Logan Int'l Builds Concrete Pier Over Boston Harbor to Support Runway Safety Area Extension

Surrounded on three sides by environmentally protected waters, Boston Logan International Airport (BOS) faced formidable challenges when complying with FAA-required runway safety area improvements. 

"Any time someone talks about doing any work in Boston Harbor, it immediately attracts attention," says Stewart Dalzell, deputy director of environmental planning and permitting for airport owner/operator Massachusetts Port Authority (Massport).

The ultimate fix - constructing a concrete deck to support an engineered materials arresting system (EMAS) and other improvements for Runway 33L - cost $80 million and involved nearly a dozen local, state and federal agencies. Associated environmental mitigation expenses accounted for $4 million of the total cost - $2 million in permits alone.  

The FAA funded 75% of the project, covering deck construction and EMAS costs; Massport bore 25% of the total expenses, paying for the pier and associated approach lighting upgrades.

The safety area improvements affected environmental elements that require the highest level of protection for any natural resource in the state, explains Lisa Standley, chief environmental scientist with project consultant Vanasse Hangen Brustlin. The end of Runway 33L, she notes, was built several decades ago near a submerged bed of endangered eelgrass - a critically important plant for fish breeding that supports a wide range of marine life. "Seagrass is in decline everywhere, and the shade that would be created by the runway safety area extension would kill the grass," Standley explains.

"The grass is protected because there isn't a lot of it around the Boston area anymore," adds Carol Lurie, principal with Vanasse Hangen Brustlin. "Handling it must be done carefully, because it is  extremely susceptible to water quality and clarity changes."

The airport experienced similarly serious environmental challenges when it installed its first EMAS to Runway 22R in 2005. That runway is next to a salt marsh that supports the state's soft shell clam industry. Such areas are threatened by any rise in sea level, and therefore can't be altered unless authorities grant a very rare variance, Standley explains. Because commercial clammers harvest shellfish from the area, altering it required mitigation efforts to replace the lost salt marsh and compensate for both the environmental and economic value of the affected shellfish.

Reaching Out

Knowing the Runway 33L project would require myriad signoffs and attract keen interest, Massport officials began meeting with environmental agency representatives in late 2007 to explain the need for runway safety area improvements required by 2015. 

They explained that the FAA and a congressional mandate require safety areas to stop aircraft from undershooting, overshooting or veering off runway edges. Standard dimensions for such safety areas are 1,000 feet long, 500 feet wide. Because Runway 33L abuts Boston Harbor, there simply wasn't land available to add a safety area to the end of the runway. Shortening the runway to gain space for safety enhancements was similarly untenable, because that would have severely reduced the type of aircraft that could use the runway.

Building a standard deck to accommodate the runway safety area wasn't a viable option either, explains Dalzell, because it would have required Massport to add fill materials into the harbor, which would significantly damage aquatic resources. A special pile-supported concrete deck, however, helped avoid such problems. In addition, installing an EMAS provided an equivalent level of safety but required a 600- vs. 1,000-foot long area, explains Kevin Quan, director of sales and marketing for EMAS provider ESCO-Zodiac Aerospace. 

"We looked at our existing natural resources and discussed what we could do to avoid environmental problems and minimize their impact if it came down to that," Dalzell relates.

Mitigation Implications

To mitigate the loss of salt marsh at the end of Runway 22R, Massport is restoring a previously filled marsh a few miles north of Boston. Mitigation for the eelgrass impacted by the Runway 33L project, however, took a more circuitous route. The original plan called for crews to transplant 103,000 shoots of eelgrass to two other locations in Boston Harbor at a cost of more than $500,000. But when much of the grass failed to survive the relocation, as is often the case in the region, a new plan required Massport to create sites two to three times larger for the affected plants farther away from the airport.

While it's always easiest to build a mitigation site right next to the affected area, a remote site was a better fit for BOS, notes Massport Director of Aviation Ed Freni. "These types of coastal resources attract birds and animals," Freni explains. "The last thing the airport wanted to do was attract more of them near the end of its runways."

Currently, the airport is investigating alternative plans that don't involve transplanting, he adds. One possibility involves funding an eco-mooring program that helps protect eelgrass throughout the harbor when boats are anchored in beds of the grass. The strategy involves replacing existing moorings with chains and anchors that float so they don't disturb eelgrass on the seabed during tide and current changes.

Delivery Decisions

The Massport Capital Programs Department, led by Director Sam Sleiman, chose to complete the project via the design-build method because it would facilitate competitive innovation among various marine contractors and expedite construction. Additionally, pile installation could begin as soon as all permits were in place and continue while design of the superstructure was still underway. 

Fay, Spofford & Thorndike managed the project for Massport and developed the bridging documents. "We developed the preliminary design, then took it to the builder for input," says President Peter Howe. "Once construction began, we monitored the project to make sure it was built according to the required design criteria and the operational and environmental constraints outlined in the approved final design."

