University of Vermont

UVM TRC features Hernandez Research on Bridge Monitoring

Eric HernandezThe Vermont Agency of Transportation (VTrans) in collaboration the University of Vermont Transportation Research Center (TRC) has initiated a collaborative research project with Dr. Eric Hernandez, assistant professor in the School of Engineering. The goal is to determine the actual dynamic live load characteristics of bridge 58N along I-89 in the town of Richmond, and to monitor its structural performance under heavy traffic loads.

“This is a very exciting research project which could have very practical engineering applications in terms of preventive monitoring and diagnostic of our bridge infrastructure” says Dr. Hernandez.

An article by the UVM Transportation Research Center (TRC) entitled, “Bridge Structural Health Monitoring and Diagnostics in Vermont” is featured on the UTC web site.  This research is critically important for today’s infrastructure. The United States limits overall weight of trucks to a maximum of 80,000 pounds on interstate highways, but Maine and Vermont allow 100,000 pounds. A push is underway by trucking companies across the nation for heavier loads in order to allow trucks to drive fewer miles and consume less fuel --but heavier loads present significant structural challenges for an aging infrastructure with a nationwide average bridge age of 43 years, where most of these were designed for a minimum service life of 50 years.

Dr. Hernandez and graduate student Geoff May together with VTrans engineering and research staff strategically installed strain sensors and accelerometers on the bridge deck to monitor its dynamic response to vehicular traffic. Vanasse Hangen Brustlin, a local engineering firm, generated the instrumentation plan and performed material testing of the bridge steel beams in coordination with Dr. Hernandez.

The sensor data collected will be processed and analyzed using structural models of the bridge and signal processing algorithms recently developed by Prof. Hernandez.  Results will yield accurate estimates of live load distribution and provide an overall diagnosis of bridge deck’s structural health. This will enable VTrans to update their current load rating and improve our understanding of the bridges' capacities to withstand overweight traffic loads.

Lessons learned from the project can be applied to other bridges in Vermont and nationwide, ultimately increasing safety and improving the reliability in the flow of commerce.

To read the UTC article visit:

Eric Hernandez joined the CEMS faculty as Assistant Professor of Engineering in the School of Engineering in January of 2011.  His area of expertise is structural engineering with special emphasis in direct and inverse problems in theoretical and experimental structural dynamics.