Northeast Remsco executed a 1,359-ft radius curve for a length of 160 ft to complete this complex project.

Northeast Remsco Completes First Curved Microtunnel in U.S.

O n May 19, 2010 Northeast Remsco Construction successfully completed a planned, curved microtunnel in Hartford, Conn., on behalf of the Metropolitan District Commission. The project was designed by AECOM.

This was part of Hartford’s $1.6 billion Clean Water Project. The project includes three basic elements: 1) Reduction of combined sewer overflows (CSOs) with the Hartford central sewer system, 2) Elimination of sanitary sewer overflows (SSOs) in the sanitary sewers of Wethersfield, West Hartford, Windsor, Rocky Hill and Newington and 3) Nitrogen reductions.

Project personnel celebrate the breakthrough for the 600-ft drive. The accuracy was less than ½ in. both horizontally and vertically.

Although much of the project involved trenchless technology, this section had originally been planned as open-cut. However, the density of other utility services in the vicinity of this section encouraged the contractor, Northeast Remsco, to suggest the alternative method of microtunneling. Detailed study of the obstacles along the route necessitated that the drive would need to be curved. Such was the complexity of these obstacles that the precise alignment was modified several times until the most suitable course was finalized.

The machine used for this drive was the company-owned Herrenknecht AVND 1800AB MTBM equipped with a SLS Microtunnelling LT guidance system supplied by VMT GmbH.

VMT also supplied an experienced engineer to oversee the guidance of the machine, which completed the 600-ft drive in just nine days while undertaking a curve of 1,359 ft radius for a length of 160 ft to complete this complex project. The breakthrough accuracy was less than ½ in. both horizontally and vertically.