States discovering new partners, tools, and uses for bridge monitoring

By Chris McCahill

The condition of our nation’s bridges is slowly improving, but they still need a great deal of work. According to FHWA, 24 percent of bridges (close to 150,000 in total) are deficient. Monitoring those bridges and managing their maintenance can be challenging and costly for transportation agencies. However, innovative techniques being used in some states make this task easier, save money, and provide new information about how travelers are using the nation’s bridges.

States have had manual bridge inspection programs in place for many decades, but some states are now ramping up their monitoring programs by incorporating wireless sensors that report information about bridge conditions in real-time. Although these systems can cost upwards of $50,000 per bridge, they can help agencies avoid premature investments and potentially save hundreds of thousands of dollars. South Carolina installed wireless sensors on eight bridges and learned that many are in better shape than earlier inspections had suggested, requiring only modest retrofits rather than full replacements. In five years, the monitors have saved the state an estimated $5 million in unnecessary repairs. The data, which can be accessed at any time by transportation agency personnel, also allowed the South Carolina DOT to monitor bridge performance during high-wind events and even to identify and address problems with overweight traffic using its bridges at night.

Other states have put similar monitoring programs in place. The Colorado DOT began testing the devices on one of its more complex bridges in April. Other stakeholders are also interested in these new technologies and are willing to lend support in keeping infrastructure up-to-date. Transportation officials from the state of Michigan met recently with a coalition from the soybean industry, which relies on the state’s bridges to move crops and equipment, to discuss upgrading its monitoring program. One group in particular, the Soy Transportation Coalition, offers grants for states to help launch pilot projects.

Chris McCahill is a Senior Associate at SSTI.