Structural Health Monitoring Studies of the Alamosa Canyon and I-40 Bridges
From 1994 to 1997 internal research grants from Los Alamos National Laboratory's Laboratory Direct Research and Development (LDRD) office were used to fund an effort aimed at studying global vibration-based damage detection methods. To support this work, several field tests of the Alamosa Canyon Bridge have been performed to study various aspects of applying vibration-based damage detection methods to a real world in situ structure. This report summarizes the data that has been collected from the various vibration tests performed on the Alamosa Canyon Bridge, analyses of these data, and the results that have been obtained. Initially, it was the investigators' intent to introduce various types of damage into this bridge and study several vibration-based damage detection methods. The feasibility of continuously monitoring such a structure for the onset of damage was also going to be studied. However, the restrictions that the damage must be relatively benign or repairable made it difficult to take the damage identification portion of the study to completion. Subsequently, this study focused on quantifying the variability in identified modal parameters caused by sources other than damage. These sources include variability in testing procedures, variability in test conditions, and environmental variability. These variabilities must be understood and their influence on identified modal properties quantified before vibration-based damage detection can be applied with unambiguous results. Quantifying the variability in the identified modal parameters led to the development of statistical analysis procedures that can be applied to the experimental modal analysis results. It is the authors' opinion that these statistical analysis procedures represent one of the major contributions of these studies to the vibration-based damage detection field. Another significant contribution that came from this portion of the study was the extension of a strain-energy-based damage detection method originally developed for structures that exhibit beam-bending response to structures that exhibit plate-like bending or bending in two directions. In addition, based on lessons learned from the Alamosa Canyon Bridge test, data from the I-40 Bridge tests have been re-analyzed using the statistical analysis procedures developed as part of this study. The application of these statistical procedures to the I-40 Bridge test results gives particular insight into how statistical analysis can be used to enhance the vibration-based damage detection process.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 766805
- Report Number(s):
- LA-13635-MS; TRN: AH200036%%36
- Resource Relation:
- Other Information: PBD: 1 Jul 2000
- Country of Publication:
- United States
- Language:
- English
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