Research On The Mechanical Properties Of Frame-core-outrigger Structural System

Due to the frame-core-outrigger structural system can make good use of the mechanical properties of materials、effectively resistance to lateral force、good social and economic benefits,so a lot of building use this system to build ultra-high-rise building.In abroad there is a dispute that the system can built in the earthquake zone,but in china most use this system’s building was built in the requiring seismic resistance’s areas,the system has become a hot issue in the theoretical analysis and engineering practice.Wuhan Center tower has4basements,88floors above the ground,438meters, using frame-core-outrigger structural system, the hybrid structure of steel and concrete. This article rely on the theoretical results of the relevant literature, the engineering background of Wuhan Center tower, using the finite element method to built three-dimensional finite element, studied structural model of seismic and wind performance,use the method of deconstruction of the structure, access to affect the system by the force of the key factors and their detailed study. The analysis studies the following conclusions:1. Effect with wind loads and multi-earthquake,the lateral displacement curve bending,displacement between the reinforcing layer parts of the structure layer,the layer shear and overturning moment will be a mutation,with outrigger truss parts of the strengthening layer mutation is more evident,the structure will form a weak layer;2. The frame-core-outrigger structural system’s critical parameters is:the axial stiffness of the pillars, the thickness of the core tube, the stiffness of the ring truss and outrigger truss number, location and stiffness;3. The pillars axial stiffness increase can significantly improve the overall stiffness of the structure, but exceed a certain limit the lateral displacement of the structure is no longer.Increasing the ratio of the core tube wall thickness, the lateral stiffness improvement of the structure is not obvious, and the wall thickness increased seismic and unfavorable, should be reasonable control of the concrete thickness ratio and wall thickness; 4.Ring truss little contribution to the lateral stiffness of the structure by changing the size of the ring truss, and improve the overall stiffness of the structure is not obvious; as outriggers number increase, the structural cycle, vertex displacement, displacement between layers, layerthe drift angle decreases, but decreases the magnitude of decrease with the increase in the number of overhanging truss; gradually increase the stiffness of the outrigger truss structure of the cycle, will reduce the lateral displacement, the framework and the core barrel to bearoverturning moment will increase the number, location and stiffness of outrigger truss structure design should be set.The result of this paper is provide a theoretical value for the frame-core-outrigger structural system,and provide some reference value for the design and analysis of similar high-rise buildings.