Entering Loading Frame Deflections

Loading frame deform when subjected to increasing stresses. ASTM D2435 requires that a table of loading frame deflections be generated for the various loading pressures utilized in a consolidation test; readings are taken using a non-deformable disk in place of the sample (optionally with filter paper if it will be used in the actual test). When the actual consolidation test is performed test readings are adjusted to account for the measured deflections.

CONS maintains a database of deflection tables; when you start entering a new consolidation test you can select a table from this database and have the program adjust your test's readings according to the list of deflections from this table. To add your own deflection table to the database, select Options > CONS Setup then click on Deflection Tables in the left-hand navigation panel.

  1. Click on the New button in the Table box on the right side of the dialog.
  2. At the Table name prompt, enter a unique ID for your deflection table (i.e., one that's not already used for one of the deflection tables currently stored in the program's database).
  3. After you've entered your table name, pressing Enter brings you to the deflection readings grid. For each deflection reading that you've taken, enter the pressure and corresponding deflection dial reading.
    • CONS assumes that the dial gauge is zeroed prior to the start of the calibration procedure.
    • Use the same measurement units for your deflections as will be used for entering the consolidation test data.
    • All deflection readings should be positive. If your dial gauge decreases in readings with compression, you still need to enter the reading as a positive amount of deflection.
    • Deflection table pressures should be in the same units that will be used to enter your test pressures.
    • If an unload and/or reload cycle was included as a part of the calibration the table will feature multiple entries for the same loading pressure (one for the initial loading, one for the unload, then another for the reload, etc.). When CONS applies the table to your consolidation test it determines which calibration entry will be used for a given loading increment based upon whether or not the increment was an initial loading cycle, an unloading cycle, or a subsequent reloading cycle.
    • The loading increment immediately prior to a water-added cycle and the water-added cycle itself share the same loading pressure and deflection. Enter a pressure/deflection line for the loading increment immediately prior to the water-added cycle, but do not enter a line for the actual water-added cycle.