Resumen de Airport pavement design for the 21st century
In Fiscal Year 2009, we expect U.S. airports to spend several billion dollars on capital improvements, for which FAA will provide more than $2.5 billion in AIP (Airport Improvement Grant) grants. The AIP grants come with some strings: airport operators agree to meet FAA standards for design, engineering, and operations. The Office of the Associate Administrator for Airports within the FAA maintains more than 100 advisory circulars that provide standards and guidance on: airport planning and design, airport equipment and construction, airport lighting and marking, airport pavement design and construction, runway safety, airport fire and rescue, and wildlife hazard mitigation. The R&D programs conducted at the Technical Center provide necessary data for updating advisory circulars and equipment specifications. Today, I will focus my remarks on advances in airport pavement technology.
Over the past 15 years, aircraft manufacturers have introduced a new generation of airplanes that are longer, wider, and taller while increasing the number of landing gears to support the extra weight. Pavement design procedures in existence before the introduction of these new aircraft were not adequate for analyzing how these aircraft would affect the design life of existing pavements. Extrapolation of existing criteria indicated that the pavements would need to be strengthened costing approximately $1.7 billion over several years. Federal Aviation Administration undertook a10-year comprehensive R&D program to resolve this dilemma. An essential element of the plan is a comprehensive test and verification program performed on real pavements subjected to full-scale loading. The FAA’s National Airport Pavement Test Facility was built. It is capable of full-scale loading up to 75,000 pounds per wheel on two landing gears with six wheels per gear. The 60-ft wide test sections provide two traffic lanes to compare the performance of 6-wheel and 4-wheel gears simultaneously. In operation since 1999, the facility is providing exciting new information in updating pavement design technologies around the world.
With the addition of two more modules on each carriage, the overall capability of the test vehicle has been expanded to permit up to five dual-wheels in tandem on each carriage. This upgrade allows the facility to conduct full-scale pavement tests for current ten-wheel landing gear configurations (Antonov AN-124) and future commercial aircraft that might use either eight or ten wheel landing gear configurations. In addition, the new modules will also be capable of steering up to a maximum of five degrees from the longitudinal centerline of the wheel group.
After our 10-year R&D effort, the FAA is set to debut a new software package for airport pavement thickness design. The new program is known by its acronym, FAARFIELD.
A substantially rewritten Advisory Circular (AC) will make FAARFIELD the FAA’s standard thickness design procedure for both rigid and flexible pavements, including overlays, and will retire the old nomograph-based design procedures. The FAA is also providing new software products for the aviation community: COMFAA for PCN evaluation; BACKFAA for backcalculation from FWD data; ProFAA for computing pavement roughness indexes; and PAVEAIR, FAA’s forthcoming software for comprehensive airport pavement management.
Development of all these products reflects the capabilities of the state-of-the-art facility that will celebrate its tenth anniversary this year.
