Nonlinear Analysis Of Interaction Of High-Rise Building Superstructure-Piled Raft Foundation-Soil

High-rise building is the product of development of premodern economy and advancement of science. The main characters of high-rise building are big number of plies, tall flexible, high load, and good seismic -resistant ability. The requirement of foundation design and construction method is higher and more strict because of these characters. Generally speaking, the foudational form, designing theory, and construction method that are consistently used in multi-story building can not be simply used in high-rise building, so those according with high-rise building have to be chosen. The impact of interaction of superstructure, foundation and soil is not considered in traditional methods, and the computation result is different from practical situation. These irrational phenomenon especially occur in high-rise building. The structure, foundation and ground-base are an organic whole, which are associated with and affected by one another. The influences of interaction can't be ignored in the structural design of building.The practical engineering project-Shaanxi province post telecom net-managing building is analyzed as the study object in this paper. Based on the foundational theory on interact of high-rise building, piled raft foundation and ground base, the homologous model is established, and the stationary analysis and dynamic characteristics of interaction structure is studied. The above works are completed using FEM programme, ANSYS, and the grouped piles foundation is considered as equivalent composite material. The content and conclusions of this paper is as follow:(1) The model is establish by the equivalent composite model, which considers pile-soilsystem of grouped piles foundation as transversely isotropic body, and part of elements of the equivalent composite model is reduced using Guyan reduction. As a result, the total number of element and node of the whole model are decreased. These work provides an efficiently way on analyzing stationary complicated model made up of elastic and nonlinear composite material.(2) The structure is established according to the construction documents, and the construction procedure is simulated and compared base on three different kinds of ground base modal that is rigid elastic and plastic. Then the changing rule of structure's internal force of superstructure, foundation settlement, internal force of raft and background reaction etc. is gained.(3) In this paper the compact of other factors, such as Raft Thickness and elastic ratio of soil layer etc, on internal force of foundation settlement, internal force of raft and background reaction of the structure.(4) The natural period and mode of the structure was gainsed By analyzing dynamic characteristics of the considered interaction structure using the Component mode synthesis method (CMS), It has found that compared with the structure of rigid ground base, the natural period of the structure becomes longer and the model of it changes as a result of the ground base's limited Stiffness. Compared with the whole FEM model, the computation time is reduced and the analyzing efficient is improved while the computation precision is preserved using CMS.