Technical Description:
• 1,000,000 sf of ArmorFlex
® Class 40TSS Mats
![]()
Twenty years after the Harrisburg International Airport (HIA) began working on plans to repair and rehabilitate a levee built by the United States Army Corps of Engineers to prevent flooding from the nearby Susquehanna River, the project came to fruition. The 13,000' long earthen structure runs along the west side of the airport's runway and was eroding due to excessive vegetation, burrowing animals and damage from ice jams and other heavy debris.
“It hadn't reached the point where it threatened the integrity of our runway and other critical infrastructure, but we knew it ultimately would reach that point without rehabilitation,” stated Tim Edwards, Executive Director at HIA. "We basically had a repair project fully designed in 2004, but there was no funding available from the FAA at the time."
In 2018, funding became available and since HIA met the requirements, they were granted a $20.2 million grant in May 2019. Additional funds were provided by the state of Pennsylvania and Susquehanna Area Regional Airport Authority, the airport's owner.
Urban Engineers Inc. had designed the project years ago and provided the final design which included 1,000,000 sf of ArmorFlex® Class 40TSS Mats in various sizes. ArmorFlex is a flexible, interlocking matrix of cellular concrete blocks of uniform size, shape, and weight used for erosion control. ArmorFlex systems have specific, tested, hydraulic capacities and are laced longitudinally with revetment cables to provide ease-of-handling and rapid installation. The mats were selected over riprap for the cost effectiveness, ease of installation and the ability to prevent erosion, vegetation growth and damage from animals burrowing.
During the project, crews from KC Construction Co. (KC) used large excavators with spreader-bar attachments to install about 6,700 mats, or about 130-140 each day. "We believe this is the largest articulated concrete block project in the country," said Bob Machiesky, On-Site Project Manager/Superintendent for KC. Concrete was poured into the horizontal gaps between the mats to grout them together. Next, a skid-steer loader was outfitted with a cylindrical broom attachment to fill the block openings as well as the vertical gaps with the same kind of stone used in the base layer. In order to get out of potential high-water zones as quickly as possible, KC began installing the mats at the bottom of the levee, working upward and away from the water.
During construction, it was imperative for the construction crews to communicate with air traffic controllers, especially while working in restricted areas due to the risk of the equipment interfering with the localizer and glide slope systems. With the grade of the slope ranging from 33-50%, installation can be a bit tricky but experienced installers completed the job effectively, efficiently and six months ahead of schedule. ArmorFlex proved to be a great solution for the site.
“Overall, on a scale of one to 10, I'd give the project a 10,” concluded Brian Peda, Deputy Practice Leader/Construction Engineer with Urban Engineers. "Everything went pretty smoothly and according to plan."
Technical Description:
• 1,000,000 sf of ArmorFlex
® Class 40TSS Mats
![]()