Damage Progression of Highway Bridges and Operational Vibration-Waveforms

"The dynamic response of civil structures has long been utilized in damage detection. Techniques such as vibration-based damage identification, usually focused on experimentally determining modal parameters, have shown promising applications in detecting damage on bridges. A major drawback of most current damage-detection techniques, including the current video-based approach using drones, is in their incapability to explain the cause or the condition under which certain types of damage occur at different locations on the bridge. In this work, a nondestructive vibration-based approach, operational response and waveform analysis (ORWA), will be used to determine a cause and possible prevention solutions to the local damage occurring on bridges. In ORWA, damage on a bridge is correlated to the structural motions that are generated by the operational crossing traffic. By identifying the type and speed of vehicles that can put the bridge in deformation modes that can cause determinantal damage when they cross the bridge, new mitigation, maintenance, and (potentially) traffic rules can be developed to reduce these effects. In a previous work supported by IDOT [1], the initial idea of ORWA was presented and tested on a single-span highway bridge. A modified form of ORWA was developed [2] and used finite element analysis to correlate traffic vibration waveforms with the modal response of the bridge. In this work, ORWA will be enhanced to include a camera-based system that would be integrated and synched with the vibration waveform measurements. The newly developed ORWA will be tested and validated on two bridges in Iowa. "

Bridges in Iowa and across the US are old, getting older, and deteriorating with time. While many methodologies are developed to capture damage on bridges, there is no current methodology that provide reasons on why damage is happening and what are the best ways to mitigate and reduce that damage. This work presents a new scheme to identifying the root cause of the damage and providing a solution/remedy to the problem.

Safety, Equity, Transformation, and Organizational Excellence.

This project will have broader impacts on many fronts. First, it will be the first system that can be used to identify the cause and, potentially, the location of damage on the bridge. Second, because the system is portable, low-cost, and lightweight, it can be used by different bridge owners across the world, especially in rural areas and in communities with limited income. Third, the proposed system can potentially be used on different types of structures other than bridges, such as wind turbines and power transmission towers.