With completion expected in 2027, the nearly $4 billion Hampton Roads Bridge-Tunnel (HRBT) Expansion Project continues making headlines as the largest highway construction project in Virginia's history. Most recently, officials have been celebrating the major milestones reached in 2025.
VDOT photo
"It was the biggest and most meaningful year to date," said Ryan Banas, HRBT Expansion project director. "We completed mining the twin tunnels, setting records for daily production rates for a tunnel boring machine [TBM] of its size.
"We also opened the first two lanes of the new eight-lane South Trestle Bridge that carries traffic between the facility's South Island and Willoughby Spit in Norfolk. Additionally, many traffic shifts of various lengths were completed on the eastbound roadway in Norfolk, totaling nearly six miles of new and widened roadway open to traffic."
Banas explained that with so much work taking place beneath the ground and out of view of the traveling public, opening the new South Trestle Bridge was a celebration for everyone involved.
"For our crews, it meant having the satisfaction of knowing they contributed to what is thought to be the widest bridge in Virginia, at 202 feet. For the public, it meant finally having the opportunity to drive across the very structure they've been seeing rise up from the bottom of the bay for the last four years.
"It's very humbling to see the first vehicles traverse a structure that is designed to handle more than 130,000 cars a day, with a lifespan that will exceed 100 years. It's awesome to think of the billions of trips the new structure will support over its lifespan."
VDOT photo
Hampton Roads Connector Partners (HRCP), a design-build team, is constructing the project. HRCP is a joint venture consisting of multiple partners, with Dragados USA serving as lead contractor and HDR and Mott MacDonald as lead designers.
Banas also noted the project would not be possible without the collaboration of the Hampton Roads Transportation Accountability Commission (HRTAC).
"Ninety-two percent of the funds for the expansion are raised in the region, and HRTAC manages the funds through a commission of locally elected leaders and executives. These funds are earmarked for projects of regional significance that increase capacity."
Banas said experience has been crucial to the success of the project.
"The Virginia Department of Transportation [VDOT] has relied heavily on the experience of fellow owners in its preparation for the project, the years of expertise brought by the project's design-builder to tackle such a massive undertaking and the knowledge of the nearly 2,000 engineers, craftspeople and support staff to tirelessly deliver the project."
Breakthrough day was particularly meaningful, with eyes from around the tunneling world laser-focused on the project.
"Mary the TBM emerged through the headwall after 99 weeks of mining her two tunnels. It marked the completion of years of planning for the twin tunnels and the culmination of a generational tunnel project coming to fruition. VDOT's Commissioner Stephen Brich orchestrated a series of remarks from guests of honor, including U.S. Transportation Secretary Sean Duffy and Virginia Governor Glenn Youngkin.
VDOT photo
"The governor highlighted the significance of the expansion project, especially for military readiness by ensuring personnel are ready to respond when duty calls. Most rewarding was the sense of accomplishment clearly visible on the faces of the men and women who worked tirelessly and diligently throughout the tunneling process."
According to Banas, the tunnels were each completed in less than one year. Excavation occurred 24 hours a day, five days a week. Weekends were reserved for equipment maintenance and supporting activities that were conducted around the clock to support the next week's mining operations.
"Mary moved more than one million cubic yards of material. Once excavated by the cutterhead, material was mixed with slurry and transported up to three miles to the surface of South Island through 22-inch diameter steel pipe. The pipe, delivering as much as 13,200 gallons of soil-slurry mixture per minute, emptied into the slurry treatment plant. Here, soil was separated from the slurry, recovering soil as fine as half the thickness of a human hair.
"Simultaneously, the TBM placed concrete segments to build the tunnel liner. Each ring, measuring six feet to six inches in width, was composed of nine concrete segments weighing as much as 20 tons. In total 21,465 segments were placed, creating 2,385 rings, leaving behind two tunnels with a combined length of just over three miles."
