural Center,is located in Chaoyang District,Beijing,China,where the fortification intensity is 8.It is constructed by using a braced-steel-frame structural system,with a height of 46 m and a plane size of 136m×47m.The building has the following challenges:(1)Because of its complex structural arrangements,at least two different mechanical models are required for structural analyses and comparisons.(2)The lateral force resisting element is less which leads to the weak latera l stiffness.(3)An appropriate tranfer structure is required to solve the problem that some columns of the frame cannot fall to the ground.In this paper,Midas Gen and ABAQUS are used to calculate and analyze the structure.(1)Preliminary analysis.The paper uses Midas Gen and ABAQUS to develop a 3-dimensional finite element(FE)model for undertaking elastic analyses of the dynamic behavior in frequent earthquakes,including the modal analysis and response spectrum analysis.Indicators obtained from Mid as Gen and ABAQUS have been examined and compared.It can be concluded that the indicators all satisfy the requirements of building codes.(2)Time-history analysis.For buildings which possess either complex shapes or complex structures,the time-history analyses are required.This paper uses ABAQUS to undertake analyses of the dynamic behavior of the building,including elastic time-history analyses in frequent earthquakes and elastic-plastic time-history analyses in rare earthquakes.Indicators have been examined.It can be concluded that ABAQUS is adequate for time-history analyses and the indicators from the time-history analyses all satisfy the requirements of building codes.(3)Analyses of the buckling restrained braces.The lateral force resisting element of Beijing CBD Cultural Center is less which leads to the weak lateral stiffness.To solve the problem,the buckling restrained brace(BRB)will be used.This paper uses Midas Gen to develop steel frame models with conventional braces and buckling r estrained braces for undertaking ananlyses of the dynamic behavior of this building,including modal analyses and elastic-plastic time-history analyses.According to the comparison of calculation results,BRBs can absorb more energy in rare earthquakes and improve the seismic behavior of the structure.(4)Analyses of the selection of the transfer structure.To solve the problem that some columns of the frame cannot fall to the ground,the structure has transfer beam-columns on the east and west sides.This paper presents a box-type-beam transfer and a truss-type-beam transfer structure and presents details of using Midas Gen to develop two models of modal analyses and response spectrum analyses.According to calculation results and considering the factors such as economic and the convenience of construction,the box-type-beam transfer structure is more suitable for the building.