Delaying Bridge Replacement with Structural Health Monitoring Is Projected to Yield an $85 Million Net Present Value Benefit Over 10 Years.
WVDOT's SMART Grant Project Estimated Benefits Based on a Structural Health Monitoring Proof-of-Concept Deployment on a Single Bridge over the Ohio River.
Huntington
Proctorville
West Virginia Structural Health Monitoring Project Implementation Report
Summary Information
Aging and structurally deficient bridges continue to increase the need for effective, efficient, and scalable inspection and maintenance strategies. To address this challenge, this SMART grant project evaluated whether continuous structural health monitoring (SHM) data could identify bridge deterioration, support incident response, and improve long-term asset management. The West Virginia Department of Transportation (WVDOT) Division of Highways installed a wireless SHM system with 57 sensors on the East Huntington/Gunner Gatski Bridge from November 18 to 22, 2024. The study evaluated system data collected between the November 2024 installation and March 1, 2025, the end of the performance period. The cable-stay bridge carried more than 14,000 vehicles per day between Huntington, West Virginia, and Proctorville, Ohio. The system included 39 accelerometers (20 on the cables and 19 on the deck and towers), six tiltmeters, four crackmeters, six displacement sensors, a weather station, and a vessel-impact detection system. The study proposed extending monitoring to six additional Ohio River bridges.
METHODOLOGY
The Stage 1 field evaluation compared 2025 sensor measurements with cable-frequency measurements from 2018 and 2022 and with outputs from a finite-element analytical model. The study assessed whether the system could detect deterioration and extreme events, deliver threshold alerts within 10 minutes, and inform inspection and maintenance decisions. Notification performance was tested by temporarily lowering one sensor threshold. The study also analyzed bridge-maintenance records and data from the only known extreme event during the performance period, a magnitude 3.3 earthquake. Separately, the study used an illustrative present-value calculation to estimate the effect of postponing replacement of a hypothetical $500 million bridge for 10 years, with a three percent annual discount rate and assumed annual maintenance costs of five million dollars.
FINDINGS
- The illustrative calculation valued the 10-year replacement deferral at $128 million in present-day savings. After subtracting $42.65 million in present-value maintenance costs, the estimated net benefit was approximately $85 million. This saving was expected to cover the anticipated costs of SHM monitoring on the proposed six bridges.
- The measured cable frequencies showed strong consistency with historical measurements, with 19 of 20 frequencies falling within two percent of the average values reported in 2018 and 2022.
- The system captured the only known extreme event during the performance period, a magnitude 3.3 earthquake on December 16, 2024. Stable pylon vibration characteristics after the event indicated that the pylon likely did not sustain significant damage.
- In a controlled notification test, email alerts reached project personnel in an average of five minutes and a maximum of seven minutes, meeting the 10-minute target. The study covered a short monitoring period, and sensors were installed only at selected locations. The study cautioned that sensor anomalies did not always indicate damage and recommended corroborating the data through periodic visual inspections or other nondestructive evaluation methods.
