New award in the US: design-build contract for the “Potomac River Tunnel” in Washington DC

23 November 2023New award in the US: design-build contract for the "Potomac River Tunnel" in Washington DC

The ASTM Group has been awarded, through its US-based subsidiary Halmar International, the design-build contract of a tunnel under the Potomac River. The initiative was promoted by DC Water, water authority in the District of Columbia, of which this is the largest project ever assigned.

The project, with a total value of $819 million, was awarded to the joint venture made up by CBNA (70%) and Halmar (30%) and consists of the construction of a series of diversion structures, collection pits and support structures to capture flows from existing mixed sewer overflows along the Potomac River and ultimately convey them to the Blue Plains wastewater treatment plant.

The works will require the use of two Tunnel Boring Machines (TBMs) customized specifically for these soil conditions. In fact, the 5.5-mile-long and 100-foot-deep main tunnel will pass through a variety of geological conditions, developing near Washington DC's landmarks. The duration of the work is estimated to be about 6 years. Construction is estimated to last for about 6 years.

To read the press release click here.