09-10-2014, 02:53 PM
A stochastic approach has been proposed for the seismic analysis of linear, multiply-supported secondary systems. The transfer function for the desired response quantity has been formulated by directly using tile fixed-base modes of the primary and secondary systems. This, thus, does not involve the determination of the combined system properties. The approach is applicable to the secondary systems with various mass ratios and configurations. Through a few example primary-secondary systems, tile transfer functions obtained from the proposed formulation have been shown to be in perfect agreement with those based on all exact formulation. This formulation has been extended to the flexible-base primary-secondary systems by assuming the soil medium to be a uniformly visco-elastic half-space. Using this, a study on the effects of soilstructure interaction has been carried out, and it has been shown that, the secondary system responses may increases due to soil-structure interaction effects for medium to stiff soil conditions.