14 Mile Transmission Main Loop Project Purpose, Challenges, and Successful Completion

Great Lakes Water Authority (GLWA) experienced a catastrophic failure of a prestressed concrete cylinder pipe (PCCP) segment in the 14 Mile Rd. Transmission Main (TM). This TM was not part of a looped system, and this failure resulted in the loss of water service to residents in GLWA service area. GLWA decided that the 14 Mile Rd. TM must be interconnected to the 8 Mile Rd. TM so it is in a looped system. A route study determined that the 14 Mile Rd. TM Loop should be placed in Michigan Department of Transportation (MDOT) right of way (R/W) and in the City of Novi’s city streets. This paper discusses the need for the pipeline, benefits and challenges associated with installing the pipe in an MDOT R/W, the tunnel design and construction requirements, the micropile design and bidding strategy, as well as other construction and design lessons learned.