Airport pavements have seen a fast increase in frequency and weight of aircraft due to a
growth in number of passengers. To cope with such a growth aircraft manufacturer design new
aircraft types capable of transporting more passengers. This results in an increase in gross weight
of the new aircraft types. An increase in the number of tires and landing gears is used to restrict
the maximum load per wheel, which resulted in the dual-tridem gear lay-out of the B777 and the
use of tridem gears for the Airbus A380. The international accepted design methods of ICAO [1]
and FAA [2,3] have not been able to keep pace with this tendency in aircraft design. A discussion
regarding this problem was started based on the ACN (Aircraft Classification Number) to be
assigned to the B777. The core of this discussion is attributed to the lack of knowledge of the
interaction between six wheels in one single landing gear. The construction of the National
Airport Pavement Test Facility (NAPTF) in Atlantic City is based on the need for developing
new design procedures for the new B777 and A380 type of aircraft.
In the mean time however the construction of new airport pavements such as new
runways has to continue, although the predicted fleet-mix does include the new generation large
aircraft. Environmental issues regarding noise reduction give cause for the need of extra runways.
The uncertainty regarding the stresses developed in the pavement structure and the uncertainty in
structural pavement life has been the motive to look for alternative pavement structures less
sensitive to the combined stresses of multi-wheel landing gears. Alternative pavements in this
case are those structures needing only relatively inexpensive corrective measures to increase the
structural capacity in case of an underestimated traffic prediction or increase in frequency or
weight of the NLA generation of aircraft types.