Wireless Sensor Network Deployments for Structural Identification in a Tied Arch Bridge

Structural identification of highway bridges, as well as individual components, through vibration-based measurement techniques may provide promising alternatives for in-service characterization of infrastructure health. This approach is particularly compelling since it links distributed dynamic response measurements to the global mechanics of the structure, whereas alternative nondestructive test methods provide very localized measures of structural change. In the present study, a tied arch bridge was instrumented using a high-rate wireless sensor network providing thecapability to measure real-time accelerations at 48 locations across the bridge. Referencebased testing was used to extract modal parameters for the full structure with high-resolution mode shapes constructed from hundreds of sampled locations. The spatial density was resolved fine enough that local response of plate modes in the rib arches were reconstructed, which may offer advantages for long-term diagnostic monitoring. Supplemental impulse-response testing was performed on the hanger cables of the bridge to extract estimates of the tension force in each cable through structural identification for further characterization of the structure. The estimation of cable force in tied arch bridge hangers presents a particular challenge since the cable slenderness ratios typically preclude use of approximation formulas. A summary of the applied experimental approach, extraction of a subset of modal parameters, and discussion of cable force estimation in the hangers is provided.

1. Brownjohn, J., A. De Stefano, Y.-L. Xu, H. Wenzel and A. Aktan. “Vibration-based monitoring of civil infrastructure: challenges and successes,” Journal of Civil Structural Health Monitoring, Vol. 1, pp. 79-95, 2011. 2. Friswell, M. and J. Mottershead. Finite Element Model Updating in Structural Dynamics, Dordrecht, Netherlands: Kluwer Academic Publishers, 1995. 3. Catbas, F., S. Ciloglu, O. Hasancebi, K. Grimmelsman and A. Aktan. “Limitations in Structural Identification of Large Constructed Structures,” Journal of Structural Engineering, Vol. 133, No. 8, pp. 1051-1066, 2007. 4. Hong, A., F. Ubertini and R. Betti. “Wind Analysis of a Suspension Bridge: Identification and Finite-Element Model Simulation,” Journal of Structural Engineering, Vol. 137, No. 1, pp. 133-142, 2011. 5. Peeters, B. “Continuous Monitoring of the Øresund Bridge: Data Acquisition and Operational Modal Analysis,” in Encyclopedia of Structural Health Monitoring, West Sussex, UK, John Wiley & Sons Ltd, 2006, pp. 2159- 2174, 2009. 6. Ahn, I.-S. and S. Chen. “Nonlinear Model-Based System Identification of Lead-Rubber Bearings,” Journal of Structural Engineering, Vol. 134, No. 2, pp. 318-328, 2008. 7. Weng, S.,Y. Xia, Y.-L. Xu and H.-P. Zhu. “Substructure based approach to finite element model updating,” Computers and Structures, Vol. 89, No. 9-10, pp. 772-782, 2011. 8. Whelan, M. “Design and Application of a Wireless Sensor Network for Vibration-Based Performance Assessment of a Tied Arch Bridge,” Structural Health Monitoring 2011: Condition-based Maintenance and Intelligent Structures, Lancaster, PA, DEStech Publications, Inc., pp. 709-716 2011. 9. Hietbrink, C. and M. Whelan. “System Identification of a Tied Arch Bridge using Reference-Based Wireless Sensor Networks,” in Smart Sensor Phenomena, Technology, Networks, and Systems Integration, San Diego, CA, 2012. Figure 7: Nonlinear least-squares fitting to the analytical solution for the transverse cable response. 383 10. Wenzel, H. and D. Pichler. Ambient Vibration Monitoring, West Sussex, UK: John Wiley & Sons, 2006. 11. Zui, H., T. Shinke and Y. Namita. “Practical Formulas for Estimation of Cable Tension by Vibration Method,” Journal of Structural Engineering, Vol. 122, no. 6, pp. 651-656, 1996. 12. Mehrabi, A. and S. Tonon. “Unified Finite Difference Formulation for Free Vibration of Cables,” Journal of Structural Engineering, Vol. 124, No. 11, pp. 1313-1322, 1998. 13. Ren, W., H. Liu and G. Chen.“Determination of cable tensions based on frequency differences,” International Journal for Computer-Aided Engineering and Software, Vol. 25, No. 2, pp. 172-189, 2008.
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