By rosebell
As the first time that this method has been used in the US, Nitrogen skates have been used to turn the TBM on the Hampton Roads-Bridge Tunnel Expansion (HRBT).
In order to completing the second bore, TBM Mary with 14m-diameter that broke through the North Island headwall in April 2024, required to be turned, whereas currently the 2,500-ton cutterhead has been turned 180 degrees, using nitrogen skates by a crew of 35 people in eight hours.
According to HRCP assistant resident engineer Lion Nitschke: “The major challenge was working in the tight space of the pit.It will now take five months to remove and turn the gantries, while at the same time installing buoyancy measures to prevent the tunnel from lifting.”
Considering that TBM Jill was rotated in the reception chamber on London’s Silvertown Tunnel project in March last year, it is the second time the nitrogen technology has been used in the world.
As the largest highway construction project in Virginia’s history and the state’s first bored road tunnel, the US$3.9bn HRBT intends to ease congestion along a 16km corridor on the I-64 through the addition of twin, two-lane bored tunnels beneath the harbour from Hampton to Norfolk and the widening of four-lane segments.
Construction of this project is up to Hampton Roads Connector Partners (HRCP), a consortium of Dragados USA, Vinci, Flatiron Constructors, and Dodin Campenon Bernard.
While a18 months delay was announced for completion of this project in April by VDOT, it is now scheduled to reach substantial completion on February 26, 2027, and the determined date fo final completion is August 27, 2027; however, HRCP has an early completion incentive of US$90m if substantial completion is finished by September 2026.
