Joe Green, an iron worker with Kanzaa Construction of Topeka, Kan., tightens bolts atop the roadway-topped tunnel that is under construction to replace the bridge at Washington and Clark streets. A total of 10,000 bolts have to be tightened to 150 to 300 pounds of torque, he said. After the arch is completed Kanzaa will start building the foundation for two more concrete footings for the foundation of retaining walls at each end of the tunnel, said Felipe Bobadilla, project manager for Kanzaa. Once the retaining walls are in place workers can begin to fill in the remaining space with back fill to the road level. The 80-year-old bridge was demolished in August 2010 after having been closed since January 2009. It is the lone span along Vicksburg’s main north-south corridor connecting downtown and Interstate 20 The project cost is not to exceed $8.6 million. Bobadilla said he expects the project to be completed by summer.