ABSTRACT
In this paper, the natural frequencies are selected as the indicators of damages of bridge foundations, which are mainly influenced by the rigidities of foundation bodies and the subsoil properties. The quantitative influences of the two factors are analyzed by some numerical examples in which damage scenarios are simulated by degrading either the body rigidity coefficients or the subsoil spring coefficients, and some laws are obtained. The concept of soundness index is put forward and the index is used to evaluate the damages of bridge foundations. For the familiar spread foundations, pile foundations and caisson foundations in railway bridges, according to the provisions on the safety coefficient of foundation design in Chinese Code for Bridge Foundation Design, the safety limitation values of soundness indexes are determined on the basis of numerical examples and real engineering disaster cases.
