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Coolidge Place

Oak Park, Michigan

Stormwater Detention


Coolidge Place Condominiums 


Nowak & Fraus 


Inner City Contracting 


Fall 2019

Technical Description:

  • 1,618' of 54" Aluminized Steel Type 2, 14 GA

Demand for affordable housing prompted the redevelopment of multiple residential houses into 64 affordable apartments in Oak Park, MI. The redevelopment called for a new stormwater system to capture 12,517 cubic feet of runoff from the new building’s roof and other impervious surfaces. Since there was no central location for water storage, engineers at Norwak & Fraus designed the stormwater drainage pipe in a linear approach for both storage and conveyance for the 100-year storm event.

Engineers reviewed several material options, but ultimately choses corrugated metal pipe (CMP), as it offered sufficient size and ability to accept HS-25 loading with 12 inches of minimum soil cover. The pipe size was also a concern, as the manhole needed to be 6-foot in diameter or smaller. For these reasons, the design team selected 54-inch CMP pipe made from 14-gage Aluminized Type 2 (ALT2) which meets MDOT’s 50-year service life.

The detention pipe was backfilled and compacted with MDOT 6-A aggregate and a 20-mil HDPE liner was placed over the top of the pipe to protect against excessive salting conditions and shallow soil cover.

“The project went well as coordinating with Contech was critical as on-site room was limited, such that as we were able to coordinate pipe deliveries,” said Ryan Lynn, Site Superintendent with Inner City Contracting of Detroit, MI. “The project went smoothly as all the parts and pieces matched the detailed shop drawings and were easy to install.”

Technical Description:

  • 1,618' of 54" Aluminized Steel Type 2, 14 GA

800-338-1122 |
Project #: 609,186


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