The hardest part of the Hampton Roads Bridge-Tunnel Expansion has been finished for almost a year, and most drivers on I-64 have no idea. Both tubes were fully excavated when the tunnel boring machine broke through on September 24, 2025. The machine itself was pulled off site in spring 2026. And the project still will not open until 2027.
That gap — nearly 18 months between the last cut of rock and the first car through the tunnel — is the single most misunderstood thing about tunnel construction, and the HRBT is the best live demonstration of it in the country right now.
What the $3.9 Billion Buys
The HRBT Expansion is a 9.9-mile reconstruction of I-64 from Mallory Street in Hampton to Patrol Road in Norfolk. It is the largest highway construction project in Virginia's history at $3.9 billion, funded through regional sales and gas tax collections plus $200 million from the Commonwealth's SMART SCALE program and $108 million from VDOT.
The scope is much broader than the tunnel:
- Twin two-lane bored tunnels under the harbor, adding four lanes of underwater capacity to the existing four, for eight total
- A third lane and a drivable shoulder added in each direction on the land segments
- Five bridges replaced and 23 widened
- Marine trestle replacement on both approaches
The Virginia Department of Transportation owns the project. Hampton Roads Connector Partners is the design-build contractor — a joint venture of Dragados USA as lead, VINCI Construction Grands Projets, Flatiron Constructors and Dodin Campenon Bernard, with HDR and Mott MacDonald as the design joint venture. The Comprehensive Agreement was executed in April 2019 and notice to proceed was issued in September 2020.
Steel content across five replaced bridges, 23 widened structures and a full trestle replacement is substantial, and it is one reason schedule and material exposure on this job never sat entirely in the tunnel. Contractors pricing similar marine and bridge packages should be tracking structural steel pricing alongside the civil quantities.
Bored Tunnel, Not Immersed Tube
The two existing HRBT tubes are immersed-tube tunnels — precast sections floated into position, sunk into a dredged trench, joined and backfilled. That is the traditional method for a harbor crossing, and it is often cheaper per linear foot than boring.
VDOT went with bored tunnels instead, and the reason is operational rather than structural. An immersed tube requires dredging a trench across the harbor floor, which means closing or restricting a working federal shipping channel for an extended period. Hampton Roads is one of the busiest ports on the East Coast and hosts the largest naval base in the world. Interrupting that channel is not a construction cost — it is an economic and national-security cost, and it does not appear in the bid.
Boring moved the entire operation below the channel bottom. The new tubes run approximately 50 feet beneath the existing tunnels. Traffic on the old tunnels never stopped, and ships never stopped either. VDOT has been explicit that the bored approach eliminated disruption to the federal channel. That is the tradeoff to remember whenever a bored tunnel looks expensive against an immersed-tube alternative: you are frequently buying uninterrupted operations, not just a hole.
One Machine, Two Drives, and a Turnaround Nobody Talks About
The machine, a Herrenknecht unit named Mary after Mary Jackson — the NASA engineer and mathematician from Hampton — is a Variable Density TBM with a cutting wheel 13,990 millimeters across, just under 46 feet. It weighs 4,700 tons. Cutterhead power is 5,600 kW, roughly 7,500 horsepower, developing about 36,947 kNm of torque — on the order of 27 million pound-feet.
The "variable density" designation matters more than the size does. A conventional slurry machine supports the face with a bentonite suspension; an earth pressure balance machine supports it with the conditioned muck itself. A variable-density machine can shift between high-density suspension and slurry modes as the ground changes. Hampton Roads is heterogeneous marine sediment — sands, clays, and layers that change over short distances under significant hydrostatic head. A machine that can only do one thing gets into trouble in ground like that. Mary installed the precast segmental rings as she advanced, so the tunnel was structurally complete behind her at all times.
The sequence is the part general coverage skips almost entirely:
| Milestone | Date |
|---|---|
| Launch, South Island (Norfolk side) | April 2023 |
| First breakthrough, North Island | April 17, 2024 |
| Turnaround and relaunch | Roughly six months later, late 2024 |
| Final breakthrough, South Island | September 24, 2025 |
| Machine demobilized and removed | Spring 2026 |
One machine bored both tubes. Between drives it had to be walked back, disassembled to the extent required, inspected, refurbished and relaunched — a roughly six-month operation for a 4,700-ton machine sitting inside an artificial island. Both islands were expanded to receive and handle it.
