Calibration of the Light Falling Weight Device (dynamic load plate)
The Light Falling Weight Device (LFWD) is used to perform the dynamic load plate test. This field test provides characteristic values for compaction control and for assessing the load-bearing capacity
- of planum or TRAGSCHICHTEN in earthworks and road construction,
- of construction backfills,
- of trenches and
- other fills in narrow workspaces.
According to the Austrian standard RVS 08.03.04 (compaction control by means of light falling weight device) as well as the German regulation TP BF-Stb Part B 8.4 (Calibration regulations for the light and medium falling weight device) a calibration is required once a year for each device.
The Soil Mechanics Laboratory of the TU Wien is approved by the Federal Highway Research Institute (BASt, Bergisch-Gladbach) for the calibration of light falling weight devices according to the german regulation TP BF-Stb. Thus, the formal requirements of the austrian standard RVS 08.03.04 are also fulfilled.
The light falling weight device consists of a circular steel plate (∅ 30cm), which is placed on the surface to be tested. On top of this, mounted on a centering ball, is the loading device with the falling weight (10 kg), which falls onto a spring-damper element after being released by a rod during the test and thus exerts a precisely defined impact on the plate.
The plate contains an acceleration sensor and the signals are processed in the connected electronic measuring device by double integration into displacement signals (settlement of the plate), which result in a measured value (dynamic deformation modulus).
In the German regulation TP BF-StB Part B 8.3, to which the Austrian standard RVS 08.03.04 also refers, the components of the light falling weight device (LFWD) are precisely specified with their geometry, material and mass. This ensures that the devices roughly match, but within certain limits some parameters can be varied for fine adjustment. These fine adjustments are made during calibration of the LFWD. This ensures a uniform evaluation level.
Calibration is carried out according to RVS 08.03.04 (if desired, also according to the German regulation TP BF-Stb Part B 8.4). In addition, we carry out any minor maintenance work on the equipment.
Any necessary repairs of the device can be carried out after prior consultation with the client and will be charged separately. In case of defects that cannot be repaired by TU Wien, there is no claim for a successful calibration. In these cases, we recommend sending the device to the manufacturer for inspection and repair.
The TU Wien is exempted from VAT according to §2 Par. 3 UStG.
The light falling weight device (LFWD) consists of the following three components
- load plate incl. acceleration sensor,
- load device and
- electronic measuring device.
These three components form a unit in which they are calibrated and in which they are to be used for measuring in the field. Any combination of components of different LFWD is not permitted.
As part of the calibration, the loading device and the settlement measuring device (load plate and electronic measuring device) are calibrated according to the specifications of the German regulation TP BF-Stb Part B 8.4. This is also a basic requirement for calibration according to the Austrian standard RVS 08.03.04.
However, RVS 08.03.04 specifies higher requirements for the calibration, so that additionally
- an extended force measurement (additionally 60 impacts; 90 impacts in total) and
- an extended settlement measurement (additionally 6 different stiffnesses; altogether 9 different stiffnesses)
must be carried out. In addition, for a calibration according to RVS 08.03.04, the methodology for calibrating the settlement measuring device is different than for a calibration according to TP BF-Stb Part B 8.4, since the calibration factor is determined on the basis of the dynamic deformation modulus Evd and not on the basis of the measured settlement.
Furthermore, in the course of each calibration, a calibration table is generated in accordance with RVS 08.03.04, which indicates the relationship between the minimum requirement (Ev1 or Evd,ref) and the display value (Evd) shown by the respective LFWD. The correlation shown compares the method-specific (different measurement procedures, different number of tests, etc.) minimum requirements. It should be noted that the table does not describe any correlation between the measured values of the two measurement methods (Ev1 of the static load plate test or Evd of the dynamic load plate test) and must not be used for this purpose.
To avoid longer waiting times, we ask you especially in the months of January to April to make an appointment before delivery of the equipment!
We will gladly add you to our waiting list. Depending on our workload, the calibration of a functioning device takes place within 1 to 3 weeks after delivery.
To make an appointment or if you have any questions about calibration, please contact:
Ing. Andreas Hausenberger:
or send us an email:
You can either deliver your light falling weight device to us personally or have it delivered by parcel service.
Our address, a map and our opening hours can be found in the right column and below.
Location of Soil Mechanics Laboratory
Soil Mechanics Laboratory, TU Wien
TU Science Center Arsenal
Institute of Geotechnics E220-02
Lilienthalgasse 14, object OC / Gate 2
Location and access map of soil mechanics laboratory
© TU GUT & Institute of Geotechnics
Monday - Friday from 8 am - 12 am and 0:30 pm - 15:30 pm
outside these hours only on appointment
Contact Soil Mechanics Laboratory
Calibration of Light Fallwing Weight Device
Ing. Andreas Hausenberger:
Ing. Andreas Hausenberger:
Dipl.-Ing. Dr.techn. Roman Markiewicz: