BY: Mike Chalmers

Encompassing well over seven million man-hours to date, the Hampton Roads Bridge-Tunnel (HRBT) Expansion is the largest highway construction project in Virginia’s history.

[Photo above: Lowering the cutterhead into the launch shaft for attachment to “Mary” the tunnel boring machine. Photo courtesy Virginia Department of Transportation.]

This transformative undertaking will widen the current four-lane segments along nearly ten miles of the Interstate 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. Including the construction contract and owner’s costs, the project’s total budget is over $3.9 billion, making it one of the largest infrastructure projects in the country.

Open since 1957, the initial Hampton Roads Bridge-Tunnel replaced a ferry service, but traffic quickly outpaced projections by tens of thousands. To date, the 3.5-mile crossing consists of two two-lane immersed-tube tunnels on artificial islands, with trestle bridges to shore, connecting the cities of Hampton and Norfolk—in the center of a region whose population has grown to nearly two million people, presenting all the traffic headaches and multi-mile backups that one might expect.

Geographically, the HRBT is hardly the only significant water crossing in Eastern Virginia, but it is certainly the most critical to the metropolitan region variously known as Hampton Roads, Tidewater, “the 757”, or Virginia Beach-Norfolk-Newport News in the ungainly phrasing of the U.S. Census. The census includes ten independent cities and all or part of nine counties in the metropolitan expanse. Notably, while several other major U.S. Highways serve the area, I-64 westbound is the only Interstate (or limited-access) highway by which one may exit the region, placing a great deal of pressure on this single corridor.

The Expansion project now underway will add a third lane and a part-time drivable shoulder to I-64 in each direction and a new pair of bored tunnels that will increase capacity from the current four tunnel lanes to eight. Altogether, the work will involve 9.9 miles of interstate widening and 3.5 miles of combined trestle and tunnel, expanding the crossing from the current four lanes to six lanes on land and eight lanes over and under the water.

Numerous variants of the HRBT Expansion project have been studied and proposed over the past 30 years. In 1992, the Virginia General Assembly passed a resolution directing the Virginia Department of Transportation (VDOT) to conduct a study of congestion at the HRBT. The study concluded that short-term measures would not solve congestion at the HRBT and that a long-term, large-scale solution would be required.

Multiple environmental studies and procurement efforts followed, evaluating a range of highway alternatives for a new crossing of the Virginia harbor. While there were initial delays due to funding constraints, the necessary studies resumed over time and allowed the project to move forward.

With funding and key environmental approvals in place by June 2017, VDOT began the design-build procurement for the HRBT Expansion, issuing a Request for Qualifications in late 2017 and a Request for Proposals (RFP) to the shortlisted offerors in mid-2018. In April 2019, the design-build contract (Comprehensive Agreement) was executed.

Ultimately, VDOT is the owner of the project, while a design-build team, the Hampton Roads Connector Partners (HRCP), is building the project. HRCP consists of four companies as a construction joint venture: Dragados USA, Vinci Construction, Flatiron Constructors, and Dodin Campenon Bernard. The lead engineers, HDR and Mott MacDonald, are employed by HRCP as a design joint venture.

To that end, in addition to VDOT and the Federal Highway Administration, as well as the above-mentioned partners, the HRBT Expansion project comprises a comprehensive listing of both cooperating and participating agencies, federal partnering agencies, scoping agencies, historic preservation consulting parties, and a stakeholders committee consisting of key community, military, industry, and maritime leaders.

Method Selection

“During the project’s development phase, many of the technical scoping, environmental, procurement, and stakeholder-outreach activities moved forward in parallel,” explained HRBT Expansion Project Director, Ryan Banas.

Banas also pointed out that, due to the cost of the project’s scope, VDOT initially considered segmenting the work into smaller contracts in order to attract certain bidders, but the Department ultimately determined to procure the scope as a single contract due to the complexities of coordinating interfaces between multiple contracts while safely maintaining high volumes of live interstate traffic.

