Virginia’s Hampton Roads Bridge

A US$3.8bn (£3.1bn) project to upgrade a motorway and build new tunnels between Hampton and Norfolk in Virginia, USA, has taken a step forward with the assembly of a giant tunnel boring machine (TBM).

The Hampton Roads Bridge-Tunnel Expansion Project will widen the current four-lane segments along nearly 16km of the I-64 corridor in Norfolk and Hampton.

It will also add two new twin two lane bridge tunnels underneath the Hampton Road’s harbour that will carry eastbound traffic from Hampton to Norfolk. The new tunnels will be bored next to the existing Hampton Roads Bridge-Tunnel, which comprises two immersed tube tunnels.

The expansion aims to increase capacity, ease major congestion and enhance travel time reliability. It is the largest highway construction project in Virginia’s history and is scheduled for completion in November 2025.

The Hampton Roads Connector Partners (HRCP) is the joint construction venture delivering the project.

In a recent project update, Hampton Roads Bridge-Tunnel Expansion project director Jim Utterback said that work is underway to assemble the 14m diameter Herrenknecht TBM named Mary that will be used to bore the new tunnels.

In January, the 430t TBM cutterhead was lowered into the launch shaft on the South Island and attached to the TBM.

Once all the testing is complete, the TBM will launch from the Norfolk side of the harbour and begin its journey towards Hampton.

It will bore at a rate of about 15m per day until it reaches the Yorktown layer of soil, which is around 15m below the current tunnels.

The TBM will excavate the tunnels with a circular cross section through the soil. The process will take more than two years.

The slurry treatment plant (STP) will be critical to the tunnel mining operation. The plant will supply slurry to the TBM during the mining process and will also separate and filter the excavated soil upon its return to the STP.

The de-sanding unit of the project’s STP is one of the largest in North America, is electric powered, and will operate 24 hours a day while the boring process is underway.

Utterback also said that the past month has seen construction crews make final preparations to allow the opening of the new temporary South Island eastbound marine trestle.

This trestle will temporarily carry traffic coming out of the eastbound tunnel so crews can begin demolition of the existing bridge. That demolition will allow crews to continue pile driving for the new permanent trestle and begin the necessary expansion of the South Island.

On top of this, crews have made progress on bridge rehabilitation activities underneath the Willoughby Bay, Mason Creek and Oastes Creek bridges, as well as all the bridge and roadway widening activities. The landside widening work is the enabler for the new bridge tunnel capacity.

The Virginia Department of Transportation gave the project the go-ahead in 2020 when it issued a notice to proceed to begin building the project.

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