Over-vibrated concrete

[Devstruct]

I have designed a industrial motor base support. The structure is composed of a concrete pedestal, supported by a concrete slab on steel beams.
The crux of the problem is that there is an existing motor adjacent to where the new concrete will be placed, which produces noticeable vibrations. This existing motor cannot be shutdown for the concrete placement. I am slightly concerned about the vibrations over-vibrating the concrete and causing segregation.
Is there any literature about quantifying how much vibration is too much? (frequency amplitude)
I have thought about requiring the use of test cylinders cured in place prior to the actual pour, but are there any other measures (additives or mix design) that could help ensure segregation does no occur?
Thanks for your thoughts!

 

[SlideRuleEra]

I have designed a industrial motor base support.

Don't be overly concerned, concrete is very forgiving if reasonable care is used:

1) Use a well proportioned concrete mix.
2) Don't cut corners on mix 28 day design strength. For example, if 4000 psi, 28 day strength is intended, use, perhaps, a 4500 psi mix design.
3) Place concrete with a relatively low (but workable) slump. Use internal concrete vibrators in the normal way.
4) Use "strong", well anchored forms, as water-tight as practical. I would design forms to resist pressure from the full hydrostatic head of fluid concrete.
5) Make sure motor anchor bolts are properly positioned (before concrete placement begins) and are secured in place so they don't move while work is underway.
6) Most important, have a competent contractor perform the work, preferably with qualified third-party oversight and test cylinders.

http://www.SlideRuleEra.net

 

[cvg]

ACI 309R, table 5-1 gives the recommended requirements for vibration of concrete

 

[Devstruct]

sliderule,
Thanks for the re-assurance. I currently have specified a generic 4000 psi. However it will likely be a high early mix in order for them to set the motor early. My understanding is that the mix will hit 4000 for the 7 day test (maybe sooner) and end up a lot higher for 28 day.
The slump is currently spec'd at 4 in. I'm thinking I should tighten that up as well.
As for the contractors qualifications and formwork, I don't have any control over them.
CVG,
I came across the ACI 309 in my googling, I haven't bought a copy yet, but it looks like a great place to start.
My initial thought is that as long the the adjacent motor vibrations are significantly removed from the recommended vibration for consolidation, I should be in the clear. Is that a reasonable assumption?
Thanks again for the responses!

 

[cvg]

without any data on the motor vibrations, it is hard to say. however, I believe it is unlikely that the motor is vibrating with enough energy to affect your work which is several feet away.

drilled cores from your pedestal could be obtained and checked for segregation and strength