FALLING WEIGHT DEFLECTOMETER (FWD)
PRI2100 FWD trailerThe PRI 2100 FWD trailer is the classic and flexible solution . Mounted on a double-axle trailer it is independent of the towing vehicle and can be towed by any vehicle. The only cable connecting the trailer with the towing vehicle is the PC computer cable. The operator controls all FWD functions from the PC, which is placed in the towing vehicle. This makes the measuring work simple and easy and only one operator is needed for the work.
The modular principle means that there is no need for investment in new equipment if the demands on the equipment change. All that is necessary to upgrade the equipment from a standard 7-150 kN FWD to a 7-250 kN Heavy Weight Deflectometer (HWD) is to add more weights, a larger load cell and upgrade software. The trailer-mounted FWD can also be integrated in a van without having to invest in new basic measuring equipment.
The standard trailer-mounted FWD is supplied with personal computer, Windows FWD software, time history module, transport lock, DMI (Distance Meter Indicator) integrated in the software, three temperature sensors, four-split loading plate, 9 geophones and warning lights. Additional functions can easily be added such as video or marking equipment, GPS (Geographic Positioning System), which enables presentation of data in maps or general plans of site.
The RoSy DESIGN, a back-calculation software for both road and/or airport data analysis. However, files generated from the equipment can be applied in any other back-calculation program.
The importance in supplying safe and stable equipment and the newest technology forms the basis of the FWD equipment. The PRI 2100 software incorporates alarms that are displayed on the computer screen. If the operator ignores vital warnings, certain functions cannot be performed with the FWD e.g. in connection with pavement temperature measuring: After having inserted the asphalt temperature sensor in a hole in the pavement, the sensor registers when the temperature is stable. The temperature is measured while the loading plate is placed on the pavement and cannot be raised before the temperature sensor is placed in its holder. The equipment cannot be driven to another position with the loading plate down and strategically placed emergency switches allows the operator to stop the equipment at any time while operating manually.
The measured set of data (peak load, deflection values, distance from start point, air and surface temperatures) is displayed on the micro computer for direct visual inspection, and is printed out and stored on disk when accepted by the operator.
PAVEMENT ANALYSIS AND DESIGN
Information about layer thicknesses and expected traffic load during the desired period combined with the FWD generated data enable calculation of the E-moduli of the pavement.
Structural analyses to determine the bearing capacity and to estimate expected service life and required overlay are easy and fast with the Design Computer Program.