Effects of Temperature on Bridge Dynamic Properties

Structural health monitoring (SHM) using ambient vibration has become a valuable tool in evaluating and assessing the condition of civil structures. For bridge structures, a vibration-based SHM system uses the dynamic response of a bridge to measure modal parameters. A change in a structure’s modal parameters can indicate a physical change in the system, such as damage or a boundary condition change. These same modal parameters are sensitive to environmental factors, mainly temperature. Statistical models have been utilized to filter out modal parameter changes influenced by temperature and those caused by physical changes. Statistical models also help describe the relationship between modal parameters and environmental conditions. For this research, a lab specimen, I-girder, concrete box-girder, and steel plate girder bridges were studied. A SHM system was installed on these structures and vibration and temperature data were collected. This data was used to understand how the bridge’s natural frequencies typically change due to temperature.