New Pump on Suspended Slab
New Pump on Suspended Slab
(OP)
Hello!
I have been tasked with investigating the feasibility of installing a new pump (and concrete pump base) on a suspended slab operating floor. The pump is 600HP and the suspended slab is only 6" thick supported by concrete beams.
I was hoping someone may be able to shed some light on any special considerations or rules of thumb for this type of design. I would imagine that in addition to the vertical gravity loads there may be some additional vibration loads. How can these loads be quantified? Are there any standard methods to dampen the possible vibrations? Would you just use a large concrete mass typically?
Any insight would be most appreciated.
Thanks!
I have been tasked with investigating the feasibility of installing a new pump (and concrete pump base) on a suspended slab operating floor. The pump is 600HP and the suspended slab is only 6" thick supported by concrete beams.
I was hoping someone may be able to shed some light on any special considerations or rules of thumb for this type of design. I would imagine that in addition to the vertical gravity loads there may be some additional vibration loads. How can these loads be quantified? Are there any standard methods to dampen the possible vibrations? Would you just use a large concrete mass typically?
Any insight would be most appreciated.
Thanks!






RE: New Pump on Suspended Slab
...no way. For starters, expect a 600 HP electric motor to weigh over 3000 lb. Add in the pump/piping weight, a suitable mounting for both, then the dynamic forces experienced during operation.
Both the beams and the floor almost certainly will have to be replaced with more robust structure.
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: New Pump on Suspended Slab
Of more importance is the fact that the bedplate of the pump and motor are not really structural things and need to sit on concrete which doesn't flex or move.
You can also get reaction loads from the pump vendor to take into account as start/ stop and occasional loads.
This doesn't sound like a good thing to be doing.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: New Pump on Suspended Slab
RE: New Pump on Suspended Slab
If the loads are too great for the slab configuration, XR250 makes a good point. Steel beams beneath the pump running to perpendicular steel beams over the concrete beams would be a possible solution.
RE: New Pump on Suspended Slab
K G Bhatia, "Foundations for Industrial Machines."
Suresh Arya et al, "Design of Structures and Foundations for Vibrating Machines"
RE: New Pump on Suspended Slab
We are looking at a couple different locations for the pump, one where the pump would be centered on a large 14" x 34" concrete girder (running parallel to the girder span) and the other where the pump runs over top of a 10" x 20" concrete beam (running perpendicular to the beam span).
The 2nd proposed pump location is actually where there was one in the past that was demoed (similar HP). There are also several similarly sized pumps on the operating floor adjacent to the proposed location.
I would say that having the pump on the girder is the best location. Spreading the loading out an option but if we are taking the loads into the girder directly, is it really necessary (provided the girder can take the loads)?
Thoughts?
RE: New Pump on Suspended Slab
RE: New Pump on Suspended Slab
http://engineering.benabraham.com/html/compressor_...
RE: New Pump on Suspended Slab
RE: New Pump on Suspended Slab
As LittleInch and Brad805 pointed out the concern is vibration, structural support can be addressed. No doubt the pump/motor can be installed, and it will operate properly... the consequence would be much more frequent major overhauls than would be the case for a machine with a proper foundation.
Steel beams under the pump/motor solve the structural problem by distributing the load, but make the vibration problem worse. The pump/motor would now be somewhat isolated from the mass of the building. Mass (inertia block) is the easiest way to "tame" vibration. Connecting the beams to the building would not help much, the inertia block needs be almost "bonded" to machine so that they all vibrate together - at the same frequency(s).
For large elevated rotating machinery, the link that delagina provided is to the type foundation also used at electric generating stations for the turbine/generator. This massive concrete "turbine/generator pedestal" is actually designed to vibrate at the precise frequency needed to cancel out vibration of the turbine/generator operating as it's synchronous speed. That is an example of how important minimizing vibration can be for a machine expected to operate for decades.
For reference, here is the page of my website about machinery foundations that Brad805 mentioned: Link
There is one "trick" that someengineer could investigate, if the pump/motor have not been purchased:
Is the pump/motor a "Horizontal Pump" (motor shaft is horizontal) or is it a "Vertical Pump" (motor shaft vertical)?
A Vertical Pump is more tolerant of vibration issues than a Horizontal Pump. Has to do with the fact that in a vertical machine gravity is not causing the shaft to bow - even that small force can be important with machine vibration.
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: New Pump on Suspended Slab
RE: New Pump on Suspended Slab
mainly because nobody really knows how to add dynamic analysis of the pump inside an equipment structure.