For years, a wooden pier that extended 2,400 feet from water's edge housed a series of approach lights for Runway 33L. The current project removed that pier and replaced it with a three-acre concrete deck structure that extends 460 feet over the water to support the deck with EMAS. It also added a 1,700-foot concrete pier that was significantly more substantial than the wooden structure it replaced, which was close to the end of its useful life, says Freni. 

Mother Nature recently confirmed the material and engineering choices. "Hurricane Sandy was about as good a test as we could get to verify the soundness of the structure," comments Dalzell. "The deck held up very well against the storm surge."

Navigational aides were also improved, which will facilitate an upgrade in the runway's designation from Category 1 to Category 3, meaning aircraft can land in all weather conditions - down to 600-foot runway visual range visibility. Airport officials expect Runway 33L to be fully operational as a Category 3 by March.

When the upgrade is complete, BOS will have a north-south and an east-west Category 3 runway, notes Dalzell. BOS moved up the list for Category 3 outfitting when airport officials convinced FAA officials to allow them to dovetail the project with the runway safety area enhancements.

Internal Watchdogs

As environmental project managers, Standley and Lurie worked with Massport staff to ensure the safety area enhancements complied with numerous environmental regulations.

"We made sure that the work performed for this project was consistent with what the airport had done in the past," Lurie explains. "We also served as a liaison with state, federal and local agencies to make sure we had a thorough and defensible process for addressing all the environmental issues the project posed."

Massport formed a working group that allowed regulators to weigh in on any jurisdictional issues they had regarding the airport's plan. Officials detailed the scope of the project to ensure that regulators understood the critical safety components it required. They also worked to show that the airport would avoid environmental disruptions and mitigate unavoidable disturbances to get the plan approved.

In some cases, permits required detailed analysis and planning. The Commonwealth of Massachusetts has issued only 30 wetland variance permits in its entire history, Standley explains. Typically, exceptions are granted only for projects, like BOS', that include overriding public safety benefits, she adds.

"This project involved work in a valuable environmental area that has a lot of local concern attached to it," says Lurie. "By bringing all the parties together to come up with a successful strategy to complete the project while protecting the environmental resources, I think we really sped up the approval process.

"Our job was to make sure the approval process didn't get caught up in the red tape of an inter-agency review cycle," she continues. "We accomplished that by having the right people at the right table at the right time."

By involving all pertinent agencies from the beginning, the team saved enormous time by not having to bring individuals up to speed individually. Plus, by giving regulators a chance to participate from the start, BOS secured greater buy-in to the overall project.

"I was surprised how willing the regulators were to come to the table with us," Lurie reflects. "They were very understanding and provided a lot of help in navigating the red tape."

She says FAA personnel, in particular, were "fantastic collaborators." They understood the environmental impact the project entailed, yet were conscious of the airport's budget and the costs associated with such a complicated plan, she explains.

"It was a huge challenge, and the FAA was a close partner in the endeavor," Lurie emphasizes.
The sheer number of agencies charged with protecting natural resources around the airport made the project innately complicated. Although some weren't happy with all aspects of the project, they cooperated because they understood the federal requirements to enhance the runway safety areas, Lurie explains.

Because of the design-build process, Massport secured all of the environmental permits at the preliminary design stage - about 25% completion. As the final design plans developed, minor changes required the airport to go back to the agencies several times to secure approval for the updated plans. Getting new plans approved was much easier because of the open communication airport staff had established with the agencies, notes Lurie.

One concern that arose mid-project involved the effects of disturbing silt on the ocean floor. To prevent harmful consequences in the harbor, workers installed a curtain that floated on the water to contain the silt within the construction area.

Now's the Time

BOS officials had wanted to extend the safety area for Runway 33L for years, but environmental concerns and a lack of available land prevented it. But once the FAA approved EMAS systems, equivalent safety standards could be achieved with shorter pier over Boston Harbor. BOS became one of the industry's early adopters when it installed its first EMAS system on Runway 22R in 2005. Upon completion, officials felt EMAS could be the ideal solution to the east-west Runway 33L, as well.
Massport's Engineering Project Manager Peter Austin notes that through close collaboration with the FAA, the airport was also able to reduce the width of the structure from the usual 500 feet to 300 feet, and still provide an equivalent level of safety.

"It was a pretty sizable project - one of the largest we have ever done," says Quan.

Constructing the EMAS required a 300-by-460-foot cement pad to be constructed starting 94 feet from the runway end. The deck had to be long and strong enough to stop a fully loaded Boeing 747 traveling at about 70 miles per hour.

After the deck was built, crews installed 125 rows and 44 columns of precast concrete blocks ranging in thickness from 6 to 26 inches. Once installed, some of the blocks were cored to accommodate 75 approach lights that would be permanently mounted in the EMAS bed.

All 5,500 blocks include jet blast protection and a durability coating to ensure a long life, notes Quan. After the blocks were trucked in from New Jersey, a forklift positioned each one into a specific location on the pad according to a grid drawn on the pavement showing the block size and its unique number.
Because the deck would shift slightly with tides, expansion joints were included to allow the concrete to move without cracking. The EMAS blocks sit on a plastic plate that moves as the concrete expands and contracts.

