Earthquake wave-soil-structure interaction analysis of tall buildings

Date

2010-06-14T18:41:07Z

Authors

Yao, Ming Ming

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Abstract

Earthquakes cause damages to structures and result in great human casualties and economic loss. A fraction of the kinetic energy released from earthquakes is transferred into buildings through soils. The investigation on the mechanism of the energy transferring from soils to buildings during earthquakes is critical for the design of earthquake resistant structures and for upgrading existing structures. In order to understand this phenomena well, a wave-soil-structure interaction analysis is presented. The earthquake wave-soil-structure interaction analysis of tall buildings is the main focus of this research. There are two methods available for modeling the soil-structure interaction (SSI): the direct method and substructure method. The direct method is used for modeling the soil and a tall building together. However, the substructure method is adopted to treat the unbounded soil and the tall building separately. The unbounded soil is modeled by using the Scaled Boundary Finite-Element Method (SBFEM), an infinitesimal finite-element cell method, which naturally satisfies the radiation condition for the wave propagation problem. The tall building is modeled using the standard Finite Element Method (FEM). The SBFEM results in fewer degrees of freedom of the soil than the direct method by only modeling the interface between the soil and building. The SBFEM is implemented into a 3-Dimensional Dynamic Soil-Structure Interaction Analysis program (DSSIA-3D) in this study and is used for investigating the response of tall buildings in both the time domain and frequency domain. Three different parametric studies are carried out for buildings subjected to external harmonic loadings and earthquake loadings. The peak displacement along the height of the building is obtained in the time domain analysis. The coupling between the building’s height, hysteretic damping ratio, soil dynamics and soil-structure interaction effect is investigated. Further, the coupling between the structure configuration and the asymmetrical loadings are studied. The findings suggest that the symmetrical building has a higher earthquake resistance capacity than the asymmetrical buildings. The results are compared with building codes, field measurements and other numerical methods. These numerical techniques can be applied to study other structures, such as TV towers, nuclear power plants and dams.

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Keywords

soil-structure interaction, Tall buildings, Scaled Boundary Finite Element Method, SBFEM

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