Research On Integral Stability Of High-rise Steel Frame Structure

As an important bearing structure system, steel frame structure is widely used in housing,office and entertainment buildings. According to the characteristics of steel structure itself, thestability of steel structure becomes an outstanding problem, and instability has been one of themain reasons which could lead catastrophic damage. Therefore, stability analysis of thestructure becomes an important step of the design. In this thesis, research on the integralstability of the steel structure was made to study the failure mode and effect factors of theintegral structure stability. It could provide some evidence for the design of steel framestructure.Firstly, structure design of certain high-rise residential building of Nanjing was made.Then, the structure arrangment and the section size were determined. The finite elementsoftware ANSYS was used in the eigenvalue buckling analysis of the highrise steel framestructures, through the linear buckling coefficient and buckling modes, the toplimit of thenonlinear buckling load and the shape of buckling structure was obtained. In the meantime,considering the geometrical nonlinearity and material nonlinearity, the whole process of theintegral structure stability was analyzed by using corresponding calculation scheme anditerative technology. And the load-displacement curve and the value of ultimate bearingcapacity were acquired. The development of rigidity and plasticity of component and failuremode under ultimate load was analyzed from imposing loads initially to the integral instability,and it turns out that the high-rise steel frame structure has better ultimate bearing capacity andductility.The main influence factors of the structure instability ware analyzed by setting up Severaladditional models, including the structure frame column section size, high wide ratio, differentlateral force resisting system, floor height, etc. The results showes that: the frame columnsection size has significant effect on ultimate bearing capacity of structure. Increasing thecolumn section size could improve the lateral stiffness of horizontal direction and reduce thelateral sway under the same level of loading, and the ultimate bearing capacity of structurewould increase significantly. As the high wide ratio increase, the ultimate bearing capacity ofstructure reduces gradually and the maximal displacement of structure under the limit loadincrease obviously. Setting the horizontal support could improve the ultimate bearing capacityand could control the lateral displacement of the structure, but setting the longitudinal supporthas little effect. Along with the increase of the floor height, the lateral rigidity reduces and thedisplacement increase under the same level of loading, and the ultimate bearing capacitysignificantly reduces. In the structure design, regarding construction safety and economicrequirement, the high wide ratio,component section size and floor height should be controlled in the reasonable scope to ensure structural integral stability,.This thesis provides some suggestions for the analysis of nonlinear integral stability insteel frame structure according to the problems and solutions encountered in the process of thecalculation, such as the loading value, solver setting and consideration of the grid precisiondivision. It has reference value in the analysis of nonlinear stability of similar structure.