The FWD is a trailer mounted system that imparts a dynamic impulse to a pavement through an applied load or “falling weight” and then measures the resulting seismic response using geophones to measure the change in the pavement’s velocity or “deflection.”
The data generated from a FWD is one of the cornerstones of pavement design around the world. It is used extensively to evaluate the performance, durability and expected life of pavements.
It is mandatory on all NZTA and Auckland Transport reseal and rehabilitation sites.
The pavement response is analysed with Dynatest’s Evaluation of Layer Moduli and Overlay Design (ELMOD) to determine the elastic moduli and stresses of each modelled layer. ELMOD reports the weakest layer of failure, residual life and then provides optimum rehabilitation alternatives saving time and resource for our clients.
Our FWD testing conforms to Austroads ASTM AG:AM/T006.
Benefits of the Falling Weight Deflectometer:
• Automated and rapid structural pavement testing applicable to pavements all over the world.
• Determines individual layer modulus.
• Determines the layer of failure, rather than simply determining the bearing capacity.
• QA/QC of newly built pavements.
• Compares a range of rehabilitation options, including plane off and recycling rather than just applying
• The use of the FWD provides accurate, reproducible and repeatable structural data.
• Automated and real-time monitoring of the load cell, geophones, and data variations ensures high
quality of collected data.
• Uses mechanistic-empirical analysis applicable to most of pavement structure.