Precast Concrete Forms

SELECTING VIBRATORS

GENERAL "RULE OF THUMB"

1. For 3" slump or more, vibratory force should be equivalent to weight of form and concrete in pounds
2. For 2" slump add 75% more vibratory force.
3. No slump concrete requires up to 200% more force.
4. For forms higher than 3' add 250k impact for every foot up to 6'. (For higher forms see cast in place column applications)

THE CHALLENGE

How many vibrators (pneumatic ) are needed?

WEIGHT TO BE VIBRATED

Total weight of form plus concrete 14,000 lbs

CONCRETE CHARACTERISTICS

3" slump

VIBRATOR TYPE

Select between SVRLS-5500 (5000 lbs. force) or SVRLS-4000 (4000 lbs. force) pneumatic vibrators.

FORMULA

For 3" concrete use same combined force on vibrators as total weight of form and concrete.

14000 / 5000 = 2.8 SVRLS-5500 vibrators
14000 / 4000 =3.5 SVRLS-4000 vibrators

SELECTION

Select four SVRLS-4000 for even distribution of vibrators.

USE

Vibrators are turned on when concrete is placed in form. Vibrate until form is filled and glistening surface appears on top.

PLACEMENT

Vibration force travels 3-4' radius from vibrator. Place vibrators so vibration forces overlap. Corners are usually very stiff - place vibrators on 2- 1/2 - 3' radius.