Deflection Measurements (With FWD and HWD), Analysis and Reporting

Non-destructive measurements are made with the Falling Weight Deflectometer to determine the structural strength of Highway Pavements and Airport Pavements. Structural evaluations of the coatings are made using the data obtained from these measurements and the results are reported.
All measurements and analyses are carried out by KOMSA’s engineers with measurement and analysis experience in over 12,000 km of sections with Deflectometer throughout Turkey, in accordance with the General Directorate of Highways, ASTM, AASHTO specifications.
Dynatest HWD (Heavy Weight Falling Weight Deflectometer) non-destructive measuring device is used for Deflection Measurements and Analysis.
These measurements are analysed in accordance with World Standards and Highways legislation using professional analysis software used worldwide prepared by KOMSA. All analysed data are examined and evaluated by KOMSA analysis engineers and reports are prepared in accordance with the Highways Specifications. Analysis programs to be used in the General Directorate of Highways are also developed by KOMSA specifically for KGM.
FWD transfers the dynamic loading to the superstructure, simulates the moving wheel load, and measures the deflection of the superstructure. With HWD, the load, which can be adjusted between 30 – 320 kN, is placed on the pavement and deflections at a certain distance are measured with the help of geophones on a beam. Signals collected from the loading impact area with the help of geophones and transmitted to the system processors, which ensure that the highest deflections are selected and stored in the computer memory. These data can be checked and recorded at the time of measurement. Thanks to the computer containing the monitor and test control systems mounted inside the vehicle.

KOMSA HWD Geophones

KOMSA HWD Device, which can be used on concrete and asphalt pavements, measures in accordance with ASTM D 4694 standard. It is also used in HWD pavement management systems, pavement maintenance, repair and overlay designs.
Loading is applied at a certain frequency and time interval. The impact effect applied by HWD is extremely close to the effect created by standard axle loads, even if the load application times are very different, and gives more successful results than other non-destructive testing methods (NDT).
The resulting surface deflections are measured with the help of sensors placed at increasing radial distances from the centre of the load and the surface deflection profile (deflection bowl) is determined. All characteristics of the surface deflection profile reflect the actual condition of the pavement.
After back calculation from the obtained deflection curves, stresses are calculated separately for each layer. Layer Modules are created using the data obtained.
The existing pavement structural number is calculated according to the layer modules. The required overlay thickness is found from the difference between the required pavement structural number calculated by taking into consideration the projection year, the current traffic amount and the possible traffic increase amount, and the existing pavement structural number calculated.
Back calculation and overlay thickness calculation stages are carried out by KOMSA‘s expert engineers using the AASHTO Method. All analyzes and evaluations are carried out in accordance with international specifications and the General Directorate of Highways legislation.

KOMSA Stress and Layer Module Analysis