Existing airport pavement evaluation and design methodologies are primarily oriented toward larger air carrier size aircraft, and do not adequately address the requirement at General Aviation (GA) airports. Although GA pavements generally serve light aircraft, most airports need to accommodate heavier corporate or military aircraft on an occasional or periodic basis. Existing GA design method cannot handle mixed traffic, or overload operations.
To address these shortcomings and to augment its formal strength rating program, North Carolina Department of Aviation (NCDOA) conducted a two year study during 1997 and 1999 to develop standardized procedures for nondestructive testing (NDT) and evaluation of GA airport pavements and analytical software on layered elastic design theory for evaluating pavement strength and overload operations.
This study focused on flexible pavements and consisted of the following four primary elements:
- Data Analysis and Back-calculated NDT subgrade moduli were correlated with CBR and laboratory resilient modulus data for development of failure algorithms and to allow direct input of back-calculated FWD subgrade modulus into the evaluation procedure.
- Subgrade Strain Criteria and the results of a literature search and design of FAA compliant pavements over a broad range of subgrade and traffic inputs formed the basis of a new subgrade strain failure criterion.
- Development of Analytical Software and Layered elastic evaluation and design software developed using the FAA/LEDFAA software for air carrier pavement as a model.
- The new software, termed LEDGA, incorporates the new subgrade strain criterion and permits multiple airport analysis and evaluation of "overloads" based on cumulative damage concepts.
