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In this paper, the influence of soil-structure interaction(SSI) effects on maximum displacement response of low-medium rise reinforced concrete building with relatively high strength are studied. A practical procedure with a simplified model including nonlinear SSI effects to predict maximum displacement response is proposed. Shear force-displacement relation and damping factor including SSI effects are obtained by using maximum displacements response of simplified model and surface ground layer due to strong ground motions. The maximum response estimation due to strong earthquake motions is demonstrated using example models of reinforced concrete 5-story building and surface ground deposit. The validity of proposed procedure is examined in comparison with the results of nonlinear response analysis using 2-dimentional FEM model.

Performance-based seismic design of structures has been widely recognized as useful design concept, in which required performance such as safety, serviceability and others are explicitly described, and the required level of the performance are quantitatively specified. The required level has often been expressed in terms of return periods of earthquake ground motion intensities such as PGA or spectral acceleration, all of which do not fully represent ground motion time histories. Recent advancements on theoretical as well as semi-empirical fault models in engineering seismology should be incorporated to meet the required performance levels of structures. Therefore, this paper proposes a new reliability- based methodology for determination of source parameters of the fault model which correspond to the return period specified by design requirement.

Large amount of ground motion records has been accumulated at stations of existing K-NET, KiK-net and other observation network systems throughout Japan. They have been utilized in various ways such as deeper understanding of earthquake source and characteristics and wave propagation characteristics, establishment of more precise ground motion attenuation relationships, application to early warning systems, etc. The past attenuation relationships for PGA, PGV, or other intensity measures of ground motion have been established through regression analyses of observed records. They can be easily used for wide range of applications. Shortcomings of the traditional attenuation relationships, however, can only predict the attenuation property of a single intensity measures, not the whole attenuation property of ground motions. It is presented in this paper that a new and easy-to-use selection method of records from ample observed earthquake records inventory (Data-base) is proposed instead of establishing another attenuation relationship.

Ground motion attenuation relationships for spectral acceleration have been developed in Japan. Although these prediction models can usually provide a mean value and a standard deviation for each specified period, they do not characterize covariance property of spectral acceleration between two different periods. This leads to less accurate prediction of response of structural systems such as multi-degree-of-freedom systems and nonlinear systems. Some studies have paid attention to this shortcoming and tried to model the correlation of spectral accelerations by statistical method based on the small number of records. In the present paper, a large amount of ground motion records, which were observed from the recent earthquakes by K-NET and KiK-NET, were used in the covariance analysis. The covariance structure of two spectral values were investigated through principal component analysis. The covariance characteristics were fully investigated by examining the effects of the different source, path and soil conditions. And response spectra are simulated using principal components as an application of principal component analysis.