Seismic Response Analysis Of Soil-Adjacent Structures Dynamic Interaction

With the shortage of land resources, the limit of block conditions and the increasing of the difficulty and cost of the exploiting land, the major product forms of the real estate development are dense high-rise buildings in the city center. However, the rigid ground assumption has been used for earthquake response analysis in the city seismic design and only single structure is considered in the model. It is reasonable only when foundation stiffness is much more than superstructure stiffness. Nevertheless, there is no building with the single site condition, especially the buildings in the city center. Every building is more or less interfered by other buildings around it. The seismic response of actual structures is quite different from that of setting in the single site condition, and this difference may cause adverse effect in the buildings. Therefore, it is necessary to consider the influence of the surrounding environment and the site condition, when structures are analyzed with earthquake. Soil-Structure Interaction is just a seismic design method that can solve above problems.Although research results about SSI are abundant at present, they do not consider the influence of the surrounding structures. This paper proposes a method considering the effect of the adjacent structure on the basis of existing theoretical results, and deduces the impedance of subsoil. Then it analyzes the factors which can affect the impedance of subsoil and the dynamic response of the structure. At last the parametric analysis is presented for the Soil-Adjacent Structure Interaction. The law of the effect is found from the parametric analysis. The major research contents and innovation in this paper is that:(1) Establish the dynamic equilibrium equation which considers existence of the adjacent structure. This equation also considers the horizontal movement of the two superstructures and foundations, turning motion of the two foundations and phase difference of the two moving systems.(2) Deduce the foundation static stiffness of the subsoil on the basis of analytical solution of the Mindlin in elastic half space. Then each part of stiffness in the dynamic analysis is deduced according to the static stiffness.(3)Use the analysis model proposed in this paper to calculate the dynamic response of actual structures. And explore the influence of the existence of adjacent structure.(4)Make parametric analysis for the Soil-Adjacent Structure Interaction. The parametric includes the clear distance of the two foundations, ratio of two foundation sides, the ratio of mass of the two superstructures, the ratio of the two foundations, characteristics of the soil. According to the results of analysis, get the influence law of those parametric.