Falling Weight Deflectometer (FWD)
The Falling Weight Deflectometer (FWD) is an essential tool for evaluating the structural condition of pavements. It provides a non-destructive and efficient method for assessing the structural capacity of pavements, whether it's for research, design, road rehabilitation, or pavement management purposes.
Pavement engineers rely on the Falling Weight Deflectometer (FWD) to assess pavement conditions, performance, and determine the need for rehabilitation or reconstruction. The data obtained from the FWD also helps optimise pavement design and maintenance strategies.
With the Dynatest Falling Weight Deflectometer (FWD), a dynamic load is applied to simulate the loading of a moving wheel. Dynatest's ELMOD (Evaluation of Layer Moduli and Overlay Design) software is used to analyse the pavement response, providing information on elastic moduli, stresses, and strains for each layer. ELMOD identifies the weakest layer, residual life, and suggests the best rehabilitation options. The FWD is available in both trailer and truck-mounted versions, meeting FWD standards worldwide (trailer version available globally, truck-mounted version available in the USA).
Key Benefits and Features:
- Automated and quick testing applicable to pavements worldwide
- Identifies the layer of failure, going beyond bearing capacity determination
- Quality assurance and quality control for newly constructed pavements
- Evaluates various rehabilitation options, including plane off and recycling, not limited to overlays
- Provides accurate, reproducible, and repeatable structural data
- Real-time monitoring of load cell, geophones, and data variations ensures high data quality
- Applies mechanistic-empirical analysis suitable for most pavement structures
- Used globally in diverse climates, from hot deserts to humid tropics and polar regions
- Compliant with ASTM D4694-09 and ASTM D4695-03, along with equivalent standards
- Successfully passed TRL (UK) and CROW (Netherlands) correlation trials
- Calibration protocol compliant with AASHTO R32-11
Key Operational Features of the Dynatest FWD
- A non-destructive test device.
- One man operational.
- Total flexibility with 7-15 deflection sensors.
- Accurate and fast (up to 60 test points/hr with a typical 4 load application sequence).
- No need for road closure.
- Wide loading range: (7-120 kN) or (1,500 – 27,000 lbf). Extendable to up to 150 kN (33,700 Ibf)
- Designed for multi-purpose pavement applications, ranging from unpaved roads to airfields.
- Excellent repeatability.
- Ideal for mechanistic/analytical design approaches.
- 4 segmented loading plates to test uneven or rutted pavement surfaces
- Air and Pavement Surface Temperature Sensors.
- Distance Measuring Instrument (DMI).
- High quality for long lasting functionality.
- The most tested FWD on the market.
Available Upgrade Options
- Folding trailer for ease of shipment
- Global Positioning System (GPS)
- Additional deflection sensors (up to 15)
- Camera system for plate location or photo-logging
- On board generator for standalone operation
- Trailer cover (soft or hard versions)
- Trailer mounted light(s) or strobe(s)
- Rear and side Sensor Extension Bars
- Ground Penetrating Radar
- Rear warning sign
- Spare parts kit
- Tool kit
The use of Falling Weight testing
Data collected from the Dynatest FWD can be used for determination of the structural capacity of in-service pavements to analyse the physical properties of the pavement. When analysing the data from the Dynatest FWD with the ELMOD software, it is possible to obtain information about the condition of the road, such as: surface layers, subgrade layer, layer moduli, layer types, thickness, range of moduli, Poisson’s ratio and bearing capacity.
This information can be used to estimate overlay requirements, the remaining life of the pavement, and an effective creation of a Pavement Management Plan.
ELMOD Software - only available for Dynatest Equipment
- Evaluation of Layer Moduli and Overlay Design
- Dynatest’s ELMOD software may be used for the analysis and design of flexible, rigid, and composite pavements
- Allows quick data reduction and analysis of FWD load/deflection measurements
- Capable of backcalculation of the layer moduli, for a typical drop sequence, in less than a second
- Fast calculation of the seasonally adjusted moduli, residual life of the pavement, and required overlay thickness for a given service life
- For maintenance and rehabilitation (M&R), the LCCA (Life Cycle Cost Analysis) module allows the user to select the optimum M&R solution
for a pavement section according to cost/benefit ratios
- For analysis of airfield pavements, the optional PCN module calculates PCN in accordance with the ACN/PCN method, as described in the ICAO and FAA design manuals