NATURAL FREQUENCY IDENTIFICATION METHOD FOR A SUBSTRUCTURE IN BRIDGES AND VIADUCTS

Abstract

We have proposed a method to identify the natural frequency of a single structure from the data obtained by measuring the vibration of bridges and viaducts. In the method, the natural frequency of a single structure can be theoretically calculated by using the undamped natural frequencies and natural modes of the whole structure. The eigenvalue analysis was performed, and it was shown that the natural frequency of the single structure can be identified by the proposed method. Moreover, we evaluated the effect on the identification accuracy when the undamped natural frequencies of the whole structure contained errors, and it was found that the errors included in the high order natural modes had a large effect on the identification accuracy