The RODOS company evaluates the load-bearing capacity of airport surfaces based on the measurement of deflections with the impact device HWD (Heavy Weight Deflectometer). The device enables load tests to be carried out with a damped impact with the required load simulating the load on the airport roadways of the aircraft landing gear, up to a load of 300 kN or with a contact pressure of 4.25 MPa. A wide range of load force settings enables the measurement of deflections of airport surfaces from small sports airports to the largest international airports. The load force is chosen with regard to the type of road and the planned load from airport traffic so that the induced deflections are in the optimal range for further processing.

In the course of HWD measurement, we perform a visual inspection of airport surfaces and record the condition of the surface with a high-frequency camera. We take into account the range of faults and their severity, which have an impact on the overall evaluation of the bearing capacity and ensure the determination of the Pavement Condition Index – PCI (ASTM D5340 – 20: Standard Test Method for Airport Pavement Condition Index Surveys).

Calculations of bearing capacity by ACR/PCR method

are carried out by the Federal Aviation Administration (FAA) FAARFIELD program based on the measured deflection values ​​with the HWD impact device. These tests achieve a realistic evaluation of the state of the individual structural layers. The subsequently determined PCR value expresses the actual bearing capacity of the roadway structure. The calculations respect the requirements of ICAO – Aerodrome Design Manual, Part 3 – Pavements (Doc 9157 – Part 3 of 2022) and EASA regulation (Easy Access Rules for Aerodromes, Regulation No. 139/2014).

Example of PCR evaluation in FAARFIELD

Calculations of bearing capacity by the ACN/PCN method

are carried out by the US Army PCASE program based on the measured values of deflections with the HWD impact device. These tests achieve a realistic evaluation of the state of the individual structural layers. The subsequently determined PCN value expresses the actual bearing capacity of the roadway structure.

Example of PCN evaluation in PCASE

We determine the PCR and PCN values ​​for each airport area and take into account:

  • mutual integrity of the bearing capacity of individual areas (i.e. the possibility of aircraft movement starting from the runway, then moving along the TWY to the APN and back),
  • respects the marketing plans of the airport,
  • respects airport maintenance and reconstruction plans.

We determine the PCR and PCN values ​​for the planned airport traffic load:

  • for a short period of time (1 to 5 years) in case of poor condition of the surfaces or if the deflections measured by HWD reach such values ​​that it is necessary to plan a timely reconstruction.
  • for a long time (5 to 10 years) in the case of new surfaces and older surfaces in good condition.