HRBT Expansion Project

With a budget of more than $3.8 billion, the Hampton Roads Bridge-Tunnel (HRBT) Expansion project for the Virginia Department of Transportation is the largest highway construction project in the state’s history. The project involves widening the current four-lane segments along nearly 10 miles of the I-64 corridor in Norfolk and Hampton, with new twin tunnels across the harbor. The expansion will increase capacity, ease major congestion and enhance travel time reliability.

 

The I-64 HRBT is a 3.5-mile facility with two 2-lane immersed tube tunnels (8,000 ft long) connecting artificial islands, with trestle bridges to shore. The new tunnels will be bored with a 46-ft diameter TBM, 50 ft deeper than the existing tunnels. The project represents only the fourth TBM-bored highway tunnel in the United States (Port of Miami Tunnel, Seattle SR 99 Tunnel and the Parallel Thimble Shoal Tunnel in Virginia are the others), and the second largest TBM used in the country (behind SR 99).

In addition to new tunnel construction, the project involves replacing/building bridge structures (five bridges to be replaced, 23 to be widened), replacing marine trestles and widening of the roadway from two to three lanes plus a driveable shoulder lane in each direction.

 

Project Background
The HRBT Expansion project will provide additional capacity along I-64, a major traffic conduit in the Hampton Roads area in southeastern Virginia. The area is home to 1.7 million residents, the largest Navy base in the world, and one of the major commercial shipping ports on the East Coast. In addition, summertime brings a host of tourists visiting historic destinations in the area, as well as its popular Atlantic beaches.

The original Hampton Roads Bridge-Tunnel opened in 1957, replacing ferry service. It was constructed as an immersed tube tunnel connecting two man-made islands, which are connected to shore via trestle bridges. However, population growth has constrained capacity, leading to routine backups, particularly in the summer months.

Planners from the Virginia Department of Transportation (VDOT) have been considering solutions for more than two decades, with preliminary plans for another crossing dating back to at least the 1990s. Project planning evolved in the 2010s with the development of environmental documents that identified the current project as an alternative to construction of a new bridge or a route that paralleled the Monitor-Merrimac Tunnels (also an immersed tube tunnel) farther to the west.

With a significant portion of the funding in place via the Hampton Roads Transportation Accountability Commission, the Federal Highway Administration issued its Record of Decision in 2017, clearing the way for the project to proceed.

Through discussions with various stakeholders, notably the U.S. Navy and the Port of Virginia, VDOT opted for a tunneled option rather than a bridge, which would minimize disruption and ensure that the shipping channel remained unobstructed during and after construction.

Given the history of immersed tube tunneling in the region – all previous tunnel segments had been built by this method, including the new Elizabeth River Tunnels which opened in 2017 – initial plans leaned toward another immersed tube approach. However, with bored construction being planned for the nearby Chesapeake Bay Bridge-Tunnel District’s Parallel Thimble Shoal Tunnel project and the success of large-diameter bored highway tunnels in Miami and Seattle, VDOT opted to leave the tunnel construction methodology up to the contracting teams during the procurement phase, allowing for either immersed tube or bored construction. During the procurement phase, both of the final bidding teams proposed constructing the tunnel with a soft-ground TBM.In early 2019, VDOT entered into a P3 design-build contract with Hampton Roads Connector Partners to build the project. Hampton Roads Connector Partners includes Dragados USA, Vinci Construction Grands Projects, Flatiron Constructors and Dodin Campenon Bernard, with HDR and Mott MacDonald as design joint venture. The contractor selection culminated a yearlong competitive procurement that evaluated technical proposals and price.

VDOT opted for the P3 design-build model for the project, which involved maintaining traffic during construction and re-routing it to the new facilities afterward – all within a limited alignment with multiple stakeholders. During the procurement, VDOT met with the prospective builders to discuss technical approaches and commercial terms, including value engineering and dispute resolution.

