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Bridging the Gaps in Bridge Inspection Data

Pitt Civil Engineering Professor Investigates Bridge Monitoring Techniques

PITTSBURGH (Jan. 27, 2020) — The Commonwealth of Pennsylvania maintains over 25,000 bridges, and the average age of those bridges is 50 years, with a significant portion of them in poor condition. Making sure these bridges are safe is a vital job, but it’s also a dangerous one: Every year, an estimated average of 23  bridge inspectors of state Departments of Transportation (DOTs) lose their lives on the job, highlighting the need for an automated inspection method that is safe, accurate and efficient.

Amir Alavi, PhD, assistant professor of civil and environmental engineering at the University of Pittsburgh’s Swanson School of Engineering is undertaking a $200,000 project sponsored by the Impactful Resilient Infrastructure Science and Engineering (IRISE) Consortium at Pitt for work that will improve bridge assessment. IRISE is a public-private consortium focused on solving infrastructure durability problems.  Its members are Allegheny County, Golden Triangle Construction, Michael Baker International, the Pennsylvania Department of Transportation and the Pennsylvania Turnpike.

Alavi’s research will integrate three bridge assessment techniques: structural health monitoring (SHM), non-destructive evaluation (NDE) and visual inspection using unmanned aerial vehicles (UAVs), or drones. The study will establish a data fusion framework to identify the synergies among bridge degradation, remaining service life, and the SHM, NDE and UAV-collected data. 

Though using UAVs is an emerging civil infrastructure inspection method, it is presenting its own challenges. In the arena of bridge inspection, one of the unanswered questions is how DOTs can integrate the UAV systems with NDE techniques to additionally track deterioration at a higher temporal resolution, or the frequency at which data is collected, improving service-life models forecasting. 

“We have tons of systems collecting different type of information about the condition of the civil infrastructure systems and, in particular, our bridges. However, the problem is how to combine this information to give inspectors a more descriptive picture of the health status of the bridge,” says Alavi. “While one method can offer a better temporal information, the other may provide better spatial resolution, giving more visual detail but less frequently. One of our primary goals is to identify the level of unique information provided by each data modality and then fuse the data with various levels of spatial and temporal resolution to help bridge inspectors make better decisions more efficiently.”

To pursue this research, Alavi and his team will collaborate with the Center for Advanced Infrastructure and Transportation (CAIT) at Rutgers University, along with industry partner Wiss, Janney, Elstner (WJE) Inc. It will leverage the data collected by Rutgers’ Bridge Evaluation and Accelerated Structural Testing (BEAST) facility, the world’s first full-scale accelerated testing facility for bridges.

The team at the BEAST will monitor a multi-girder steel composite bridge that is 30 by 50 feet. They will expose the bridge to rapid-cycling environmental changes and extreme traffic loading to speed up the bridge’s deterioration, even undergoing simulated winter road maintenance treatments. Over the nine- to 12-month period, the bridge will go through the equivalent of 15 to 20 years of wear and tear. Alavi’s team will evaluate the resulting data to look for correlations between the SHM, NDE and UAV-collected data through the full-life cycle of bridge performance from the first day of service until to the point that the bridge will be functionally deficient and out of service. The team plans to build a layered heat map, stacking the data from each method to provide a more efficient picture of the bridge’s health and potential issues. 

The goal of the research is for PennDOT and the other IRISE public partner agencies to implement the framework, gaining valuable information that will inform how—and how often—bridge inspectors should use the various modalities to monitor bridge health.

“Understanding bridge condition is a critical aspect of infrastructure durability,” says Julie Vandenbossche, PhD, director of IRISE and William Kepler Whiteford professor of civil and environmental engineering at Pitt. “We’re pleased that Dr. Alavi’s work will improve the state-of-the practice in how those conditions are assessed.”

The team will address the reliability of the UAV-based assessment as compared to the commonly-used NDE methods.      

“The autonomous robotic inspection is the future of bridge inspection, and UAVs play a key role in this game. The problems we are facing for a wide application of UAVs are basically technological issues,” says Alavi. “There are solutions, it’s only a matter of time and research, and our research is a step in the right direction for an effective UAV implementation for bridge inspection in Pennsylvania and beyond.”

Author: Maggie Pavlick

Contact: Maggie Pavlick