Experimental and Analytical Study of Dynamic Behavior of a Bridge

Abstract

This paper presents and discusses the dynamic behavior of two bridge decks. The experimental tests were performed to explain the dynamic performance of one of them: its vertical displacements and accelerations are appreciably greater than those of every other deck in the same bridge, despite similar geometrical and mechanical properties. The experimental data were used to identify the modal parameters of the decks, which have close frequencies. A simultaneous analysis using a two-degrees of freedom (DOF) model, which exhibits dynamic characteristics similar to the first modes of the deck, was carried out. It showed that, when coupled frequencies occur, the sensitivity of the response to the properties of both the system and the excitation is very high, which may explain the difference in the displacements observed.