Dynaplaque 2

NF P94-117-2


Dynaplaque 2, vehicle mlpc which meets the criteria of standard NF P 94 117-2 will be used for the following applications:

• Measurement of the deformability of earthworks formation level and capping layer.

• determination of their homogeneity during construction.

• assessment of the bearing capacity and fatigue behaviour of structures such as parking lots, construction site tracks, forestry or agricultural lanes.

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The dynamic stress applied to the formation levelto be tested is similar in intensity and frequency to that caused by the passage of an axle loaded to 13 tonnes and travelling at 60 km/h. It is generated by the fall of a weight on a shock absorber spring placed on a load plate.

The soil deflection caused by this pulse and the impact force are measured as a function of time.

The combination of these two parameters during the loading phase (force build-up) in a force-deflection diagram, such as the one shown here, allows the dynamic deformation modulus of the structure at the test point to be calculated directly. The device is mounted in a fixed position on the chassis of a light vehicle.

It includes:

• the shock generator is made up of the falling weight, the maneuvering cylinder which also ensures the guidance of this weight, the damping spring block, and the triggering hooks.

• the sensors integrated in the load plate are the force sensor consisting of three highly rigid piezoelectric washers, and the non-contact displacement sensor mounted on a suspended and damped base.

• the maneuvering frame with the fork, the tilting cylinder, and the hydraulic unit.

• the distance travelled encoder for the location in the longitudinal profile.

Placed inside the cabin, the electronic system consists of:

• an interface box with the power control order for the automation and conditioning force and displacement sensors.

• a portable industrial microcomputer and an electronic box with an analogue to digital conversion card, a counting card.

• a resident software application for ordering the automation, acquisition, data processing, and display of results.

• Dynamic modulus range: 20 to 250 MPa
• Test rate: 20 to 30 per hour (3 shocks per test)
• Storage capacity: one week of intensive work
• Diameter of the load plate: 600 mm
• Falling weight: 125 kg
• Maximum drop height: 0.70 m
• Maximum force: 100 kN
• Impact time: 15 ms ±5 ms
• Displacement sensor stroke: 15 mm
• Windows environment

The second generation retains:
• Simple and fast laying by a single operator.
• High measurement rate (30 to 40 tests per hour).
• Mobility on construction sites and on the road with very fast response times.
• Immediately usable results thanks to our new software that allows acceptance reports to be drawn up remotely.
• Fixed installation on a light vehicle, preferably with four-wheel drive, to make it easier to cross difficult areas.

It also offers new benefits:
• Direct measurement of the dynamic modulus.
• Increase of the measuring range to the highest stiffness values (from 100 MPa to 250 MPa);
• Elimination of spring calibration and global calibration at various sites.

Download the Dynaplaque 2 datasheet in PDF format