Even though project contractor J.F. White had never installed an EMAS system, its crews took only three weeks to install the blocks - a task Quan considers "exceptional."

Airport officials were also impressed with the feat, and with the EMAS' ability to crumble into gravel if an aircraft rolls over it. "Had this structure been installed in 1982, it would have stopped the World Airways jet that slid off the runway that winter and into the harbor," reflects Freni. "This system would have stopped that aircraft, and we strongly believe it will prevent a similar incident from happening again."

While We're At It

BOS saved time and money by repaving the entire length of Runway 33L when it was already shut down for safety area improvements, notes Dalzell. Previously, officials opted to split the 10,000-foot job over two years. But with the entire repaving complete, operations on the runway won't be impacted for many years to come. "(That) reduces the level of inconvenience our passengers and airlines need to experience," says Freni.

The project used warm-mix asphalt, which BOS pioneered the use of a few years ago on a different runway. The warm-mix product is environmentally friendly because it heats at a lower temperature and consequently reduces emissions and saves energy, Freni explains.

"The warm mix is safer and healthier for workers to use, and it is just as durable as the hot-mix asphalt we have used in the past," he notes. "Not only is it good for airport operations, it was a good benefit for the community. The fewer times we need to shut down a runway and divert aircraft, the better it is for the community."

BOS took advantage of a similar opportunity to group improvement projects last year, when crews installed LED lights in the parking garage at Terminal B while it was shut down for repaving.

Moving Target

Given its coastal location, BOS is often at the mercy of changing weather. During summer, prevailing winds typically favor use of the north-south runway. But when winter arrives, winds can shift overnight to the northeast. Consequently, the east-west runway needed to be ready for winter traffic by Oct. 1.

Environmental laws, however, prevented construction until after July 1, because the harbor is a spawning area for winter flounder. In addition, agreements designed to minimize noise disruptions for nearby neighborhoods restrict the time crews can work to weekdays from 7 a.m. to 7 p.m.; allowable work slots on weekends are even slimmer, notes Austin.

Because BOS officials are keenly aware of how well sound travels across water, they worked closely with contractors to reduce the noise associated with the project. One of the most innovative strategies was using concrete pilings instead of steel.

"Using concrete helped because we didn't have the noise associated with steel equipment pounding steel pilings into the bedrock," explains Dalzell. "We also buffered the equipment in a way that neighbors weren't bothered by constant pounding. In fact, we had very few, if any, comments about project noise from our neighbors."

Further complicating matters, Runway 15R-33L is BOS' noise abatement runway, so it is the preferred runway for nighttime departures and arrivals over the harbor. That meant crews could only work on the runway between 7 a.m. and 7 p.m. from May until July, Austin explains. At the end of each 12-hour window, they had to move the cranes and barges so the runway could be used that night. 

Once July 1 arrived and the environmental restrictions against working in the water passed, the runway was closed for three months and larger cranes and pile drivers were used. Work hours had to remain the same (7 a.m. to 7 p.m.), but the cranes did not need to be lowered every day. 

At the end of the three-month runway closure, the work schedule reverted back to the 7 a.m. to 7 p.m. routine and workers, materials and equipment had to be moved each night once again.

"There were so many issues that came into play with this project that timing of each stage was critical," Howe says. "Noise mitigation prevented planes from going over neighborhoods during certain hours. Environmental mitigation prevented work from taking place between Feb. 1 and July 1 to protect hatching fish eggs. And weather conditions required the runway be open by Oct. 1 to accommodate winter winds."

All those conditions gave the airport a very narrow window over two seasons in which to complete the project, adds Dalzell.

"A federal executive order required the airport to create a longer runway safety area by a specific time," Lurie explains. "Not only did we have to figure out how to protect many important natural resources before the project could begin, we had to keep one of the nation's largest airports operating while construction was underway."

Material delivery and logistics also proved to be crucial factors. To save time, money and fuel, and to avoid local roadway congestion, crews used barges to bring in and store supplies for the project. But active marine traffic in Boston Harbor made scheduling deliveries no easy matter. 

Rewarding Results

"This was an extraordinarily challenging environmental project with many moving parts operating on a very fast timeline," summarizes Standley.

Airport officials, however, are pleased with the results. "The project turned out to be everything we expected," says Freni. "We turned a wooden pier into a concrete pier. We did not have to shorten our runway to get the safety area completed. In fact, we took advantage of the plan to upgrade the runway to a Category 3 instrument landing system, which now gives us redundancy to land at two runways with minimal visibility.

"It required tremendous coordination between our capital programs group, aviation operations, contractors, environmental agencies, airlines and the community," he adds. "But, by doing so, we kept the project on time and on budget."

The size and scope of the project was "simply amazing," Freni concludes.

"In the end, we have a good, solid runway, and we won't need to do any major work on it for years."