Installation of Thermocouples, and Analysis of Temperature Data from the 21st South Bridge

2018Final Report, 04/01/16 to 08/31/17PDFTech ReportCAIT-UTC-NC33DTRT13-G-UTC28Data analysisField testsFrequency (Electromagnetism)Highway bridgesInstallationStructural health monitoringTemperature measurementThermocouplesmodal analysisbridge instrumentationdamage detectiontemperatureambient vibrationbridge field testingUtahUnited StatesUtah State UniversityNichols, Gilbert AHalling, Marvin W.Barr, Paul J.Utah State UniversityRutgers University. Center for Advanced Infrastructure and TransportationUnited States. Department of Transportation. Research and Innovative Technology AdministrationUS Transportation CollectionStructural Health monitoring is to determine the condition of a bridge based on instrument measurements. The C-846 Bridge in Salt Lake City has such instrumentation. The bridge is located in Salt Lake City at about 2100 South and Interstate 15. This bridge has two kinds of instruments on it: accelerometers and thermocouples. The accelerometers measure the vibrations of the bridge. The accelerometers have been recording data on the bridge since 2001. The thermocouples, which measure temperature, were added as part of this installation in April 2016. In light of recent research, damage may be detected from measuring the change in the natural frequency of a bridge, which can be obtained by manipulating the accelerometer data. However, the natural frequencies of a bridge change due to environmental effects, especially temperature. Temperature effects must be accounted for in order to better understand the damage. The purpose of this research is not to detect damage. The bridge that is being monitored does not have any damage. The purpose of this study is to show how the dynamic properties of the C-846 Bridge in South Salt Lake City correlate with temperature. Additionally, several frequencies including the fundamental frequency of the bridge are identified. It was found that the natural frequencies of the bridge increase with a decrease in temperature, and that the fundamental frequency of the bridge is 1.15 Hz.93