Mid-America Transportation Center


Date of this Version


Document Type



Report # MATC-UI: 472 Final Report 25-1121-0001-472


2012 Copyright of Mid-America Transportation Center


The goal of this study was to evaluate the performance of Fiber Bragg Grating (FBG) sensors able to detect impacts with different frequencies on a bridge pier. The FBG technology was evaluated under controlled conditions in a laboratory flume set-up to mimic the flow, sediment, and design characteristics of a pier structure. The system was calibrated using site-specific properties to relate strain to a known magnitude force for different bridge pier designs, different scour depths, and structural impacts. The FBGs proved a reliable measure of strain and displacement for key components of bridge structures, such as piers, during varying flow magnitudes. Additionally, the FBGs were used to assess the impacts of different flow-altering countermeasures on the displacement of a bridge structure. Sacrificial piers that were approximately three pier diameters from the bridge proved to minimize the strain at the top end of the pier significantly. Practical guidelines were developed on how the FBGs can be used to provide real-time state awareness information for making decisions on down time, repair cost, and functionality of bridges. The research will pave the way for inexpensive, bridge automated monitoring, while providing an open framework to expedite the development of similar systems for other critical infrastructure, such as roads, highways, dams, levees, and prevent catastrophic events such as the Minnesota bridge collapse in 2007.