![]() LEDFAA’s structural model makes use of layered elastic analysis (LEA) for all types of pavement structures. Therefore, a new set of full-scale tests, involving 4- and 6-wheel gears and pavements constructed to current FAA standards, was needed. However, the failure models embedded in LEDFAA 1.2 were significantly out of date, being based on full-scale traffic tests conducted by the USACOE that ended in the early 1970’s. LEDFAA is a mechanistic-empirical design procedure in which computed responses are related to pavement life predictions through empirical failure models. The major problems with LEDFAA 1.2 fell into two areas: LEDNEW was adapted to meet FAA requirements and released as LEDFAA version 1.2 in 1995.Įven though LEDFAA 1.2 provided a short-term solution for pavement designs involving 6-wheel gears, it was recognised that a significant R&D effort was needed to develop a computer-based method that would be able to handle complex gear configurations for new large aircraft, and would fully replace the design nomographs for the existing fleet. LEDNEW, a computer-based design procedure involving layered elastic computation of stresses and strains, was originally developed by the US Army Corps of Engineers (USACOE). Fortunately, an alternative procedure was available. ![]() At the time, it was recognised that design nomographs for the unique 6-wheel gear did not exist, and moreover, that the extension of the underlying design method (in particular the CBR equation with alpha factor) to 6-wheel configurations and higher might not be correct. The FAA’s transition to computer-based design procedures has been gradual, and was originally driven by the introduction of 6-wheel aircraft gears in the 1990’s, as represented by the Boeing B777. The revised AC will make FAArfield the FAA’s standard thickness design procedure for both rigid and flexible pavements, including overlays, and will retire the FAA nomograph-based design procedures. In addition to putting the finishing touches on the FAArfield software, the FAA is also substantially rewriting the Advisory Circular (AC) covering Airport Pavement Design and Evaluation (AC 150/5320-6D). The new program is called FAA Rigid and Flexible Iterative Elastic Layered Design, but is known by its acronym, FAArfield. ![]() * Pavement Calculator download link provides trial version of the software.After a 10-year research and development effort, the Federal Aviation Administration (FAA) is set to debut a new software package for airport pavement thickness design. UFC flexible pavement - flexible pavement thickness, stabilized soil flexible pavement thickness, pavement frost penetration depth and pavement frost penetration base thickness.UFC rigid pavement - roadway rigid pavement thickness, parking lot rigid pavement thickness, rigid pavement thickness on stabilized soil, reinforced rigid pavement thickness, rigid pavement joint length.AASHTO flexible pavement - flexible pavement structural number, trial section flexible pavement ESAL loading.AASHTO rigid pavement - trial section rigid pavement ESAL loading, rigid pavement steel area.Performs civil engineering calculations for traffic/road geometry, surveying/earthwork, pavement, concrete floors and unit conversions. ![]() Stand alone software version of the pavement design portion of the CE CALC website. ![]()
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