Abstract

The present paper presents the results of the numerical study designed to investigate the soil-structure flexibility effects on modal parameters (i.e. fundamental frequencies) and time-history analysis response (represented by the top relative displacements) of a 46.8 m high steel lattice tower subjected to a number of ground motions including also one mining tremor. In addition to the fixed-base condition, three different soil types (i.e. dense soil, stiff soil, and soft soil) were considered in this investigation. Site conditions were characterized by their average effective profile velocities, Poisson’s ratios, and finally mass densities. Soil-foundation flexibility was introduced using the spring-based approach, utilizing foundation springs and dashpots. The first step was to investigate the influence of different base conditions on modal parameters of the steel lattice tower. In the final part of the current study time-history analysis was performed using different two-component ground motion records (in two horizontal, mutually perpendicular directions). The results obtained indicate that modal parameters and dynamic response of the structure may be considerably affected by the soil-structure interaction effects. Therefore, the present paper confirms the necessity of utilizing soil-flexibility into numerical research.

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