When the U.S.
military needs to utilize runways in foreign countries, the load carrying capability is often unknown.The best method to determine the suitability of a road or runway is to measure the stiffness under load.Historically this has been performed with a falling weight deflectometer www.dynatest.com.Although this method is quite
accurate, it is very slow.The Air Force needed a method that could rapidly assess
the stiffness of the runway under load.
Solution:
QUEST developed a rolling weight deflectometer mounted on a trailer that can be towed up to 20 mph.Sensors are mounted on a beam suspended under the trailer that measure the distance
from the beam to the runway surface.During operation, the optical sensors measure
the distance from the beam to the surface without a load and then as the trailer moves forward, the sensors measure the distance
from the beam to the surface under load.The difference between the loaded and
unloaded surface deflection is a measure of the runway stiffness and quality.An
enabling feature of the device is a laser-based straightness measurement system that provides an infinitely stiff reference
beam.
