Country Place Force Main Replacement
Spalding DeDecker (SD) was contracted by the City of Novi to prepare construction plans for improvements to an existing sanitary sewer pump station and the associated outlet forcemain. The station has high flow volumes and should a failure occur, the sewage could back up into many residents’ basements in just a couple hours. A recent report also outlined the need for higher flow pumps to more efficiently meet the peak demands.
The existing 10” forcemain that was installed 40 years ago is Asbestos Cement pipe, which is known to be fragile when exposed. Due to the high volume of flow through the system, a new 10” HDPE forcemain is being installed from the pump station to a new manhole at the outlet. The pump station cannot be offline.
The new forcemain was designed to be constructed through horizontal directional drilling to limit the disturbance to the existing development. The available route for the proposed replacement forcemain includes two sharp 90-degree bends. Although the main was installed via directional drilling, the 10” pipe cannot be drilled through a tight radius turn; therefore, open cut methods were used at these locations. Preformed 90-degree HDPE bends were electrofused in place to assure the integrity of the installed forcemain.
Aside from documenting and observing the standard construction processes, SD worked closely with the awarded contractor to see that measures were taken which immediately addressed any damage to the existing fragile Asbestos Cement force main.