Supporting multiple generators on elevated floor

[StrEngg]

Hi
I am designing a two storey building where the second floor will be supporting total four generators. Operation weight for each generator is 40,000 lbs and frequency is 1800 rpm. The type of structure will be concrete floor supported on concrete beams and columns. and the foundation will be pile foundation.

I am wondering whether it is good idea to break the building into 4 pieces by expansion joints (Each supporting one generator to reduce the interactions of vibration from 4 generators).

thanks

 

[SlideRuleEra]

I assume this is a skid mounted diesel powered generator. For best results, put each generator on its own independent foundation, not on an elevated floor - not even an elevated floor dedicated to only one generator. If the generator needs to be at a "second story" level, build the foundation that tall. Have the foundation support only the generator set. Vibration is a generator's worst enemy. The generator manufacturer should have general guidelines on installation, including foundation recommendations. Here is an example from Cummins, see page 6-4:

https://www.cumminspower.com/

http://www/literature/applicationmanuals/t030-ch-6-en.pdf

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[StrEngg]

Thank you SlideRuleEra. Yes, they are skid mounted Diesel powered generator. But there is no way to put them on the ground floor. the elevated floor will be 6m high from the main floor and the main floor will be used for electrical switchboard and other equipment and separate foundation for generator is not possible now. the total building size is close to the generator size.

I think you are suggesting to break the building into 4 pieces; each piece supporting one generator.

 

[SlideRuleEra]

StrEngg - I am NOT saying "break the building into 4 pieces; each piece supporting one generator." Putting a generator on an elevated floor will make vibration worse, even if the skids have their own isolation.

At this point, I DO suggest getting in contact with the generator manufacturer, explain the situation and see what, if any, structural support compromises the manufacturer can accept.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[thaidavid40]

Dividing the structure into four separate sections will at least isolate the vibrations from one generator to the other. If a tall foundation (like the one SlideRuleEra described) is not feasible, then a floating isolation-slab floor, supported on the regular second floor slab, might provide the vibration isolation and frequency absorption you will need. This is often done for laboratory floors where vibration isolation is a critical operational factor.

Dave

Thaidavid