Deflection criteria for bulk handling machines

[mte12]

Has anyone come across lateral deflection criteria for bulk handling machines such as stackers, reclaimers, trippers, etc.
This is to check supporting structure to BS EN.
Is it the norm that deflection from machine loads only are considered, or wind load as well.
Does requirement come form standard, or vendor, or is the crane code used?

 

[human909]

I haven't dealt with such equipment so I can't offer specific advice. However....

Given the scale and the specialised function here I'd be surprised if there are codified norms. I'd say deflection requirements would be driven by the mechanical tolerances of the machinery operating over the spans. At these scales, it wouldn't surprise me that allowable deflections are loose and the mechanical components are tolerant of deflection.

Though don't forget that it isn't just deflection that matters here but its sister, vibration. If you start designing something in steel that isn't stiff enough it is pretty easy to get unwanted vibrations either from equipment or from even moderate winds.

 

[milkshakelake]

I designed supports for an MRI machine. The specifications came with deflection and vibration criteria. I heard of a laser equipment that specified wind drift criteria stricter than building code, so the whole structure had to be designed with minimal drift for that one piece of equipment. I did other equipment (not bulk handling machines specifically) where the specs didn't have anything like that, so we designed for typical deflection criteria in the building code, like L/240 or L/360. I'm not too familiar with BS EN though.

I wouldn't say that deflection from wind load is your concern. You don't have much leeway to control it. You make sure your anchorage is good, and the building wind drifts are within control. You apply the wind loads from the equipment onto your structure. Beyond that, the wind drift of the equipment itself depends on the stiffness of its supports and frames, which you can't do anything about.

 

[mte12]

Ok, thanks for responses.