Run the arithmetic on the advance rate and you get an estimator's lesson. Reported production was around 50 feet per day. Each tube is about 2,440 meters, roughly 8,005 feet. At 50 feet per day that is about 160 production days per tube. The first drive actually took twelve calendar months. The difference is cutterhead interventions, maintenance, segment logistics, holidays, and everything else that is not mining. If you price a tunnel drive off a peak advance rate without a realistic production factor, you will be wrong by a factor of two — and that error scales the same way on every one of the 14 tunnel boring machines currently mining under US cities.
Outfitting: Why "Done Boring" Is Not "Done"
An excavated, lined tunnel is a concrete tube. It is not a road.
Crews are currently building barrier walls and bringing the roadway up to design elevation inside the bore. Beyond that, tunnel outfitting on a modern highway tunnel includes the roadway slab and invert fill, jet fans and the full ventilation system, fire-life-safety systems including detection, suppression and emergency egress, tunnel lighting, power distribution and backup power, communications and radio rebroadcast, variable message signs and lane control, drainage and pump stations, wall finishes, and cross-passage fit-out.
The trade mix inverts completely at this stage. Heavy civil demobilizes; electrical, mechanical, fire protection, controls and finish contractors take over, all working inside a confined 46-foot bore with limited access points and no ability to run parallel crews the way you can on a surface job. Commissioning and integrated systems testing follow, and on a tunnel that testing is not a formality — fire-life-safety systems have to be proven under simulated incident conditions before an owner will accept traffic.
This is why a tunnel can be structurally complete in September 2025 and open in 2027. It is also why the remaining subcontract opportunity on jobs like this is entirely in the electrical, mechanical and systems tiers, which is where crews should be watching the public bid board rather than looking for civil packages that closed years ago.
The $90 Million Incentive and the 18-Month Reset
The commercial story is worth understanding because it explains the dates.
Hampton Roads Connector Partners submitted documentation in the spring of 2022 asserting unforeseen cost and schedule impacts incurred since signing the 2019 contract. VDOT concluded it was in the project's interest to revise the original agreement. The revision reset the schedule — pushing substantial completion back 18 months to February 2027 — and added an early completion incentive.
The incentive is structured around a specific date: to earn the full $90 million, HRCP must reach substantial completion no later than September 25, 2026, which would have represented a delay of only 13 months against the original schedule rather than 18.
As of VDOT's August 2026 updates, substantial completion is scheduled for February 26, 2027, with full completion targeted for spring 2027 and the budget holding at approximately $3.9 billion. Read against the incentive date, that tells you what you need to know about the near-term outcome without anyone having to say it.
There is a broader point here about design-build risk allocation on megaprojects. When a contractor demonstrates impacts it did not price, the owner's realistic options are litigation, a negotiated reset, or both. Virginia chose a reset paired with an incentive — trading schedule certainty for a bounded payment, rather than trading years for a claim. That structure is showing up more often on large design-build work, and it is worth studying if you bid public projects of this scale. Virginia's overall contract volume and concentration are visible in Buildermuse's state construction dashboards.
One small disambiguation for anyone searching: DC Water is running a completely separate tunnel boring machine also named Mary on the Potomac River Tunnel. Two different machines, two different projects, two different owners.
What Opens When
Lane openings are now a recurring event rather than a single milestone. The first westbound traffic shift onto newly widened I-64 in Norfolk was completed on July 27, 2026, moving traffic from Oates Creek to Bay Avenue. Crews have been preparing the 1st View Street and Mason Creek Road bridges for their own shifts, including overhead sign installation. The westbound north trestle is expected to open in the fall of 2026.
The new bored tunnels will carry eastbound traffic once the corridor is complete. Substantial completion is February 26, 2027; VDOT's current public target for full completion is spring 2027.
For contractors, the transferable takeaway is the trade sequencing: on any tunnel, the civil scope ends long before the job does, and the last 18 months belong to systems. For owners, it is the schedule communication problem — every commuter who watched a breakthrough ceremony in September 2025 has spent a year wondering why the tunnel is still closed.
More coverage of federally and state-funded heavy civil work is in Buildermuse's infrastructure section.
