Vibration of hammer foundations

Abstract Hammer foundations are often deeply embedded and highly damped. Yet, in the prediction of vibration amplitudes, damping is usually neglected. In this paper, two methods are proposed which make it possible to incorporate damping in the analysis. One method, suitable for hand calculations, is based on an energy consideration and the other, suitable for computer analysis, utilizes the notions of the complex eigenvalue problem. It is shown that damping derived from soil may reduce foundation amplitudes very significantly, e.g. 50%, particularly for large, embedded foundations. Methods for the evaluation of foundation stiffness and damping which are needed in the analysis are outlined.

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