The Benkelman Beam is a simple lever arm device which measures deflection of flexible pavements under the action of moving wheel loads. A probe beam is supported by a rigid reference beam such that deflections in its 2.44m (8ft) probe end are measured by a dial indicator 1.22m (4ft) on the other side of the fulcrum. Deflections measured on a dial indicator are therefore doubled to obtain pavement deflection.
The probe beam is placed between the tires of a test vehicle, and deflection is measured as the vehicle passes over the test area to beyond the end of the probe beam. The reference beam has a leveling adjustment to zero the dial indicator. A switchable battery-operated vibrator serves as a personnel alert and assures free movement of beam parts during measurements.
The three-piece, anodized, lightweight aluminum beam is 33lb (15kg) net weight for easy portability, and the longest piece is 6.5ft (1.99m). Mechanical Dial Indicator or Digital Dial Indicator must be ordered separately.
Meets Test Methods:
ASTM D 4695