Construction on one of several Virgin River Gorge bridges in the far northwest corner of Arizona starts next week. The Arizona Department of Transportation calls the 27-million-dollar project the largest on its portion of Interstate-15 in 40 years. Much of the funding comes from a federal grant. The project includes replacing girders, decks and railings on the bridge and widening the roadway. It is expected to take two years. Transportation crews will begin setting up traffic control Tuesday. At least one lane in each direction will be open during the construction phase. The Transportation Department says it ultimately will have to rehabilitate all eight of the Virgin River Gorge bridges. More than one-point-four-million commercial trucks travel on Arizona's portion of the interstate each year.