The project team understood at the outset the inherent challenges of carrying out construction within the confines of a busy airport. But last year’s emergence of a global pandemic added multiple dimensions of uncertainty, challenging the team to find ways to ensure operational efficiency.

Midway through 2021, the concourse is already in operation, having staged a “soft opening” three months ahead of schedule. The checkpoints are on pace to be completed this fall.

Passenger volume through the airport fell to 35,000 in April 2020 from slightly more than 1 million in March 2020. It is still below pre-pandemic levels but has climbed steadily, reaching 299,000 as of March of this year.

Metropolitan Washington Airports Authority construction program manager Ryan Wolfgang says that achieving those milestones amid so many figurative headwinds and unexpected issues is a credit to collaboration among his agency, the joint venture design team of PGAL and AECOM and lead contractor Turner Construction.

Wolfgang notes that Turner’s construction manager at-risk contract “allowed us to issue preconstruction task orders as the project progressed and phase terminal work to minimize potential disruptive effects to airside operations.”

That was particularly true for the three-level concourse, which is to replace the airport’s notorious Gate 35X—essentially a bus stop for shuttles that transported passengers to and from 14 outdoor tarmac gates, or hardstands.

Preserving this multimodal shuttle activity throughout construction involved scheduling the initial step of compressing the site’s decades-old fill with more than 41,000 cu yd of surcharge. The two-phase process spanned a 102,500-sq-ft area that included portions of the airside apron.

Because excessive settlement in portions of the initial phase threatened to delay concourse foundation work, the project team quickly revised the surcharge plan by also creating a 10-ft-high, 26,000-sq-ft berm to facilitate construction crane staging.

“That helped us advance work on the concourse while also providing sufficient time to mitigate all the geotechnical issues,” explains Shimelis Meskellie, authority manager for that phase of the project.

To accommodate a saturated subgrade that included scattered pockets of clay, the terminal’s foundation includes 440 12-sq-in. driven precast piles and 239 18-in.-dia augered cast piles, linked with 130 pile caps and interconnecting grade beams. Priyam S. Shah, the authority concourse project manager, says maintaining each pile’s exact location as it was driven to full depth had to be carefully choreographed and monitored. “That was a big challenge for the contractor,” Shah says.

One of the biggest obstacles in the concourse’s path was the most immovable—an existing 4,200-sq-ft electrical substation with an exterior transformer yard that served the airport’s two primary terminals.

PGAL project manager Dennis Comiskey explains that because no concourse configuration could fully bypass the obstruction without reducing the number of gates, “we essentially built through the substation by incorporating it into the footprint.”

While that plan was feasible from a construction standpoint, the project team had to ensure that the substation stayed fully operational while removing the upper 10 ft of the structure to align with the concourse’s floor plates. The solution, Comiskey says, was to develop a structural framing strategy “to encapsulate the substation and provide sufficient clearances without creating an impossible situation to build the surrounding concourse.”

Encasing the substation with heavy-duty plastic sheets and wooden frames, Turner added a temporary waterproof platform across the interior that protected the electrical equipment during removal of the original walls and roof sections. Separate interior enclosures and scaffolding systems protected individual switchgear as a gantry crane placed 64-ft-long floor beams across the top. An array of conditioning units maintained positive pressure around the switchgear, minimizing the potential of humidity-induced arc flashes.

The substation itself can be accessed from outside for maintenance. The concourse interior above the encapsulated facility is used as back-of-house space for concessionaires.

Paul Angelini, Turner general superintendent, says the extensive planning paid off in a “pretty seamless” process that required only a few weeks to complete. “We worked around a living, breathing substation, with no incidents or safety issues,” he says.

 

Coping with COVID-19

While extensive planning was crucial in executing Project Journey’s initial years of construction, adaptability proved to be the watchword for 2020 as the pandemic upended jobsite practices and the air travel patterns that the facilities were built to support.

With flight cutbacks reducing the number of Gate 35X hardstands, the project team saw that it could accelerate installation of a 1,020-ft-long extension of an underground hydrant system used to fuel aircraft. That cut the originally planned year-long task by nearly half.

The pandemic-driven cutback in airline traffic also altered Turner’s approach to the two new security checkpoint buildings. They will expand screening capacity, alleviate congestion and provide flexibility for implementing future security technology and protocols.

Wedged between the airport’s Metrorail station and above existing terminal roads and pedestrian bridges, the buildings are founded on a total of 247 augered cast piles plus additional support columns installed on the existing arrivals levels. The resulting “floating” structural system provides clearance for emergency vehicles and isolates the new checkpoints from existing infrastructure foundations.

Constructing the building over existing terminal access roads brought the added consideration of safeguarding passengers. Jeff Klinger, Turner vice president and construction executive, says those people were “essentially walking through a construction site.” Dust walls and other measures could isolate pedestrians from adjacent building activity, but maintaining vehicle traffic beneath the checkpoints further complicated both safety and scheduling.

“Unlike other projects, if a trade can’t work in a certain area, you can’t have them just go work on another elevation or outside,” Klinger adds.

For that reason, most of the checkpoints’ construction activity initially took place at night. As with the terminal fueling system, the pandemic-driven drop in passengers allowed more work to be shifted to daytime hours. Though the move allowed Turner to nearly triple its onsite workforce, more people on site meant greater potential exposure to COVID-19.

“It was a lesson in ‘be careful what you wish for,’” says Vito Perrotta, Turner construction executive. Along with implementing a variety of safety measures to prevent virus spread without compromising worker productivity, Perrotta says a forced shift to online video meetings provided an unexpected boost to the project-wide communication.

“Before, we would just send emails,” he recalls. The improved coordination from having everyone together for a video “was pretty powerful.”

Pandemic-related disruptions to material supply chains also forced Turner to abandon just-in-time delivery to accumulate components whenever possible, staging them in warehouses and any available open space on the airport site.

Of particular concern was steel coming from a fabricator in Canada for the buildings’ distinctive curved roofs. Turner learned early in the pandemic that the border with Canada might soon be closed and worked with the fabricator to accelerate shipments to a storage yard in southern Virginia.

“I think the last load got out just in time,” Perrotta says with a laugh.

In recent months, contractors have fitted each building with 580 panels of electrochromic glass to compensate for changing daylight conditions. The structures are topped with a continuous curved roofline that echoes the Cesar Pelli-designed Terminal B/C, built during the airport’s last major facilities upgrade in 1997.

Project Journey at press time was nearing its end as the team applied interior finishes and worked on space fit-outs. Wolfson says the experience has offered valuable lessons in resiliency and adaptation. “With COVID, the first order of business was of course to make sure the workforce was safe, particularly as it grew,”  he says.

Wolfson adds that although some workers did test positive over the course of the project, “there was never a case where we lost entire crews. In the end, we were able to work through without shutting the project down.”