The result on the ground (as of March 2023) equals 930 pieces of equipment, including 6 crew-transport busses, 8 wheel loaders, 14 mini-excavators, 20 excavators, 29 forklifts, 36 boats/barges, 38 cranes, 41 manlifts, 66 generators, 126 light plants, and 230 on-road vehicles. And, of course, the star of the show—the $70 million tunnel boring machine (TBM) being used to bore the twin tunnels next to the existing Hampton Roads Bridge-Tunnel.

“The TBM is currently at work, excavating about 1.5 miles from the HRBT South Island to the North Island,” noted Banas. “After mining this first tunnel, which is expected to take about a year, the machine components will individually be turned around at the North Island, which will take about six months. It will then spend another year digging from the North Island back to the South Island to form the second tunnel.”

Following excavation, he added, the tunnel interior fit-out work—with construction of the roadway elements, tunnel utilities, and systems—will finally occur before the tunnel is opened to the traveling public.

“Mary the TBM,” as she was ultimately named in 2020 through a naming contest open to middle school students in Hampton Roads, landed in Virginia by way of a contract that HRCP awarded to Herrenknecht of Germany.

But even before Mary arrived, VDOT had initially assumed the new HRBT would be an immersed-tube tunnel. However, the Department ended up giving proposers the option to select the method they believed was best suited to project conditions and proposers’ individual strengths.

VDOT’s concept design was silent regarding tunneling approach, and the RFP contained performance-based specifications that accommodated both immersed-tube and bored tunneling methods. After proposers were instructed to evaluate the available information and declare their chosen method in July 2018, two remaining proposers indicated they’d decided on the a bored-tunneling approach. VDOT then amended the RFP to move forward with this method, accordingly.

“In the RFP, VDOT provided general performance requirements for the project’s TBM but left the selection of its manufacturer as well as the selection of machine type—earth pressure balance (EPB) or slurry TBM—to the design-build contractor as part of their means and methods for tunneling in soft ground,” Banas indicated.

“During the procurement, HRCP considered multiple TBM options and manufacturers, taking into account the extensive subsurface information that VDOT provided in the reference data library. Ultimately, HRCP chose a variable-density TBM from Herren­knecht due to its ability to address a wide range of soil types and subsurface conditions. This type of TBM excavates material via a hydraulic slurry circuit, with slurry properties that can be continuously adjusted for site conditions. At forty-six feet (fourteen meters) in diameter, this machine is Herrenknecht’s largest variable-density TBM to date, as well as the second largest TBM used for a transportation tube.”

Walking the Load

After factory-acceptance testing of the TBM at Herrenknecht’s plant in Germany in 2021, the machine was disassembled and shipped across the Atlantic in 170 containers and pallets. It was then reassembled in the launch shaft (a pit over 70 feet deep and larger than a football field) on the HRBT South Island during 2022 and into 2023. Nearly 120,000 cubic yards of soil was excavated from the launch pit, which would fill up Norfolk’s Harbor Park Stadium (Norfolk Tides minor league baseball team) to a depth of over eight feet. Moreover, the amount of concrete used in the pit would fill up 16 Olympic swimming pools.

That said, the size of most components involved conventional lifts, but several components were large enough to require particularly specialized lifting plans.

“The heaviest pick on the HRBT project overall involved lifting the TBM cutterhead after its individually shipped components were welded together on the South Island,” said Banas, adding that the fully assembled cutterhead weighed 469 tons, and with all rigging (including a 6.5-ton spreader bar from Herrenknecht), the total boom-tip load for the main crane was 498.5 tons.

“For this pick, the cutterhead was tilted up from its initially horizontal position by a tandem lift, using a Manitowoc MLC650 main crane and a Manitowoc MLC300 tail crane. The MLC650 main crane [Series 3 VPC Max] was configured with a 164-foot main boom, over 440 tons of counterweight, and a 26-part line. Once the cutterhead was tilted upright, the tail crane was disconnected, and the main crane walked the load toward the launch shaft and lowered the cutterhead into the shaft to be bolted to the main drive of the TBM.”

