Each day during the construction season, Stoneco Quarries sends up to 400 trucks loaded with limestone aggregate across a bridge on Sterns Road in Monroe County, Mich. Early in 1997, however, county officials notified quarry owners that the load rating for the old steel bridge would have to be lowered because of deterioration during the last several years. Furthermore, it would be five years before Monroe County could schedule bridge replacement.
Fortunately, Stoneco's owner, S.E. Johnson Companies Inc., is an experienced highway and bridge contractor working in the North Central states. S.E. Johnson confronted the problem head-on and decided to replace the bridge for the Monroe County Road Commission. By working around-the-clock and using precast-concrete bridge components, crews were able to build the new 28-foot-span bridge in just five days, with minimal interference with aggregate deliveries.
Although the old bridge was 24 feet wide, engineers decided to give the new structure a total width of 44 feet. To provide the necessary roadway width, eight precast arch sections were required. Two precast headwalls and four wing walls also were used. To speed construction, crews used a 120-ton crane to place the pieces, the largest of which weighed more than 20 tons.