First curved micro drive in the USA
First curved micro drive in the USA Jun 2010
VMT News Release

Taking a turn

To the best of our knowledge, the first microtunnel planned and designed as a curved drive in the United States has just successfully holed through.
On May 19, 2010, Northeast Remsco Construction completed the curved microtunnel in Hartford, Connecticut on behalf of the Metropolitan District Commission.
Designed by AECOM, the microtunnel is part of the US$1.6 billion 'Clean Water Project' currently well underway in Hartford, the State capital of Connecticut. The project includes three basic elements:-
Reduction of combined sewer overflows from the Hartford central sewer system
Elimination of sanitary sewers overflows in the Wethersfield, West Hartford, Windsor, Rocky Hill and Newington areas; and
Nitrogen reductions
Although much of the project involved trenchless technology this section was planned originally as an open trench operation. The density of other utility services in the vicinity however encouraged the contractor Northeast Remsco to suggest the microtunnelling alternative.

Breakthrough bullseye

Detailed study of the obstacles on the route determined that the drive needed to be curved. Such was the complexity of these obstacles, the precise alignment was modified several times until the most suitable route was finalized.
The machine used was the company's 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. The 600ft drive was complete in just 9 days while undertaking a curve of 1,359ft radius for a length of 160ft to complete this complex project. The breakthrough accuracy was less than ½ inch in both horizontal and vertical.
A more in-depth article is being prepared for publication on TunnelTalk within the coming weeks.


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