Runway rollout

Warwick Beacon ·

Maybe it’s only appropriate that a project that has been studied, debated and the cause of litigation for decades have a Dec. 7 – Pearl Harbor Day – deadline for completion. That’s Dec. 7, 2017, the day a 1,524 extension to Runway 5 at Green Airport will open.

“It’s going to be a day that lives in infamy if we don’t finish,” says Paul McDonough, who is coordinating the $38 million project.

The extension will give Green an 8,700-foot runway with the capability for airlines to provide nonstop service to the West Coast as well as operate at full capacity on shorter runs in the heat of summer when greater runway space is needed for takeoffs.

Ever since the City Council dropped a suit to halt the extension and signed a memorandum of understanding five years ago that spelled out obligations for both parties, the extension has been the crowning piece of a series of projects, including the extension of the safety zones on the shorter runway, relocation of Winslow Park playing fields, and the relocation of Main Avenue. Simultaneously, as part of that agreement, the Rhode Island Airport Corporation has brought and sound-insulated homes in the path of the longer runway and its safety zone.

Work on the runway extension started this summer and has not missed a beat since, McDonough said during a tour of the project Thursday with Gregory Fehrman, principal engineer with C&S Companies. Not a single day has been lost to weather conditions and the project is slightly ahead of schedule and on budget.

The work this year, scheduled to come to a halt Nov. 9 and recommence on April 1, 2017, is largely taking place 600 feet from the end of the runway. Building from the end of the extension toward the existing runway, McDonough explained, allows for uninterrupted airport service while putting in place the lighting and land instrumentation for the longer runway so that when the two ends are joined everything is in place and ready.

As can be seen from the relocated Main Avenue, the blast deflector – built entirely of fiberglass so as not to interfere with any aircraft navigational instruments – is in place. Behind it is the bed for the engineered material arresting system, or EMAS, designed to stop aircraft that overshoot the end of the runway. Installing the EMAS – which consists of concrete blocks designed to crumble under the weight of an aircraft – will take place next year.

Meanwhile, Cardi Construction Co., low bidder for the project, has already completed a portion of the taxiway to the end of the runway as well as the extension.

The work may look no different than building a road, but that’s hardly the case.

Runway elevations and dimensions must be precise to work in concert with navigational systems. This means excavating to specific levels so as to provide for the exact amount of base material – like baking a layered cake – to arrive at exactly the right runway height at that specific location. The runway is not a flat surface, but rounded to provide for drainage and has a varying elevation.

For the first time in New England, Fehrman said, a “robotic” system is being employed to arrive at the required measurements as designed by engineers with the assistance of computer programs.

“A robot is deciding and automatically grading to level,” Fehrman said.

The system, as explained by Matt Sullivan and Wayne Hopkins, who were on site, is guided by a GPS system that at any one point in time may be reading as many as 30 satellites. That information is displayed on a handheld tablet and fed into controllers on dozers and grading equipment. The operator drives the unit while the controllers set the blade to achieve the assigned elevation to within three-eighths of an inch.

Likewise, the composition of the runway must meet specific requirements.

The first job was the removal of topsoil, which, not surprisingly, is rich as the area was a farm before Warwick’s rapid suburban development following World War II. That has been stockpiled and will be used in the finishing phases of the project.

McDonough said that virtually everything is being recycled, from the chain link fencing and concrete structures to the chewed up pavement of the former section of Main Avenue. Concrete and millings from Main Avenue have been ground up and are mixed with gravel as the initial six-inch sub-base to the runway. A six-inch layer of gravel follows that. Topping off the gravel is 10 inches of bituminous concrete that gets a four-inch frosting of surface coating.

Runways require 100 percent compaction of materials as compared to 95 percent for roads, said McDonough. “It’s beefy.”

McDonough, who directed construction of the newest runway at Boston Logan Airport, said runway specifications are based on the mix of aircraft projected to use it. It is designed for a 20-year lifetime. An FAA inspector is on site throughout the construction process.

Off-runway conditions, down to the grass, are likewise regulated. Water runoff is captured in swales where it filters into the ground. These temporary retention basins cannot have standing water for more than eight hours.

The concern is birds, especially Canada geese and other waterfowl congregating near the runway. In addition, the grass being planted near the runway has been developed to discourage birds from feeding.

McDonough said a variety of strategies has been used to inhibit the congregation of birds from the use of netting and dogs to the spraying of grape juice, which apparently geese haven’t developed a taste for. Even the periodic firing of canons has lost effectiveness as birds have become accustomed to the noise.

“It’s a constant battle,” McDonough said.

And then there is the grass. The endophyte strain of grass, which contains a fungus, has been shown to discourage birds from feeding. The grass is green and growing rapidly to Fehrman’s satisfaction.

But for all that has gone into coordinating the project this year, the real dance starts next year.

“This is the warmup,” said McDonough. “The real show starts April 1.”

It’s at this point that crews move within 600 feet of an active runway.

So as not to interrupt airport operations, much of the work will occur following the last departure at about 9:30 p.m. and before the first morning flight at about 5:30. Staging of equipment will need to take into consideration wing clearances as well as the runway guide path.

“Next year we’re going to have twice the work in half the time,” Fehrman said.