Kodiak Benny Benson State Airport (ADQ) faced a quandary when devising plans to meet the federal mandate for runway safety areas: There simply wasn’t enough land at the island-bound Alaskan facility to add them. So planners got creative and built into the ocean.
Contractors moved an estimated 1.1 million tons of rock to fill a portion of the Gulf of Alaska in order to create enough surface area for an engineered material arresting system (EMAS) on one runway and to lengthen another runway to allow for an EMAS bed on its other end.
Project: Runway Safety Areas
Location: Kodiak (AK) Benny Benson State Airport
Cost: $59 million
Funding: FAA, Alaska Dept. of Transportation & Public Facilities
Unique Challenge/Strategy: Build extension into Gulf of Alaska
Rock Moved: 1.1 million tons
Environmental Impact Study: Mead & Hunt
Project Manager: Kiewit Infrastructure West Co.
Engineered Material Arresting Systems: Zodiac Arresting Systems (Zodiac Aerospace)
Prime Consultant: HDR Inc.
Concrete Armor Units: Core-loc, by Concrete Technology Corp.
The $59 million project, which took 18 months to complete, was paid for by the FAA and Alaska Department of Transportation and Public Facilities. Construction ended in October 2015, in time to satisfy the end-of-year federal requirement.
“The successful completion of the project gives us an overshoot, so if a plane is landing on the runway and can’t stop, the [runway safety area] will now stop it without damaging the aircraft or causing injury to passengers,” explains Robert M. Greene, superintendent of the Kodiak Aleutian district agency that manages the airport. “Departing aircraft are also aided by this,” he adds. “If there is a problem on takeoff and the pilots can’t get airborne, they can keep the plane on the ground and stop it without significant damage.”
Although 90% of the airport’s traffic is general aviation, ADQ is also served by two commercial carriers: Alaska Airlines and Ravn Alaska, a regional airline. The U.S. Coast Guard operates C-130 aircraft at the airport as well.
The ends of runways 26 and 1 were extended about 600 feet into the water, where the average depth at high tide ranges from 13 to 15 feet. EMAS beds were then installed on the end of Runway 26 and at the 19 end of Runway 1-19.
The project presented significant logistical challenges for Kiewit Infrastructure West, the firm that managed the project, because materials and equipment had to be transported via barge to the remote island, often in inclement weather.
“When any big storms came in, the barges would get delayed,” recalls Kiewit Infrastructure West Project Manager Dustin Lehman. “And we got a lot of rain in Kodiak.”
The Kiewit team drilled and blasted rock from a nearby quarry, then trucked the material about four miles to the airport. Drilling and blasting were limited to daytime hours to minimize noise, and hauling and filling work was completed at night to minimize disruptions to airfield operations.
About 20 trucks, each capable of carrying 25 tons, were used for the process. Some had to be barged in from Anchorage. “You could see progress every day because we were hauling between 8,000 and 12,000 tons of rock a day,” relates Lehman.
Natural armor stones, each weighing about 12,000 pounds, were positioned to prevent the fill from shifting after it was installed. Core-loc engineered units, which provide substantially more support because they lock together, were also used at the end of Runway 26 to provide additional protection from sea current and wave action, Lehman explains.
Procuring the armor rock was an effort in itself. Kiewit mined the large rocks from the Wrangell Harbor Quarry in southeast Alaska and then barged the pieces 800 nautical miles across the Gulf of Alaska to Kodiak.
Environmental factors restricted when certain phases could be completed. The Alaska Department of Transportation, which oversaw the project, prohibited in-water work between April 1 and July 15 to protect local aquatic species.
“We were working in an area directly adjacent to the mouth of the Buskin River, which is a critical salmon habitat,” notes Merle Sena, project engineer for the state transportation department. “We were also filling into Women’s Bay, which is home to several species of protected wildlife — killer whales, sea lions, seals, otters and bald eagles.”
After all the rock was in place, crews added a layer of aggregate to cap the surface. Electrical infrastructure was installed for runway lighting, edge lighting, taxi lights and signage. Then, the area was paved to runway specifications to allow for the EMAS installation.
Location, Location, Location
Zodiac Arresting Systems, which fabricated the EMAS blocks and supervised their installation, was also affected by challenges inherent to the ADQ jobsite. “It was a dramatic project and it was a pretty good logistical challenge to get the pieces of our system shipped to the island,” recalls Hugh K. DeLong III, the company’s EMAS airport civil engineering officer. “We had a combination of trucking, rail and barges going up the protected passageway out of Seattle to get to Kodiak.”
Although Zodiac had previous experience designing EMAS beds for installation over water, the project at ADQ was the first built over an ocean. “HDR, our prime engineering team, had to deal with and resist some real heavy-duty forces out there,” notes DeLong. “Part of the challenge was dealing with the close proximity to winter wave action from storms.”
The EMAS bed on Runway 19, which sits about 35 feet from the end of the runway, includes about 2,100 blocks and is designed to provide at least 40 knots of stopping power for aircraft. The EMAS bed on Runway 26 sits about 250 feet from the end of the runway, contains about 2,300 blocks and provides 70 knots of stopping power.
“EMAS is always at the end of the available space; so if you overrun, the aircraft can get stopped before you go into the EMAS,” DeLong explains. “There can be substantial economies for this because you’re not damaging an EMAS system and you’re probably not damaging the aircraft either. With Runway 26, we set the bed back further so the airplane has an opportunity after passing the end of the runway to decelerate itself before getting into a true emergency condition where [pilots] have to rely upon the arrestor to get stopped.”
Kiewit crews installed both EMAS beds in about three weeks.
Having managed other projects for the Alaska Department of Transportation, Sena knew that weather would play a considerable role throughout the project. “Kodiak is notorious for lots of rain and lots of wind,” he comments. “Being on the southeastern coastline of an island in the Gulf of Alaska means we see strong storms and significant tides. It was a constant challenge to maintain our shoreline protection measures to ensure our fill material did not get washed away during times of heavy storm surge or extreme tides. And we were always working with all affected parties so that we could adjust our operations to minimize any impact on U.S. Coast Guard operations, the air carriers and the traveling public.”
Just in Case
During more than 25 years at the airport, Greene recalls two instances when he wished ADQ had runway safety areas in place.
In the first case, a Boeing 737 did not slow fast enough, so the pilot ran the aircraft into the snow to stop it. “After that incident, I realized that if the plane would have gone off into the ocean, the aircraft would probably have been destroyed and someone would have been hurt,” Greene relates.
The second involved a 737 that lost an engine during takeoff. “The pilot knew he didn’t have time to stop because the plane would have gone off the runway and into the ocean,” Greene explains. “So they chose to take it airborne, turned it around and then made an emergency landing—all of which could have turned out bad.”
With ADQ’s recent project complete, pilots now have more options at their disposal, he reflects. “If there is a problem and they can’t get airborne, they can keep it on the ground and stop without damaging the aircraft.”