Though still unfinished, the 1,000-foot span over the Monongahela River at Star City is already loaded with 770 sensors, 28 data-collection boxes and a central unit called the brain. Together, they make up what engineer Shamir Shoukry says is the smartest bridge in the world. According to a story in the Associated Press on December 16. “Smart” bridges and roads that communicate with their makers through built-in sensors are becoming more common as engineers worldwide try to determine whether long-held construction assumptions are correct or whether there are better ways to build. Several states have smart structures, and at least one span — Florida's Sunshine Skyway Bridge — may have more sensors than Star City. “But if we're talking about density,'' Shoukry says, “this would be the most. This is one of the most extensively instrumented bridges in the world.'' The sensors measure minuscule, visibly undetectable changes in steel girders and support structures, in piers and abutments, in concrete and rebar. If a crack is about to occur, the sensors should detect it. If settling shifts the inclination by as little as one-millionth of a degree, that will be recognized and recorded. The state Division of Highways is spending nearly $18 million on the bridge and decided to invest an additional $471,000 in Shoukry's project to learn more about what causes stress and deterioration of expensive infrastructure. The information may help the state make smaller, less costly repairs while problems are still manageable, Deputy Commissioner Norman Roush says. Already, West Virginia's demonstration projects have yielded results. On the Corridor H project, the state learned that concrete slabs 20 feet long are prone to crack, while those 15 feet long are not. The state of Pennsylvania, which had problems with cracks on Interstate 81, is changing its slab length based on those results, Roush says.