Regional airports are very often the lifesaving link for residents in geographically challenging locations such as the mountains of West Virginia and rural, snowy New England. The Rutland Southern Vermont Regional Airport is one such facility. It has limited service but is an essential transportation link that brings the region together with connecting flights to Boston’s Logan Airport.
According to Tim Herbert, however, the one incoming runway needed an extension and an engineered materials arresting system (EMAS). “The Federal Aviation Administration had put out a mandate that by the end of 2015, airports in limited-space environments whose planes might overshoot the end of the runway must install an EMAS,” explains Herbert, a superintendent with Markowski Excavating in Vermont. “This is basically like a truck runaway ramp except it’s for planes. In the case of Rutland, the grade at the end of the property drops into a gorge, so they really needed this protection to avert any disasters.”
The finished size of the EMAS needed to be 141 feet by 268 feet. But installing the system involves so much more than just throwing down some gravel to slow an aircraft, even a small one that is typical of Rutland’s day-to-day aviation equipment.
“We have one commuter passenger carrier that goes to Logan, and of course the military and Fedex use Rutland, and it really caters to small private jets. To be in compliance with the FAA, we needed to create a rise in elevation, support that with retaining walls, and then build the EMAS. That structure is composed of friable concrete, so in the event of an emergency the aircraft landing gear will shatter the pad, and then the plane will stop.” The retaining walls were constructed of blocks from Stone Strong Systems, produced by Gilbert Block in New Hampshire to help meet the critical deadline.
The Vermont Department of Transportation owns the airport; the project was funded mainly with federal money, and “the state matches 10%,” says Herbert. Because the original low bidder on the project defaulted, however, the award to Markowski Excavating came with a compressed timeline, so the company had to work quickly to make the December 31 deadline. That meant working in very cold temperatures, with a full crew, heavy equipment, and deliveries and spoils removal all on an agenda that had to run like clockwork. Gilbert Block began making the 1,600 blocks needed for the project in November to meet the April construction start date.
“It took us all winter to prepare the stone base and install the drainage system, which involved removing about 40,000 cubic yards of material and replacing it with a suitable aggregate that we have in our yard. However, even before starting we had to find a site to dump the material. The Town of Clarendon helped us find a location, and then we used the excess to create a new athletic field that is essentially a recreation field coming at no cost to the taxpayers.
After replacing the unsuitable material with 3-inch stone, “we then started constructing the walls with the Stone Strong Systems block. It was a two-wall system; one wall went up 33 feet vertically, and the second wall stepped back 50 feet, then went up another 28 feet,” he explains.
Behind the first retaining wall there was a 2-inch minus sand cushion for drainage, and behind that, a 5-inch structural burrow that created the base for the second retaining wall.
“These are big blocks and weigh about 3 tons each, measuring three feet by eight feet, which is pretty impressive,” says Herbert. “The stones do interlock, the top having cast-in-place steel hoops, and the bottom fits into a shell with geogrid wrapped through it for stabilization. We add ¾-inch stone to infill the voids and lock the blocks together.”
The walls were 790 feet long. To ensure that grade increase and fill amounts were correct, “we used a GPS automated dozer, which helped place gravels, sand, and topsoil and do all finish grading without the use of complete survey crews,” he says. “We had to make sure that for every row of geogrid, the correct 2-inch minus sand cushion was behind it.”
Herbert says it was a “very effective and smooth system to create the wall. Once you got the hang of it, it went very fast. We built these two walls in three months. The DOT loved it and aviation people were really happy.”
He adds, “This block has performed very well for us. It’s beautiful looking and creates an attractive impression, so I would definitely recommend Stone Strong for any big commercial or industrial project where performance and aesthetics are your goal.”
As further affirmation of the project’s success, Markowski was awarded the Best Builders Award from the American General Contractors, Vermont Division, for the Rutland Runway Safety Improvement Area project.
The Stone Strong blocks have had a return engagement at Rutland for yet another FAA compliance project.
“There is another taxiway at Rutland we are doing, as the original was a meandering configuration and the FAA likes parallel taxiways,” he says. “To create this new parallel taxiway, we had to pick up the grade 27 feet and make another wall, which is 690 feet long and 27 feet tall, and which has a nice curve to it.”
This is a multiyear project that’s being completed in sections. “We did the southern end a few years ago, then the northern end, and now we’re going to fill in the middle,” he notes.