City of Milwaukee Sewers

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Shotcrete Lining of Combined Sewers

The contract awarded to ACT by the City of Milwaukee was for the structural lining of 1,650 feet of a 100 year old brick sewer.

Prior to shotcrete application, the brick surface of the sewer was cleaned with a 7000 psi water blaster to remove all dirt and debris. A sewage by-pass system was installed allowing the sewer to remain in operation and enable our work to be completed in the dry. Reinforcing steel hoops were installed throughout the length of the sewer at 3 inch centers requiring custom cutting, bending and manufacturing of the reinforcement.

All personnel, material and equipment were lowered through an existing 36 inch diameter manhole to a depth of 45 feet below grade to access the work areas. All work was completed in a confined space environment.

Upstream and downstream bulkheads along with two 15 inch diameter PVC pipes were installed to form a live sewage by-pass system. The system was capable of handling sewer flows ranging from 20 to 35 cubic feet per second and allowed the work to progress while the sewer remained in full operation.

A traffic control plan was implemented and maintained throughout duration of contract.