large pump on steel skid

[J1D]

A 500HP pump to be supported on a modular steel skid. The skid serves as a platform 2ft above grade and support of other equipment. The skid will be supported on steel piles. In the whole project, piles and skids are used as foundations, no concrete at all.

I wonder if anybody has similar design experiece. We have analysis software and experiece for dynamic analysis and foundation design for vibrating machines. But this seems very unique, I don't know what the proper way is to get mass of foundation and damping (skid is not in touch with grade).

Thanks for any advise,

 

[kslee1000]

Ask the vendor to see if the skid subjects to vibratory forces or not. I think there is dampen mechanism in between the pump and the skid. Otherwise, I don't think it is a good idea to found on steel piles

 

[J1D]

The vendor doesn't care the skid, they just provide pump package (with base frame to be filled with epoxy). The equipment will be mounted to skid at the module yard and shipped to site. I'll try to separate the pump support skid with the platform (because of the HP), but steel pile is the only choice we can use. Some damping mechanism will come from piles, but not as good as buried concrete block.

 

[civilperson]

You can get the required mass by using the soil mass contained in the perimeter of the piles, you can achieve the required stiffness by moment connections or diagonal braces. The combination can succeed without the use of concrete base.

 

[J1D]

Good idea to contain the soil in the perimeter of the piles. Any further way to contain soil? Where are he diagonal braces?

 

[SlideRuleEra]

What you are describing is very similar to elevated platform mounted rotating equipment at industrial plants. This is done very often.

However, IMHO, do not just attach the skid directly to the piling. Design a pile-supported structural platform and mount the skid on it. If you make conservative loading assumptions and use more than the minimum sized structural members (along with adequate connection details) you should be ok. Routine pump maintenance is important to keep vibration at reasonable levels.

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[J1D]

I think there will be two levels of steel frames. The lower level is the steel skid on piles directly, the upper level is to raise the foundation base up to touch the bottom of pump base frame. I'd like to use some concrete (precast) into the skid for mass.