“Based on the size and complexity of the project, we decided to use the P3 design-build model,” said Jim Utterback, HRBT project director for VDOT. “We had numerous meetings with the contracting teams during the procurement process to discuss all aspects of the project and how they planned to approach the work. It was an iterative process that resulted in a plan moving forward that everyone was comfortable with.”

Tunnel Construction
Under the contract, HRCP is responsible for the tunnel and the accompanying roadway and bridge repair/construction work. The existing tunnel stretches between two artificial islands and links Hampton in the north to Norfolk in the south, spanning the entrance to the James River and Hampton Roads. The new tunnels will be built next to the existing tunnels.

A geotechnical investigation during the planning stages identified a zone known as the Yorktown layer – a stiff clay typically over 100 ft deep – as the primary tunneling stratum. HRCP built a tri-cell slurry wall shaft on South Island – the larger of the two manmade islands – as the launch pit for the variable-density Herrenknecht slurry TBM, which arrived in November 2021.

The TBM will drive to North Island – a process expected to last about a year – where it will be rotated on a turntable and head back to the south to complete the tunneling process. The slurry treatment plant is also on site on South Island.

Due to the soft organic silts of the estuary, HRCP improved the ground around the area of the tunnel launch zone using jet grouting and deep soil mixing to facilitate the transition into the Yorktown layer. As of this writing, work on the launch portion of the shaft was complete with the TBM being assembled in the hole, with the cutterhead being lowered in January. It is anticipated that the machine will begin its subaqueous journey in April.

The TBM will install segmental liners as it progresses. The segments are being cast in Cape Charles, Virginia, on the eastern shore of the Chesapeake Bay, and will arrive to the project site by barge. Approximately 50 percent of the total 21,000 segments needed for the project have been cast.

“This is a massive project – not just the technically challenging tunnels, but also the associated marine bridges and roadway work,” Utterback said. “The challenge of building this heavy civil work while being able to maintain 100,000 vehicles a day on the existing roadway makes it huge undertaking. Just being able to be where we are today nearly ready to launch has been an accomplishment. Now we can turn our focus to TBM tunneling.”When complete in late 2025, the HRBT Expansion will double the capacity of the bridge tunnel, easing congestion along the crowded corridor that routinely sees miles-long backups in peak months, as well as ensuring a safe evacuation route in the event of hurricanes and other emergencies. An added benefit of the project is its role in the economic development of the region, enabling the efficient flow of truck traffic to and from the Port of Virginia facilities. VDOT estimates that the HRBT expansion will spur more than $4.6 billion in investment in the region as well as provide 28,000 jobs through the duration of the project.

Meet ‘Mary’

December 14, 2021 was a milestone day for the Hampton Roads Bridge-Tunnel (HRBT) Expansion Project, as the project team celebrated the arrival of the tunnel boring machine at the Port of Virginia.
It is tradition to give a TBM a female name before it starts boring to bring good luck to the project. The HRBT Expansion Project held a naming contest in the fall of 2020. The contest was open to middle school students in Hampton Roads. First place was awarded to a team from Saint Gregory the Great Catholic School in Virginia Beach. They chose the name “Mary the TBM” in honor of Mary Winston Jackson of Hampton, Virginia – mathematician and aerospace engineer at NASA, noted for her pioneering role as an African American woman in the field of science and engineering, and her crucial contributions to the NASA Space Program.

The winning team was in attendance along with dignitaries and regional representatives from the Commonwealth of Virginia, VDOT, Hampton Roads Transportation Accountability Commission , the Port of Virginia and Hampton Roads Connector Partners. All were gathered to welcome Mary to Hampton Roads. After remarks, a scale model of Mary was unveiled during the ceremony.

Fully assembled, the TBM stands 46 ft tall, extends more than 430 ft in length and weighs more than 4,700 tons, or 9 million pounds. The machine is powered by up to 16 electric motors, with its main drive delivering over 7500 horsepower. Depending on soil conditions, it is expected to mine up to 50 ft per day.