Mary is more than 46 ft. in diameter, and is composed of five major pieces, with a total weight just under 10 million lbs. Upon her cutterhead, which can rotate up to 2.5 times per minute, Mary is equipped with 198 scrapers, 26-disc cutters and 11 center tools specifically designed for the project's subsurface conditions.
Dismantling Mary began almost immediately upon completion of mining.
VDOT photo
"The process is lengthy and quite delicate, ironic given the massive scale on which the machine operates," said Banas. "Crews very carefully unbolt, cut and dismantle the machine in pieces prior to preparing for shipment back to the manufacturer. It's very likely that parts and pieces of the machine will be used in future TBMs once properly inspected and maintained. It's expected that the last pieces of Mary will leave the project in February 2026."
Banas said one of the biggest challenges for crews is continued coordination among the project areas.
"In any other scenario, the HRBT Expansion Project would be divided into multiple smaller projects. As a mega project, the HRBT has the challenge of ensuring multiple crews and operations can happen simultaneously, while still moving more than 100,000 vehicles a day. On top of the HRBT, VDOT has multiple other projects under way in the Interstate 64 corridor."
Ongoing work includes completion of the tunnel approach structures, phasing the South Trestle Bridge to the new and existing tunnels; completion of a new North Trestle Westbound Bridge; finishing the new Mallory Street Bridge in Hampton; demolition of the existing westbound and eastbound trestles; and interstate and bridge widening in the existing right-of-way along the project's 10-mi. corridor.
On the North and South Islands where tunneling occurred, more than a dozen buildings are being constructed to house maintenance and tunnel support operations and a new traffic operations center. In the tunnel, crews are hard at work constructing the roadway, installing safety features and completing the tunnel systems that will allow for a safe trip across the harbor.
Banas said tunneling for the twin tunnel was a mirror image of the first bore, except it was approximately 36 ft. longer, due to its curved alignment adjacent to the first tunnel. The second tunnel was completed three weeks faster than the first, due to lessons learned along the way.
VDOT photo
"To begin the second tunnel, the cutterhead and shield had to be turned around and aligned to the headwall. Nitrogen sled technology aided in turning the cutterhead and shield with needing to dismantle the entire machine. This simplistic, yet innovative technology saved the project months and also set world records along the way.
"The four trailing gantries were then extracted from the first tunnel, lifted to the top of the North Island using two 800-ton cranes, turned and set back into the cell to be reattached to the TBM to begin the second bore."
The South Trestle Bridge added 1.2 mi. of new deck length to the facility's inventory. Concrete pipe piles were driven upwards of 80 ft. into the bay bottom; more than 800 precast concrete beams were placed; and stainless steel and carbon fiber reinforcement were used to extend the bridge's service life, along with low permeability concrete that resists chloride intrusion and prolongs the onset of corrosion.
Heavy equipment on the job has included 600 and 800-ton cranes, barges, tugboats, unmanned survey boats and a special beam launcher that was erected on site to set nearly 100 girders for the new North Trestle Bridge. A slurry treatment plant, the largest in North America, also has played an important role.
Chief materials include concrete, stainless steel, carbon fiber reinforcement, aggregate, armor stone, ballast, precast concrete beams, steel reinforcing fibers and numerous precast elements.
As for the weather, said Banas, "We're very fortunate in Virginia in that we have a very temperate climate that's conducive to year-round construction. Working adjacent to the Chesapeake Bay means we have to keep an eye to the sky for quick afternoon storms. Our contractor considers the likely occurrence of weather in its schedule and works alternate shifts when necessary."
Banas acknowledged it's tremendously satisfying to be involved in such a monumental project.
"It's an absolute honor for each and every person working on the HRBT Expansion Project to be part of such an amazing undertaking. For many, this will be the largest project of their career. Make no mistake, a project like the HRBT Expansion is one that sits at the top of your resume for the rest of your career, and long after in the stories we'll tell." CEG
