ROADS/BRIDGES: “Living” bridge looks to redefine smart infrastructure

Sept. 21, 2015
Designed by HNTB engineers, the New England bridge will monitor status, traffic and more
Monitoring the status and daily traffic load on a given bridge is an almost impossible task using traditional methodologies. The advent of new smart infrastructure technology, however, is looking to change the mindset regarding bridge inspections and monitoring in the New England region. The Memorial Bridge, which runs over the Piscataqua River between New Hampshire and Maine, a 1,200-ft-long, two-year-old bridge, is set to become a “living bridge”—a piece of self-diagnosing, self-reporting smart infrastructure studded with approximately 250 sensors. This array will monitor traffic, vibration, stress, temperature, wind, humidity and precipitation simultaneously, in addition to accumulating values related to water quality, turbidity and the effects of any ship impacts. These sensors will be powered by a tidal energy turbine on one of the bridge piers. The $355,000 project, launched by University of New Hampshire assistant professor Erin Bell, expands on a National Science Foundation effort with the New Hampshire Department of Transportation (NHDOT), the Maine Department of Transportation and the Federal Highway Administration, which is funding the project. The HNTB design includes unusual gussetless truss connections, a structural metalized steel coating and a vertical-lift balance system. Over the next three years, accumulated data will be analyzed to determine this application’s viability to other bridges. “Getting some of the stresses on that new [gussetless] connection area is important,” says L. Robert Landry Jr., consulting design chief for NHDOT. Truss bridges with hard-to-maintain gusset plates have fallen under intense scrutiny even since Minneapolis’ I-35W bridge collapse, Landry said, therefore if the gussetless connection performs well, “it will move a long way to trusses coming back into favor.”