Exploration of video-based structural health monitoring techniques.

PDFTech ReportCAIT-UTC-038DTRT12-G-UTC16Structural health monitoringVibrationSensorsDigital videoLaboratory testsUnited StatesRutgers University. Center for Advanced Infrastructure & TransportationShariati, AliSchumacher, ThomasRamanna, NakulUniversity of Delaware. Center for Innovative Bridge EngineeringRutgers UniversityDelaware. Dept. of TransportationUnited States. Federal Highway AdministrationUS Transportation CollectionStructural health monitoring (SHM) has become a viable tool to provide owners with objective data for maintenance and repair. Traditionally, discrete contact sensors such as strain gages or accelerometers have been usedfor SHM. However, distributed remote sensors could be advantageous since they don\ue2\u20ac\u2122t require cabling and cancover an area rather than a limited number of discrete points. Digital image correlation (DIC) has been usedsuccessfully but has disadvantages in terms of complexity and computational costs when applied to vides. In thisresearch project, we investigated and proposed a di\uef\uac\u20acerent approach. The basic concept is that small changes inthe intensity value of a monitored pixel with \uef\uac?xed (or Eulerian) coordinates caused by the vibration of structurescan be captured, even if it is not invisible to the naked eye. In this research report, we explain the basic conceptand mathematical theory for our proposed so-called virtual visual sensors (VVS), we present a set of laboratoryexperiments to demonstrate the accuracy of the approach, and provide two practical monitoring examples ofin-services bridges. Finally, we discuss future work to improve the current methodology