Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
Super high-rise, special-shaped steel structure or steel-mixed structure is not only very complex in the structural use stage, but also the deformation and stress of the structure in the construction process is particularly complex. The project is a steel frame-core tube structure with special shape, and there are many oblique truss structures, whose top is strongly connected with the giant truss or core tube on the opposite side through horizontal members, forming a “giant structure”. Before and after the closure of the whole structure, the stress forms of the main components of the steel truss are very different. Therefore, consider the vertical members and the corresponding floor in the conventional sequence of the construction layer by layer, while the diagonal steel truss needs to be assembled in place, the overall structure is formed and then remove the temporary support, and the gravity load is applied. In addition, due to the large difference in vertical stiffness between the core cylinder and the truss, the vertical deformation difference between the two causes greater internal forces in the members connected to the core cylinder. For this reason, after referring to the treatment of the super high-rise mid-boom truss, the design adopts the means of “put”, that is, the members adjacent to the core tube adopt the practice of post-solid connection and post-installation, in order to reduce the adverse impact of vertical deformation. In order to reduce the initial deformation and internal force of the structure generated in the construction process and realize the above requirements of “release”, according to the force needs, combined with the feasibility and economy of the construction, two kinds of construction assembly schemes are designed and drawn up, and the finite element program SAP 2000 is used for calculation and comparison. The precise simulation scheme refers to that the deformation and stress in the process of component assembly are fully considered in strict accordance with the construction sequence, and are accumulated into the final internal force calculation and deformation control. Simplified simulation means that most of the components are formed in the calculation model at one time, and the analysis focuses on the influence of post-installation and post-fixation of some components on the overall structure and related components. The main difference between the two schemes is that scheme A considers that the newly assembled steel truss has been cantilevered for a period of time before the construction is completed, while Scheme B does not consider the impact of this part.
Taking a typical steel truss as an example, the calculation results of internal force and joint displacement of the two schemes are analyzed and compared. Due to the particularity of the construction scheme of the project, the calculation model and parameters are specially treated in the design to realize the accurate simulation of some steps in the construction scheme.
The results show that there is no significant difference in the internal force and deformation of the two simulation schemes in the final state, the deformation form and internal force distribution are similar, and the change range of internal force in the final state of most members is less than 3%. According to the analysis results, a simplified simulation scheme is selected to improve the analysis efficiency under the premise of ensuring the calculation accuracy.