In addition to the cutterhead pick, another complex lift, according to Banas, involved the TBM tail skin, also performed with the MLC650 main crane and MLC300 tail crane.

“The tail skin was essentially a 46-foot-diameter steel can, just over 15 feet tall. Although this load weighed considerably less than the cutterhead, totaling around 210 tons with rigging, the tail skin had to be tilted upright and then set in precise alignment with the 4.5 percent downhill slope matching the TBM’s starting angle.

“For this lift, Enerpac SyncHoist cylinders—each manually controlled, with 110-ton capacity and 1.5-meter stroke—were included in three of the four main-crane rigging legs to enable fine adjustment of the orientation of the tail skin during its installation.”

Particular Relevance

Providing additional support on the tunnel preparation was a gantry crane supplied by GH Cranes & Components—which loaded segments from the barge or storage platform onto multi-service vehicles (MSVs) supplying the TBM. The crane, designed for offshore weather conditions as well, was in operation 24/7, and boasted a lifting capacity of 44 tons.

Originally, the cycle-time analysis suggested that gantry-crane operations could become a potential chokepoint for the project, so the crane’s runway (rail) was improved during the design phase by extending its range from over the shaft and the storage platform up to the end of the barge slip. The modification made it possible to supply the TBM directly with elements recently arrived by barge, which ultimately reduced the overall number of lifting operations by bypassing the intermediate step of placement in the storage area. Further, the overhang of the crane on the north side allowed for the transfer of materials between the shaft and the surface.

Banas stressed that the presence of the gantry crane also serves to spotlight the family of additional machines in operation throughout the site and within the full scope of the project.

“Although much attention has understandably been focused on the project’s shaft and tunnel construction, the HRBT Expansion scope also includes over a billion dollars of highway widening, land bridge, and marine bridge work,” he emphasized. “The marine construction activities require an extensive fleet of barge-mounted cranes. Several of these are Manitowoc and American ringer cranes, whose capacity is necessary to set the precast concrete bulb-tee girders—which range up to 85 and 124 feet long.”

This marine fleet, he added, is also kept busy driving a thousand 54-foot-diameter concrete cylinder piles for the new bridges, as well as placing precast concrete caps atop these pile foundations.

“Where the water is too shallow to accommodate floating cranes, HRCP has built temporary steel work trestles from the shoreline to provide crane access for driving piles, placing caps, and setting girders,” said Banas. “These trestles also provide isolation from the local waves and currents, which are otherwise significant considerations for designing crane lifts in a marine environment.”

As far as risk management goes across this vast worksite, Banas also noted that, while everything is on pace for completion, one element with particular relevance for crane operations is the potential impact of hurricanes—given the coastal location of the bridge-tunnel.

“Even though the project has experienced minimal impacts to date from severe weather, a windstorm can generate strong waves that cause significant impact on marine operations, and floating cranes need to be brought to safe harbor well before a hurricane’s arrival,” he acknowledged. “To help keep the equipment safe, HRCP has designated a sheltered harbor area with numerous mooring piles, where floating cranes and material barges can be secured in advance of potential severe weather.”

Progress being what it is, “Mary the TBM” began excavating on April 24, 2023—weighing in, along with its gantries, at a whopping 8.3 million pounds. Much of the tunneling, at a rate of 50 feet per day, will take place within a firm layer of soil known as the Yorktown layer—with the new tunnels taking shape up to 50 feet deeper than the current tunnels.

And because TBM tunneling is on the project’s critical path, the project’s completion date is closely dependent on underground conditions and TBM performance.

“The design, construction, and delivery of a project of this magnitude is detailed and complex,” confirmed Banas. “The contract completion date remains November 2025. However, we are aware that the contractor has fallen behind schedule by approximately eighteen months. With that in mind, VDOT continues to monitor work with the contractor to achieve critical project milestones.”

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This article appeared in the May/June 2023 issue of Wire Rope Exchange.

To learn more about this project, including extensive photo and video resources, visit their website at www.hrbtexpansion.org