Abstract
Models for foundation vibration analysis are reviewed in the paper. The models reviewed were examined their accuracy by vibration tests and earthquake observations of foundations and have been frequently used in dynamic design of structures. The models are the following four and classified to continuous and discrete ones.
Continuous model for surface footing.
Continuous model for deep foundation.
Discrete model for pile foundation.
Finite element model.
The characteristics of the models are as follows.
The ground of the first model is uniform and elastic.
Accuracy of the model significantly depends on how to select equivalent uniform elastic contants when analysing non-uniform real ground, which is a problem to be solbed in the model.
The second model has a tendency to give two or three times greater stiffness. A problem to be solved for the model is how to reduce accurately and reasonably the stiffness.
The third model has been most frequently used in practical design of structures with pile foundation for its small number of unknowns and low costs of computer. But accuracy of the model greatly depends on damping evaluation of ground, whose methods are not yet established.
The fourth model is versatile and usually gives fairly good accuracy even for non-uniform ground. But because of great number of unknowns, the model requires great costs of computer and application of the model is restricted to designs of important and high-class structures.
