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Runway Paving Boom Looms as Many Near Lifespan End

Mon July 10, 2006 - National Edition
Giles Lambertson



Runway construction work in the United States is not poised to take off, but neither is it in a holding pattern.

Airport officials said the nation’s paved landing strips generally are in good repair. Yet some new dynamics in aviation are changing assumptions and could lead to redevelopment of airport property and facilities.

A variety of factors will drive any new round of work on runways, gates and terminals, industry observers said. Something as mundane as new respect for preventative maintenance might trigger additional contract work. A new type of jet plane also holds promise.

Furthermore, federal regulation and policy changes are having an effect.

As a construction market, airport numbers are impressive. The Federal Aviation Administration reports that the United States is home to 19,815 airports, most of which are for public use. They’re being used by approximately 750,000 pilots licensed to operate aircraft above America’s soil.

The FAA categorizes all of these airports according to size and function. The gamut runs from large hub airports, through which 70 percent of commercial air travelers pass, down through a descending order of airport types labeled as medium hubs, small hubs, non-hub primary, commercial, reliever (small airports near enough a hub to relieve flight congestion), general aviation and approximately 2,000 others too small to be classified.

All these airports across America are the infrastructure on the ground for the aeronautical highways that crisscross the sky. They are the places where approximately 50,000 airplanes a day descend, touch down their landing gear and taxi to a parking area, or rev up their engines at one end of a runway before racing down it and lifting off.

The condition of these busy runways obviously is vital to the safety of the many thousands of people flying each day as well as to the viability of airports that serve them. The current “National Plan of Integrated Airport System” report concludes that 75 percent of runways in the country are in good condition and 21 percent are in fair condition. Looking at just commercial airports, the percentages were 80 percent good and 18 percent fair.

As a comparison, the report noted that a few short years ago the condition of America’s highways was judged to be 49 percent good and 42 percent fair.

Runway standards obviously are high. Arthur G. Allen, chairman of the Massachusetts Aeronautics Commission, was asked if the condition of any of the 38 public use airports in his state are in a state of significant disrepair.

“None are crisis situations,” he said. “We could not run an airport with a runway in a crisis condition. A runway with a pothole or a deteriorating edge could be life-threatening.”

In other words, runways generally are not hazardous even in their worst functioning condition. They are closed before they reach a dangerous state. In Massachusetts, for example, a third of the airports are in good shape, Allen said, and a third need some form of improvement such as resealing of joints. The remaining third “should be in the works for replacement.”

The useful lifespan of a runway typically is 15 to 20 years. Using that standard, Dan Malloy suspects that many runways around the country are on their last legs.

Malloy is assistant general manager of Atlanta’s Hartsfield-Jackson International Airport, which is the busiest airport in the world. Malloy knows runways, having helped oversee construction of the airport’s $1.3 billion fifth runway, which was completed in May. A second of four other runways is being rebuilt this year and yet another one sometime in the next five years.

Malloy also is chairman of the Technical Affairs Committee of Airports Council International-North America. His perspective, in other words, goes well beyond the Georgia border and Malloy believes America’s runways are wearing out.

“I think there is more infrastructure coming to the end of its useful life than is at the beginning of it. That’s my gut instinct,” he said.

Even so, he cannot put a firm timetable on the deterioration because the 15- to 20-year standard is hardly a fixed one: Hartsfield-Jackson has gotten 30 years out of one runway, he noted, and 27 years out of another one.

Material Choices Vary

The 15- to 20-year standard is a benchmark. When runways are built, they are expected to bear up at least that many years under the weight and pressures exerted by landing and departing aircraft.

As a rule, paved runways at larger hub airports are concrete, while most general aviation and smaller airport runways are asphalt. The more rigid concrete is preferred for airports serving huge commercial jets, those ranging up to the next generation Boeing 787s and Airbus A380s, aircraft whose weight and drop force exert tremendous downward pressure upon runway surfaces and subsurfaces.

