evaluation of existingtechniqueson structural health monitoringof bridges

the global higher transportation network operates about 2.5 million bridges all over the world. current bridge management systems rate them using various methodologies and approaches. based on studies in the us federal highway agency (fhwa), about 30% of bridges are rated as being deficient, with only a portion of these being deficient for structural reasons. for this reason, it is necessary to focus on bridges that definitely require structural health diagnosis, improvement and monitoring. structural health monitoring (shm) should be used in a preventive capacity before bridges become deficient. structural health monitoring is the implementation of a damage identification strategy to the civil engineering infrastructures. damage is defined as changes to the material and/or geometric properties of these systems, including changes to the boundary conditions and system connectivity. damage affects the current or future performance of such systems. structural health monitoring has several techniques, the methods are categorized based on the type of measured data used, and/or the technique used to identify the damage from the measured data. in this paper, first a review of the technical literature concerning the detection, location, and characterization of structural damage via techniques that examine changes in measured structural vibration response are investigated and then recent research and application activities on smart sensing, monitoring, and damage detection for bridges are briefly introduced.