Falling
Weight Deflectometer - FWDs are test systems for performing
non-destructive testing of pavements and other foundation
structures. The system develops forces from the acceleration
caused by the arrest of a falling weight and these forces are
transmitted onto the surface of a structure causing it to
deflect as much as it would due to the weight of a passing wheel
load. The deformation of the structure is referred to as a
"deflection basin" and a series of user positioned
velocity sensors automatically determine the amplitude and shape
of this deflected basin. The deflection response, when related
to the applied loading, can provide information about the
strength and condition of the various elements of the pavement
structure. Abatech's staff members have been involved with FWD
testing and analysis since its inception in the 1980s providing
solutions to countless pavement structures around the world.
Abatech operates a state-of-the-art JILS Falling Weight
Deflectometer which has been used for projects in Europe, the
Caribbean and the USA. Abatech has developed numerical
procedures for pavement design and is a leading organization in
writing software applications. The DAPS software (Deflection
Analysis of Pavements.
Light Weight Deflectometer - LWDs (or dynamic loading plate)
enable the determination of appropriate stiffness of pavement
foundations (modulus value) is critical in that it allows
pavements to be deigned using analytical methods and/or methods
such as the 1993 AASHTO method.
All these methods make use of a foundation modulus value
in determination of the pavement structure.
Many methods exist to provide an estimate of the Efoundation
of a road pavement. Methods
such as California Bearing Ratio (CBR) testing provide an
empirical correlation to a modulus value and have been in use
for many years. More
recently the Falling Weight Deflectometer (FWD) testing has
become the standard for assessing the stiffness of road
foundations. However,
the use of the FWD requires that the site to be evaluated is
relatively easy to access and can be reached with a vehicle/tow
vehicle in a reasonably cost effective manner.
This is not always possible with remote sites and
consequently other methods are needed.
This could involve the use of tests such as CBR and
empirical correlations. However,
more recently sophisticated lightweight deflectometers (LWD)
have become available that are portable to remote sites,
enabling direct computation of Efoundation values.
Dynamic Cone Penetrometer: This device can help to assess
the strength of granular pavement layers including soils and
subbase materials.
NORTH BERGAN,
NEW JERSEY
Pavement investigations: Can
involve a wide range of specimen collection followed by detailed
chain-of-custody documentation followed by various lab
testing. Testing is supplemented by other studies such as
FWD, laser surveys, ground penetrating radar, DCP, light weight
deflection testing, etc.
Abatech has access to a large range of laboratory testing procedures and uses the most sophisticated analysis and integration
of results to provide clients with a realistic and meaningful analysis
of laboratory test results.
|
TESTING PORT
PAVEMENTS WITH THE JILS FWD SYSTEM
BALTIMORE, MARYLAND
LIGHT WEIGHT
DEFLECTOMETER
TESTING A PAVEMENT FOUNDATION
OIL REFINERY, TEXAS |