To resist such forces, the brand new runway at Lambert-St. Louis International Airport, for example, consists of 10 in. (25 cm) of crushed rock, 6 in. (15 cm) of permeable concrete and a surface cap of concrete fully 18 in. (46 cm) thick.

Runways are calibrated for specific loads. Such calibration is the whole reason for a “National Airport Pavement Test Facility” built nine years ago in Atlantic City, NJ, by the FAA and Boeing Aircraft Company. The building is 1,200 ft. (364 m) long and contains a 600-ton (540 t) test vehicle that can apply individual landing gear pressure of up to 75,000 lbs. (33,750 kg) per wheel. Sets of landing gear are run back and forth across pavement test sections 24 hours a day until the pavement buckles or wears out.

So contractors have a pretty good idea of the best and worst characteristics of pavement. The choice of material varies from state to state and airport to airport — and types of airplanes landing on a runway are just one factor. Sometimes cost is the final determinant; in other cases, the specific area of an airport to be paved determines the paving material. For example, regardless of a runway’s construction material, apron areas where planes are parked and fueled are more likely to be concrete because concrete is impervious to fuel spills.

“Nationwide, 90 percent of runways are asphalt, 10 percent concrete,” the FAA’s Rodney Joel said. He is in the Kansas City FAA office of Airport Safety and Standards, dealing specifically with pavement design and maintenance. “But in terms of square footage, it is probably 80 percent asphalt,” an acknowledgement that concrete runways are fewer but generally larger.

In Massachusetts, “tar is the magic surface,” according to Allen, the state’s aeronautics commission chairman. “All public use airport runways in Massachusetts are tar and probably will stay tar.”

Preventative Maintenance

The situation is not much different in a state a little farther north but a whole lot farther west: Montana.

While one or two airports in Big Sky Country might have runways formed of concrete, the other 56 airports are paved with asphalt, said Bill Burkland, an engineer at Robert Peccia and Associates. The engineering firm has a long-term contract with the FAA and the Montana Aeronautics division of the state Department of Transportation to inspect and analyze the state’s non-primary runways. Burkland leads the effort as assistant manager of the airport division of the company.

He noted the U.S. Army Corps of Engineers has been testing the quality of pavement since the 1940s — “60 good, solid years of research” — and has concluded that preventive maintenance of pavement before it goes bad “gives the most bang for the buck.”

The FAA has bought into the preventive concept, he said, and airport owners now are investing in runway maintenance “before it looks bad, before it starts falling apart… preventive maintenance is extremely cost-effective.”

Burkland talked about the value of patching cracks and of “fog sealing,” which is a computer-controlled application of emulsified asphalt using a distributor truck. The liquid seal can renew the surface once every four or five years, for a contracted annual price of approximately $50,000. That compares to the several hundred thousand dollars it costs to fully reconstruct a runway.

“We used to look at 20 years of life for a runway, but that’s just not true anymore,” he said. “You have to significantly overload a runway to have a pavement life that short.”

He said preventive maintenance on asphalt runways “has extended the plateau on pavement life. At this time, it appears to be about five years longer.”

Maintenance includes sealing cracks so that moisture cannot penetrate the pavement and undermine the base, allowing it to “move” when an airplane runs across it. The emulsifier treatment fights the deteriorating effect of sunlight on asphalt.

“The asphalt’s job is to hold together the aggregate,” Burkland explained. “Sun breaks down its ability to hold the rock together. The emulsified asphalt rebinds the surface, which is the exact area that the sun is making more brittle.”

Asphalt material applied to a runway is somewhat different than sealer applied to parking lots. Parking lot applications usually are chip seal jobs intended to extend the wearing surface of pavement. The runway sealer is not an antidote for physical wear; rather, it protects against ultraviolet degradation of the surface.

