Modeling of Traffic Excitation for System Identification of Bridge Structures

System input (traffic excitation) is difficult to measure, so system identification is often performed based only on the system output (bridge vibration responses) in long-term health monitoring of bridge structures. Traffic excitation is commonly modeled as spatially uncorrelated white noise to facilitate the identification of the bridge properties. A physical model of a stationary stream of vehicles (moving loads) arriving in accordance with a Poisson process, traversing an elastic beam, shows that the traffic excitation is spatially correlated. Employing the dynamic nodal loading approach, this spatial correlation results in a frequency-dependent excitation spectrum density matrix, and shifts the response spectra obtained from those excited by spatially uncorrelated white noise. It is shown that the application of system identification techniques based on the conventional excitation model may result in misleading structural properties. Hence, this study further proposes an output-only gray-box identification technique for bridge structures, in which knowledge about the nature of the traffic excitation, such as its spatial correlation, is implanted into an autoregressive-moving-average (ARMA) model. The identifiability of the ARMA model so constructed is assured and the feasibility of the proposed identification technique is demonstrated by a numerical example. With the proposed physics-based excitation model and the gray-box identification technique, information collected about traffic will directly contribute to improving the identification of structural structural properties.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/10939687
• Authors:
  • Chen, Yangbo
  • Feng, Maria Q
  • Tan, Chin-An
• Publication Date: 2006-1

Language

• English

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 57-66
• Serial:
  • Computer-Aided Civil and Infrastructure Engineering
  • Volume: 21
  • Issue Number: 1
  • Publisher: Blackwell Publishing
  • ISSN: 1093-9687
  • Serial URL: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1467-8667

Subject/Index Terms

• TRT Terms: Bridges; Excitation; Monitoring; Structural analysis; Traffic loads; Vibration
• Identifier Terms: ARMA (Auto-Regressive Moving Average model)
• Uncontrolled Terms: System identification
• Subject Areas: Bridges and other structures; Design; Freight Transportation; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 01020279
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 20 2006 7:28AM