Reinforced Concrete Equipment Pad

[Antnyt23]

I have an existing 9'x18' concrete equipment pad reinforced with #4s @24" oc both directions on 4" of 3/4" clean crushed rock with no fines with 3 pieces of equipment on it. I will be adding 2 pieces of equipment to it. What is the best way to analyze this? I'm having trouble figuring out the method and equations used to analyze and determine the adequacy of the slab.

If anyone has some suggestions please let me know.

 

[JedClampett]

Get the weight of all the equipment. Apply as point loads (or small distributed loads if you want to be real accurate) at their locations. Then analyze the foundation as a footing with loads applied at several locations. Your Geotechnical Engineering Book should have examples of a footing with several loads on it.
Or you can figure out the total upward load and treat as a continuous beam, with the equipment acting as supports. It's a little less precise, but hopefully you're not that close.
This is actually a beam on an elastic foundation, but it's very seldom done that way.

 

[Antnyt23]

sounds good thank you.

 

[Zimba1]

are the loads (ie the equipment) generating any dynamic loads eg vibrations, rotations, or movement?

 

[Antnyt23]

no dynamic loads

 

[Zimba1]

the above solution will work out fine