Konferens: Ninth International Conference on Bearing Capacity of Roads, Railways and Airfields, 2013, Trondheim

The ACN/PCN method rests on the concept of a single-wheel load which has been employed as a means to define the landing gear assembly-pavement interaction without specifying pavement thickness as an ACN parameter. For flexible pavements, airplane landing gear flotation requirements are determined by the California Bearing Ratio (CBR) method for each standard subgrade support category. The CBR method uses a Boussinesq solution for stresses-strains and displacements in a homogeneous, isotropic elastic half-space. To standardize the ACN calculation, the ACN-PCN method specifies that ACN values be determined at a frequency of 10,000 coverages. This is done by equating a fictitious pavement thickness, given by a mathematical model for an aircraft gear assembly, to the pavement thickness for a single wheel at a standard tire pressure of 1.25 MPa (181 psi). Since it is generally well known and accepted that CBR method is outdated and no longer in use for pavement design and analysis purpose, this paper proposes a new approach for equating a pavement thickness which would be required by a given aircraft to the pavement thickness required for a standard single wheel-load, by using the Multi Layers Linear Elastic Analysis (ML2EA) procedure. For this first attempt, the paper does not intend to give full details on the procedure but offers the basis of a new approach with its numerical implementation and further work to be done for method refinement.