| Soil-structure interaction (SSI) is an important subject with great theoretical significance and application value of engineering. Though the significant progresses on the respects of theory and application for past forty years have been made, there are still important problems to be solved. Developing an effective and practical analysis method considering SSI,and knowing the effects on seismic response considering SSI of structures are two of these problems. In this paper, on the basis of the current development of SSI research at home and abroad, the reinforced concrete high-rise buildings as a research object, the study on seismic response analysis considering SSI of high-rise buildings is conducted. Some practical analysis measures are provided for seismic SSI response analysis of important individual high-rise buildings or general high-rise buildings considering SSI. The basis is provided for understanding the effects on seismic response of high-rise buildings considering SSI and seismic design method.In this paper, soils and structure as an integrated system using plan SSI model, which can simulate the mechanical characteristics of the upper structure and the lower foundation well, a practical method for seismic response analysis considering SSI of high-rise buildings is proposed. In this integral analysis method, the plan frame-shear wall (tube) cooperation model is used in the upper structure. A soil mass with height H and width B in-plane, and thickness t out-plane is used to simulate the foundation soils. Duncan-Chang model of soils is used in static analysis; equivalent linearization model of soils is used in dynamic analysis. According to the shape and stiffness of basements, the flexible, rigid and pile foundation are simulated by beam element, rigid block or plate element respectively. In order to realize this method in personal computer, the redevelopment of the finite element analysis software MSC.Marc is done, which Duncan-Chang model for static analysis and equivalent linearization model for dynamic analysis of multi-layer soils are added, and two examples are calculated to verify the reliability of the redevelopment. Thus software MSC.Marc becomes an ideal analysis tool for this integral analysis method. This method can be used for the seismic response analysis considering SSI of important individual high-rise buildings in details.Ten typical reinforced concrete high-rise buildings with different heights, IVdifferent structural types and different site conditions are selected, which are located in thick and deep foundations soils. Using the integral analysis method of seismic response analysis considering SSI, the bedrock wave, ground motion wave and equivalent seismic input wave are compared and analyzed, and the natural vibration characteristics and seismic response of soil-structure system considering SSI are compared and analyzed with those of structure system not considering SSI. The seismic SSI effects on the response of high-rise buildings located in thick and deep foundation soils are analyzed and studied in details. Through the comprehensive analysis of effects on the response considering SSI, some practical conclusions and relationships are obtained on some respects of ground motion input, natural vibration characteristic, SSI effect factor, and seismic response. On the base of these conclusions and relationships, a simplified assessment method of seismic response analysis considering SSI of high-rise buildings is obtained, regarding the first period coefficient of structure and soils -αT as an index. In this method, it is not necessary to conduct the complex and time-consuming SSI analysis of high-rise buildings. Using the results of simple and time-saving structure or soil response analysis, the response of SSI system can be assessed. This method can be used for the primary assessment of seismic response analysis considering SSI of high-rise buildings.Taking the calculation results of ten typical high-rise buildings using the integral analysis method as a standard. The plan frame-shear wall (tube) cooperation model is still used to simulate the upper structure in the integral analysis method. Refering to the"Code for design of dynamic machine foundation (GB50040-96)", the two-layer simplified model of foundation is proposed. By comparing with the standard results of ten typical high-rise buildings, the two-layer model is gradually revised on respects of foundation mass, degree of freedom of foundation model, shear stiffness and damping ratio of soils. The mass of foundation is improved from the mass between basement and bedrock to the foundation mass of the integral analysis method, the freedom of foundation is improved from two-degree to multi-degree, the shear stiffness of each layer is given also, the shear module G of soils is suggested to take as 0.5 times Gmax and the damping ratio is taken as 15%. A corrected multi-layer model of foundation is proposed, and a simplified analysis method of high-rise buildings considering SSI is proposed. It can be seen by comparing the results of the multi-layer method and the integral analysis method that, the natural vibration period and the maximum acceleration peak value of roof are improved more obviously than those of the old two-layer simplified method, and the acceleration response spectra of roof are improved more reasonably, especially the periods corresponding to peak values in long period range the periods are similar to those of the integral analysis method. So it can be seen that this simplified method can be used for the seismic response analysis considering SSI of general high-rise buildings, or the primary seismic response analysis considering SSI of important high-rise buildings. In addition, the simplified model of foundation in this simplified method can be also extended to use on the foundation and soil-structure interaction of other types of buildings and structural engineering.
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