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MAJ : 19/04/2010

Video topics: Pavement, Control, Continuous assessment, Subgrade, Measure, Module, Wearing capacity, Sub-layer, Earthworks

Standard: DVD
Version: French
Duration: 4 min

The portancemeter measures continuously at 3,6 km/h the bearing capacity of a subgrade (support of pavement).
It evaluates the stiffness of the auscultated structure and thus provides invaluable information for the Quality control of the design of the upper layers. The range of the modules concerned is between 30 and 300 Mpa for a depth of action of about 60 cm.
The layer of material is investigated by a vibrating wheel of low measuring width.
This measurement makes it possible to know the vertical components of accelerations of the vibrating and suspended masses, dephasing between the vertical amplitude of vibration and the centrifugal force applied to the wheel.
An associated calculation algorithm (double integration of the signal of vertical acceleration) determines the vertical effort requesting the soil and the corresponding deflection.
This method makes it possible to evaluate the modulus of deformation of the material.
The vibrating wheel being drawn at slow speed, measurement is repeated at each request (30 Hz) and the machine establishes permanently the profile of stiffness of the platform on the selected course.

Realisation: Jean-François RINGOT
Editor: LCPC
Illustration: Michelle Toujeron
Production: LCPC
Dissemination: LCPC
58, boulevard Lefebvre 75732 Paris cedex 15
Telephone number: +33 1 4043 5198
Fax: +33 1 4043 5142 / +33 1 4043 5498
E-mail : cav@lcpc.fr  
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