Sanitary District of Decatur Projects

SPRING CREEK PIPE BRIDGE REPLACEMENT

Farnsworth Group was responsible for the replacement and upgrade of an existing aerial sanitary sewer crossing over Spring Creek. The existing 30-inch sanitary sewer main was supported by concrete piers in the flow-line of Spring Creek. Over the years, the piers had settled and shifted. The Sanitary District wanted to replace the piers with a structural steel bridge to support a new upsized 42-inch sanitary sewer main from concrete piers located on each bank of the creek. The structural steel bridge was fabricated from Cor-Ten (weathering steel) as a low-maintenance, long-life material option.

STEVEN’S CREEK SEWER REPAIRS

Over the years, Steven’s Creek has filled in and blocked off the three drainage culvert pipes under the District’s existing 42-inch sanitary sewer interceptor main. The culverts and the flowline of the creek had filled in up to the top of this interceptor sewer pipe on the upstream side with roots, tree limbs, trash, and debris, which was causing additional undercutting and erosion on the downstream side. The design included re-grading and installation of revetment block along the creek to provide a minimum of 18-inches of cover over the top of the interceptor sewer pipe and stabilization of the creek channel.

WILDWOOD SEWER REPAIRS

Wildwood Creek had eroded along the banks, exposing the District’s 15-inch sanitary sewer interceptor main. The design included re-grading the banks along the creek to provide a minimum of 3 feet of cover over the top of the pipe and stabilizing the creek banks with riprap. An existing 8-inch City of Decatur sanitary sewer main that connected into the District’s15-inch interceptor was also exposed with an aerial crossing over the creek. A structural steel support bridge was designed with helical steel piers and concrete abutments to support this 8-inch aerial crossing.