Built as the first world-class world-class complex in 1957, the Hampton Roads Bridge-Tunnel was an engineering milestone in a natural port that is already rich in history, from the landing point for travelers who would establish the first permanent English settlement at Jamestown to the first battle of Ironclad ships during the Civil War.
Now, almost 50 years after it has been increased with a parallel bridge tunnel to house the growing traffic to the I-64, the famous crossing again makes history through the largest road road construction project, a $ 3.9 million expansion program started by 2020, which will double the capacity with two new boring tunnels of 7,900 feet and almost 17,000 feet.
The tunnels are part of a 10 -kilometer runner of the project that covers both sides of the port. Hampton Roads Connector Partners (HRCP) – a joint Dragados design company USA, Vinci, Dodin Camenon Bernard and FlatIRON builders – also oversees 25 new and reconstructed bridges and incorporations of road capacity. HDR and Mott Macdonald are the main project designers.
Mary, the tunnel boring machine, arrived on the existing artificial island of the project and was launched on South Island.
Photo courtesy Virginia Dept. transportation
Properly, the “stars” of the multifaceted program have been linked to local history. Mary, the 430 -foot variable tunnel machine of 4,700 tonnes of tunnel density bored with the task of excavating the 45 -foot tubes below one of the most popular port entrances in the country, Honor Mary Winston Jackson, a NASA math and engineer who worked at the Langley Research Center and was performed in the movie “ Hidden figures ”.
Mary’s couple, a 92,500 square meter Slurry treatment plant, was named by Katherine Johnson, a NASA colleague in Jackson. The plant is designed to receive a flow of 14,000 gallons per minute and has one of the largest saved units.
Mary completed the first tube that linked the existing artificial islands of the Pont-Tunnel complex in May 2024, and entered a welcome moat especially built after 13 months of plowing up to 100 feet below the riverbed. After an elaborate procedure of change and routine maintenance, the machine moved again in the following October and goes to the court to complete the mining of the second tunnel this summer, according to VDOT.
In early May, the tunnel boring machine reached the deepest point of its return route to more than 170 feet below the surface of the port of Hampton Roads.
Photo courtesy Virginia Dept. transportation
Superlatives and struggles
The importance of managing only the fourth U.S. use of a TBM to excavate a new road tunnel is not lost to the project team.
“More men have been on the moon and the number of road tunnels built with this technology,” says Ryan Banas, director of the VDOT construction manager, HNTB Corp.
It is perhaps important, it adds Banas, is the funding structure that makes the mass project possible, with more than 90% from regional sales and gas taxes provided through the Hampton Road Transportation Account Accountant Commission. The Agency will use the income of the express lanes of the expansion completed to finance other infrastructure projects in the region.
“More men have been to the Moon and the number of road tunnels built through this technology.”
—Ryan Banas, project director, HNTB Corp.
The expansion, says Banas, will “open the doors to many other projects that will be invested here during the nearby generations.”
With great size and complexity they have also had great challenges. Last year, VDOT reviewed its 2019 comprehensive agreement with HRCP, citing what the agency called “unforeseen cost impacts and programs”. Vdot said that at that time, he said that at that time, “it would provide the certainty of construction programming, improve the accountability of the calendar of contractors and reduce the potential of litigation”, while retaining the original budget.
Banas refused to deepen the reasons for reestablishment, saying only that, given the “pure magnitude of expansion, bulky amounts of materials and complexity”, the review of the integral agreement was determined to be in the best interest of all those involved.
“The substantial completion goal is still February 2027,” he adds, noting that HRCP has an incentive of $ 90 million to end in September 2026. “They work hard to achieve this plus.”
A new eight -lane bridge is being built south of South. Temporary bridges help build and traffic flow as the old truest is demolished.