In any case, runways eventually do wear out, Burkland acknowledged. “We are still in a cycle of needing periodically to reconstruct runways, but preventive maintenance has extended the cycle of reconstruction.”

Burkland credits the FAA with dispersing available money thoughtfully in Montana, so that the larger runway reconstruction jobs don’t all come up at the same time. Consequently, he doesn’t believe the state is behind the curve on runway repair.

“I don’t see a huge deficit,” he said. “I don’t see that happening here.”

Switching to Concrete

On the West Coast, Kim Ellis last year watched over the transformation of a 10,000-ft. (3,033-m) runway at Ontario International Airport in southern California. The runway — one of two on the property — was converted to concrete from asphalt to accommodate larger, heavier airliners the airport hopes to attract in greater numbers. The contractor on the runway job was Griffith Company.

Ellis was acting airport manager during most of the year the runway was being rebuilt, a project that came in on schedule, on budget and was completed “smoothly,” Ellis said. In May, Ellis became the permanent assistant airport manager, which allows him to continue to teach airport planning and management at the Riverside campus of Embry-Riddle Aeronautical University.

He said the switch to concrete pavement was in anticipation of a sharp increase in traffic of the larger jets. It also was practical recognition that the range of temperatures in San Bernardino County, sometimes topping out at 110 degrees, can break down asphalt more easily.

“Concrete is really easy to work with, especially in this environment,” Ellis said. “Asphalt is real good, too, but if there are any flaws in the mix, it won’t last the 15 to 20 years expected of it.”

The assistant manager acknowledged that he has heard comments about a looming shortage of runways, but he doesn’t see much evidence of it in southern California. What he does see is a shortfall of terminal space.

“We’re using a little over 50 percent of our runway capacity. We’re going to run out of gates before we hit our capacity to land planes,” he said, adding that the possibility of a gate shortage has only begun to be talked about.

The Los Angeles World Airports system that operates Ontario has a sister airport at Van Nuys in the San Fernando Valley. It is the world’s busiest general aviation airport, its two runways serving approximately 420,000 private, charter and small commercial aircraft flights last year. Van Nuys’ 8,000-ft. (2,426-m) and 4,000-ft. (1,213-m) runways are asphalt, with concrete reserved for ramps and aprons.

Airport manager Selena Birk said her runways probably are in the middle of their useful lives. The shorter runway was renovated approximately 10 years ago, with all traffic diverted to the longer one. That switch won’t work when the longer runway needs major repair in approximately 10 years.

“That will really be challenging,” Birk said.

She noted that working the runway ends won’t be too tricky while air traffic continues to land and take off, but when the middle of the strip needs tearing up, “That will be interesting.”

Her administration already is working long-term with a firm about the capital and logistical requirements for reconstructing the longer runway.

New Runways a Quick Solution

Across the country, federal policies also are having some bearing on runway contract work. The Bush administration in 2001 acted to reduce environmental pre-conditions for runway construction. Heretofore, it has taken 10 years on average to complete an airport environmental review process, which in the 1990s translated into just six new airports being built.

The FAA simultaneously decided to promote new runways as the first answer to reducing congestion at major airports across the country. Runway construction thus was given priority above more technological innovation and more air controllers.

“Overall, runways produce the greatest amount of capacity compared to all other actions out there,” declared Steven Brown, the FAA’s chief of air traffic services.

And a new type of aircraft is viewed by some as a potential catalyst for changing the pattern of air travel in the country and creating additional need for longer and better runways at smaller airports.

The aircraft is called a “very light jet.” It costs approximately a fourth of what a small corporate jet will cost a buyer — some are selling for a little more than a million dollars — and can land on runways as short as 2,300 ft. (300 m). The latter capability is expected to open up the small jet to use in as many as 10,000 airports.

Small jets, large jets, aging runways, underbuilt terminals, renewed emphasis on preventive maintenance, eased environmental regulations — all of these factors add up to the possibility of a surge in airport work in the next decade. CEG