Monitoring the Behavior of Bridges Using Digital Image Correlation

This dissertation investigates the use of Digital Image Correlation (DIC) – a non-destructive photographic technique that measures three-dimensional full-field strains and displacements based on photogrammetric triangulation and pattern recognition – to monitor the behavior of bridges. DIC can provide unparalleled data on bridge behavior, strength, and overall condition. A major challenge in using this technique for monitoring bridges is applying an appropriate pattern as conventional strategies (e.g., spray paint) are time-intensive and weather-dependent. To address this challenge, this dissertation qualifies a new patterning approach using pressure-activated adhesive tape. DIC is also validated for bridge monitoring by comparing DIC and strain gauge measurements directly for field monitoring, which has never been done in published literature. With an effective strategy developed for field monitoring of bridges using DIC, this dissertation uses DIC to understand the behavior of bridges from erection through in-service condition, and ultimately under repair. To understand the behavior of bridges during erection, DIC was used to measure the strain induced in the two edge girders, the end floor beam, and the supplemental longitudinal truss of the Governor Mario M. Cuomo Bridge due to cable anchoring and tie-down forces. To investigate in-service behavior, DIC was used to measure the behavior of steel girder bridges subjected to vehicular collision. Findings indicated that bridge rail participates in carrying live load, leading to a secondary study which used strain gauges to measure the behavior of undamaged steel and prestressed concrete girder bridges. The data was used to develop a validated finite element numerical modeling approach and perform parametric investigations, culminating in recommendations for bridge inspectors. To monitor the behavior of bridges under repair, DIC was used to investigate the repair of the fractured chord of the Delaware River Bridge, confirming that each step of the repair strategy was working as expected. The results of these different implementations clearly demonstrate that DIC can provide unprecedented data on the behavior of bridges in their different life stages: erection, in-service, and repair, as well as the great potential of DIC for engineering applications. This dissertation culminates in recommendations for effectively implementing DIC to monitoring bridges.