Photo courtesy Virginia Dept. transportation
Dig
To undermine the two new tunnels, HRCP expanded the two existing artificial islands of the Pont-Tunnel by various hectares with Bund Rock walls. Mary began his initial journey from a specially built moat of 65 feet on the southern island, where the slurry treatment plant is also located.
Traveling approximately 50 feet a day, Mary extracted approximately 50 feet deeper than the existing tunnels to a highly compressed sand and clay layer. With each thrust of 6.5 feet forward, the TBM placed a coating ring consisting of nine prefabricated concrete segments of 12 tons 6 feet wide.
Regular reinforcement bombs helped maintain the slurry system by working at optimum capacity during 24/7 as Maria advanced, with up to 15 minutes needed for excavated material to the slurry plant before the Bentonite slurry filtered into the TBM was sent.
On the North Island, HRCP read for the arrival of Mary with the construction of a 75 -feet -footed grave 160 feet with a 9 -feet -thick base slab, heavy enough to withstand the buoyancy. Vdot says that the discharge of concrete of 31 hours for the slab was the largest continuous dump in the history of the agency, with a fleet of more than 30 trucks that made multiple trips for lots for lots to transport almost 5,500 meters of concrete.
Following the advance of Mary of May 2024, positioning the TBM for the return trip required a similarly complex operation that aimed to keep most of the machine intact possible. Juan-Miguel Pérez, who served as an executive of the HRCP project for the early stages of expansion, told Enr that “minimizing the dismantling would reduce the time needed to deconstruct and rebuild the TBM, helping us to return to tunnel more rapidly.”
With the 875 and 750 tonnes of tracker that had removed the TBM loungers in four pieces, the Cape and the coat of arms of 2,500 tons of Mary turned and aligned for the second tunnel by using nitrogen skates, the first application of this type in the United States and the heaviest twist on the shield, according to VDOT. Completed in just 11 hours, the maneuver “was a clean and well -planned operation,” adds Pérez.
Mary, the tunnel boring machine, is named Mary Winston Jackson, a NASA engineer and engineer who worked at the next Langley Research Center, and was performed in the movie “Hidden Figures”.
Photo courtesy Virginia Dept. transportation
Toward home
Taking advantage of the experience obtained during the excavation of the first tunnel, HRCP has been able to improve efficiency. Mid-April saw the most productive week still, with the 420-foot TBM mining and placing 63 rings. When Maria makes her arrival in September return to the southern island, the TBM will have placed 2,385 rings for a total of 21,600 segments.
The relative softness of the boring phase of the tunnel has so far demonstrated that the only “surprise” has been discovering the remains of a North -American Mastodon, which is estimated to be up to 50,000 years old. It is currently used in public presentations on the project, the remains will be donated to the Virginia Natural History Museum.
In the meantime, HRCP continues to fit the first tunnel with ballast, drainage, road, lighting, ventilation and security systems. Again on the surface, the new trees also ended up. Constructed of 54-in-day cylindrical batteries driven to depths of 70 to 110 feet, the structures are approximately 12 to 15 feet higher than the original trees to improve the resilience of corrosive storm waves and the potential increase in sea level. Interval lengths range from 60 feet to 125 feet.
This summer, VDOT plans to move two traffic lanes to the new South Trestle, which, with 67,568 square meters of bridal deck, will eventually carry the eight lanes between the tunnels and the Norfolk side. To the north, where the alignment required to keep the links separated in a north and south direction with Hampton, HRCP will soon pass traffic to the new west bar. As the old trees are demolished, the new structures will continue to direct the traffic in and out of the existing tunnels until the new tubes are ready.
Claudio Comeiotti, who took over the HRCP project executive earlier this year, says that the achievement of these and subsequent milestones in the calendar “will require the same approach, care and teamwork” that has brought the project so far, including the security of security as a maximum priority.
“A mistake, no matter how small it may seem, can fight operations, impact schedules, jeopardize critical milestones and, most importantly, put life at risk,” says Cimiotti. “We just can’t afford to let this happen.”
