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Normalise FWD Deflections in JunoViewer Messages in this topic - RSS

Fritz Jooste
Fritz Jooste
Administrator
Posts: 81


10/1/2019
Fritz Jooste
Fritz Jooste
Administrator
Posts: 81
Falling Weight Deflectometer (FWD) deflections are measured at a specific plate pressure. The plate pressure will vary from one reading to the next because of surface irregularities and the pavement response. To compare deflections from one point to the next, you can run the "Normalise Deflections" function which can be found under the Tools Menu on the Data Manipulation page.

The formula for calculating the Normalized deflection is: D_norm = (Pressure_Normalize / Pressure_Actual) * D_raw

Where:
  • Pressure_Normalise is the selected normalisation pressure (see image below);
  • Pressure_Actual is the actual measured pressure (presumed to be stored in column "pressure")
  • D_norm is the normalised deflection or deflection bowl parameter
  • D_raw is the raw deflection or deflection bowl parameter

Note that Normalisation does not alter the data in your raw deflection columns. It merely normalises the maximum deflection in column "YMax", and if selected, it also normalises the deflection bowl parameters SCI, BLI, MLI and LLI.


By default, the FWD normalisation function will assume that your database contains a table named "fwd", with the following columns:

  • "pressure" (holds the actual measurement pressure)
  • "YMax" (holds the normalised maximum deflection)
  • "D0" (holds deflection at zero mm offset)
  • "D200" (holds the deflection at 200mm offset)
  • "D300" (holds the deflection at 300mm offset)
  • "D600" (holds the deflection at 600mm offset)
  • "D900" (holds the deflection at 900mm offset)

If you tick the box "Add normalisation parameters" (see image above), then your FWD table also needs to have the following columns:

  • "SCI" (holds the Surface curvature index)
  • "BLI" (holds the Base Layer Index = D0 - D300)
  • "MLI" (holds the Middle Layer Index = D300 - D600)
  • "LLI" (holds the Lower Layer Index = D600 - D900)

If your FWD table contains similar columns but uses other names, then a custom normalisation setup can be created for your account. Contact Lonrix for details on how to set this up (no charge involved).


Currently JunoViewer allows two formulae for calculating the Surface Curvature Index. Use the dropdown box (image above) to select the equation you want to use.


edited by Kiki on 8/18/2022
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