a frequency domain dynamic analysis is needed to obtain the response of structures constructed on a system of base isolators on flexible soil when subjected to earthquake ground motion. in such systems, the lateral stiffness of the base isolators is so small, compared to the structural stiffness, that in an earthquake attack the fundamental vibration mode dominates the response. with this in mi...

The effects of a heavy travelling load on the soil medium and on the adjacent structures were studied. Five soil profiles were analyzed, three from sites in Southern California and two from well documented sites in Europe. It was found that the material damping in the soil layers does not affect attenuation, but rather radiation damping is the most significant. Four of the Five soil profiles st...

A new bridge that will replace the existing Woodrow Wilson Bridge is under construction over the Potomac River in Washington, DC. The river piers are supported on cylindrical steel piles of 72, 54 and 48 inches in diameter. The longest piles (at the bascule piers) are approximately 200 ft long. Outside the river, nearly all piers are supported on 24-inch square prestressed concrete piles. Altho...

The stiffness and damping of pile foundations are proposed, which vary with the ratio of shear modulus Gi / Go to indicate the nonlinear properties of soil. The range of Gi / Go is defined with different vibration intensities for applications, and a computer program DYNAN is available based on the boundary zone model with non-reflective interface. Two engineering cases are studied to illustrate...

Values of site factors in numerical simulation can have profound effects on the calculation accuracy. In order to fully understand the performance of rigid-pile composite foundation in tall buildings, this article set up an overall FEA model of a 25-storey frame-tube structure by considering the interaction of superstructure, foundation and ground. Thereafter, a detailed parametric study was pe...

Tuned Mass Dampers (TMDs) can represent an attracting solution to mitigate vibrations of a structure under seismic excitation, but their effectiveness be considerably altered by the dynamic interaction with foundation soil. The available design criteria for TMDs do not account these effects and therefore lead non-optimised structural performance. In this paper investigation on TMD whole soil-st...

Field evidence from recent earthquakes has shown that structures can be designed to survive major surface dislocations. This paper: (i) Describes three different finite element (FE) methods of analysis, that were developed to simulate dip slip fault rupture propagation through soil and its interaction with foundation–structure systems; (ii) Validates the developed FE methodologies against centr...