ABSTRACT
The available structural damage identification methods, no matter whether work in the frequency or time domain, are mostly derived and studied using simple structure systems with small Degreeof-Freedoms (DOFs). However, in order to apply these damage identification methods to large and complex bridge structures, model simplification is necessary. This paper aims to develop a systematic procedure in establishing relatively simple models for the theoretical and numerical analysis of complicated bridge structures with large DOFs, such as cable-stayed bridges, by keeping the main static and dynamic characteristics of bridges. One of the main navigatin channels of Donghai bridge, Kezhushan Bridge, is used as an example in this study. The three dimensional (3D) finite element model of the bridge will first be established. Then, a two dimensional (2D) model will be obtained considering only vertical external excitations. Finally,
1 INTRODUCTION
A health monitoring system can obtain thorough information on the service condition of the bridges and provide basis for maintenance, repair and decision making, therefore, it becomes an important research topic in civil engineering field lately. One of the key technologies in structural health monitoring is the derivation of damage detection methods based on structural dynamic responses, where the crucial problem lies in the accurate and efficient identification of structural parameters. So far, there have been quite a number of data analysis methodologies available in the literature for system identification, such as Fourier based analysis methods (ex. Lin & Cai, 1995) and wavelet based approaches (ex. Naldi & Venini, 1997). As pointed by Huang et al (1998) that these methods have limitations when analyzing vibration data with nonlinear and nonstationary features, and therefore, Hilbert-Huang Spectral Analysis (HHSA) method was derived to process nonstationary signals.
