ABSTRACT
Abstract This paper presents dynamic analysis of a thin and narrow turbo generator foundation on piles. The foundation dynamic stiffness used in the analysis varies with frequency, shear wave velocity and mode shape. Techniques for adopting suitable values of stiffness as a base case have been developed. Modal analysis was carried out using the base case. The results were used to investigate the required modifications to the base case to detect adverse or near resonance conditions. Modified stiffness values were used in the harmonic analysis to obtain the maximum amplitudes of vibration. The results are compared with those of rigid block models. It is shown that the Finite Element (FE) model predicts higher amplitudes of vibration due to flexural modes when compared to those from the rigid block model. Numerical predictions were validated using field tests and empirical methods. The approach used to account for variations in stiffness is applicable to non-piled foundations as well as to general FE analysis. Keywords: Dynamic analysis, finite elements, foundations, harmonic analysis, piles, shear wave velocity, turbogenerator, validation.
