1666359 - Remaining Pavement Life Computation Using Cumulative Damage Factor

Abstract: The U.S. Department of Defense (DoD) airfield pavement structures have been designed for decades based on the calculated stresses by military aircraft operations. The existing standard design methods have been used successfully and provided warfighters sustainable and durable facilities to increase their readiness. The Pavement Computer Assisted Structural Engineering (PCASE) program which accepts the California Bearing Ratio (CBR) procedure and the layered elastic model to design and evaluate the U.S. Department of Defense (DoD) pavements was used for the computations in this paper.

The CBR equation for flexible pavement design in the program and the Aircraft Classification Number (ACN) equation expressing the relative effect on an aircraft of a given weight on a pavement structure, for a specified standard subgrade strength – in terms of a standard single-wheel load, were used for a numerical solution to compute Cumulative Damage Factor (CDF). An aircraft overload concept was added to the CDF computations to simulate excessive stresses from aircrafts in expeditionary environments. Military aircraft operations under the expeditionary environments were implemented by the CBR design method to characterize pavement damages which has been adopted for civilian airport pavement design as well. Maritime patrol and reconnaissance aircraft P-8A Poseidon, its predecessor P-3 Orion, and Boeing 737-800 were selected for the characterizations. Since P-8A is derived from Boeing 737-800, the civilian aircraft was included in the characterizations for comparison purpose.

Computed CDF quantifies pavement damages under excessive aircraft operations that enables military air base/civilian airport authorities to estimate pavement life reduction (or remaining pavement life) from the original structure design. Procedures were proposed for how to quantify the potential pavement damages and respond in expeditionary environments such as combat loading conditions or aircraft overloading including emerging new aircrafts with excessive stresses that were not considered in original pavement structure design.

Results from the characterizations also showed potential premature pavement failures under aircraft operations in expeditionary environments and supported the need to develop a separated runway pavement design for expeditionary environments from the existing standard pavement design.