FEA On Interaction Of Frame Structure-raft-subsoil

The vigorous development of modern construction to promote the developmentof the theory of civil engineering. The application of the upper structure, raftfoundation and foundation interaction method to guide now has become a hot issuein the field of civil engineering research. The three are influenced each other. Theynot only meet the static equilibrium, but also meet the deformation coordination Theconventional design method which is widely adopted by the civil engineering circlesneglect the deformation compatibility condition. So the design of the upper structureis not safe and the raft foundation is not economy enough.This paper first introduces the upper structure, raft foundation and foundationof the mechanism of influence each other and their respective analysis of the model.Then introduces the finite element software ANSYS and the choice of modelelements. Finite element analysis as a practical numerical analysis method, caneffectively simulate the actual engineering. The theory of finite element analysissoftware is based on the finite element theory, the finite element theory, to ensurethat the model is accurate and reasonable. According to the actual engineering toestablish pure frame structure, raft foundation and foundation of whole modelspace,the interaction under the vertical load is analyzed. The following work in thethesis are as follows:(1) To introduce the interaction mechanism and the selection of model(2) how to apply ANSYS to influence each other under the interaction of theupper structure, raft foundation and foundation and to realize the force equilibriumand deformation coordination.(3) Comparing the differences of conventional design method and combinationmethod of internal force of upper structure and raft foundation settlement. Afterconsidering the interaction, the internal force of corner column and side columnincreases obviously, and the load range of corner column is greater than the loadrange of side column. At the same time, the internal force of the core tube and theinterior column decrease obviously. The loading effect of superstructure componentis quite obvious in the lower floors. In upper floors, the loading effect and theunloading effect are tend to be decrescent. Raft settlement is reduced significantly,and differential settlement is also reduced. (4) When the joint action of the other parameters constant, changing only theupper part of the structural rigidity, stiffness increases with frame column axial forceincreases, increasing raft foundation settlement, differential settlement decreases.Changed only when the other parameters constant raft thickness, with increasingthickness, corner posts and side column axial force is reduced, the column axialforce increases, the columns moment decreases, while the raft foundation settlementand differential settlement decreases. Changed only when the other parametersconstant foundation stiffness, with stiffness increases, will help reduce the stress ofthe upper structure, while the value of the raft foundation settlement and differentialsettlement decreases, but the deformation and stress effects on a small raft.The calculation results which considered the interaction effect of finite elementanalysis obtained more tally with the actual situation. Optimizing suggestions toengineering designs and supplemental revising proposes to current foundationdesigns.