Application of Filtering Techniques to Indirect Measurement of Bridge Frequencies
Date Issued
2011
Date
2011
Author(s)
Li, Yu-Chien
Abstract
Bridge frequency is an essential dynamic parameter in bridge engineering. It is one of the parameters that have been used in the areas of structural damage detection, structural health monitoring and structural model updating.
Traditionally, the bridge frequencies are measured from the dynamic response of a bridge via the vibration sensors directly mounted on the bridge. Such an approach is referred to as the direct approach.
In recent years, another concept is proposed for measuring the bridge frequencies from the dynamic response recorded of a vehicle during its passage over the bridge of concern. Such an approach is called the indirect approach.
Compared with the direct approach, the indirect approach has the advantages of being more economic, fast, and movable. Whenever a natural disaster (e.g., an earthquake) occurs, this approach can quickly provide the information of bridge frequencies to field engineers for preliminary safety assessment.
The objective of this study is to investigate the effect of road surface roughness from a theoretical point of view via numerical simulation, to refine the indirect approach for extracting the bridge frequencies by filtering techniques and Stochastic Subspace Identification technique, and to investigate the feasibility of extracting bridge mode shapes from the dynamic responses of a vehicle via Hilbert transform. Furthermore, several signal filtering techniques are adopted in this study: the traditional band-pass filter, Singular Spectrum Analysis and band pass-filter based Singular Spectrum Analysis. Various numerical examples will be conducted using each technique with the conclusions drawn.
Subjects
bridge frequencies
indirect approach for measuring the bridge frequencies
road surface roughness
Hilbert transform
Singular Spectrum Analysis
Stochastic Subspace Identification technique
Type
thesis
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