HIGH FRECUENCY EXTERNAL VIBRATORS
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VEAF
A: Weight of formwork (kg)
B: Weight of concrete (kg)
C: Constance dependent upon the consistency of the concrete
C=0.5 for walls and beams.
C=0.5 to 1 for horizontal precasts
C=1.5 for vertical pipes.
10.3. COMPACTION TABLES
Compaction tables are used for making prefabricated parts like beams, slabs… It can also be used for
compacting granular or powdery materials. By this way is possible to lose the internal air
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Compaction tables consists on a rigid base that rests on an elastic element (springs or absorbers).
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External vibrators are fixed strongly to the base.
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Accelerations between 2 and 4g should be applied to the vibrating plate depending on the type of
job.
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If you put only one vibrator in the gravitational center, it produces a circular vibration.
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If you put two identical vibrators placed equidistant from the gravitational center and rotating in
different directions, they produce a linear vibration.
Equation for calculating the necessary centrifugal force:
Centrifugal force:
Free mould:
F= C(D+0.2B+0.2A)
Attached mould to the vibrating plate:
F= C(D+B+0.2A)
A: Weight of concrete (kg).
B: Weight of mould (kg).
C: Constance dependent upon the consistency of the concrete and the rigidity of the mould. Its value lies
between 2 and 4.
D: Mass of the vibrating part, including vibrators (kg)
