Benkelmen Beam deflection apparatus

Static pavement deflection is measured by the Benkelmen Beam (BB) which consists of a slender beam 3.66 m long pivoted at a distance of 2.44 m from the tip. By suitably placing the prove between the dual wheels of a loaded truck, it is possible to measure the rebound and residual deflections of the pavement structure. The overlay thickness required for strengthening of a given road stretch is derived from the BB deflection record and other necessary design parameters.