Falling-weight deflectometer

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Measuring deflection in road beds and pavements

The falling weight deflectometer provides readings on structural capacity and overall rigidity of road beds and pavements.  Euroconsult Nuevas Tecnologías S.A. has two Ministry of Infrastructure approved heavy weight deflectometers (HWD).

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This equipment can be used on any type of road, with no geometrical constraints in regard to layout, and on flexible, semi-flexible, semi-rigid and rigid pavements.

The parameters obtained are:

  • Maximum deflection
  • Deflection basin

The equipment provides acoustic structural analysis for planning and prioritising reinforcement work, pavement managing systems for determining optimum conservation strategies, calculating reinforcements, monitoring and controlling quality at the construction stage, assessing adhesion between pavement layers, analysing airport runway pavements and railway track beds and subgrades, establishing zero point deflection so as to monitor changes over time and calculate remaining useful lifetime, working out expected layer-by-layer deflection at the project stage, monitoring consistency in platform stabilisation treatments during construction, transferring loads between concrete slabs and detecting gaps beneath slabs.

Operation

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The Deflectometer Impact consists of a mass, the fall has an impact on an elastic cushioning system. This system consists of a set of rubber pads, the number and elastic characteristics modulate the charge pulse shape produced, along with the contact time. This system, which is mounted on a plate, to generate a wave load on the firm that simulates the passage of a heavy moving axis.

This equipament has commissioned a series of sensors to measure vertical deflections produced in the strong wave load generated both in the center of the load plate as various radial positions at different distances from the center of it. It also has a front camera panning with coordinates x, y, z, for carrying inventory.