Calculating max load of storm shelter

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The discussion centers on calculating the maximum load capacity of a 5ft x 5ft x 5ft storm shelter made from 3/8" carbon steel AISI 1018. Participants clarify that simple stress calculations (F/A) are insufficient for structural integrity, as different load types (bending, torsion, tension, compression) require specific formulas. Suggestions include overbuilding the structure for safety and reinforcing walls and corners. One contributor estimates a maximum allowable compressive load of 80.9 kN for the box. Accurate calculations depend on understanding the load application and using appropriate engineering principles.
rimmer2300
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Easy question

Have a 5ft x 5ft x 5ft structure made from 3/8 carbon steel AISI 1018 I think

What is the max load this thing can take? What's the formula?

Stress=F/A

F=Stress*A?

Do I use the Modulus of Rigidity? Elasticity? Where can I find these values?

thanks
 
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It's just a box? No, you can't just use sig=F/A...that is for loads on a surface. For structural integrity you have to get into a bit more work. Especially if it is a frame
 
Yes it's just a box

3/8" Steel welded up to connect the walls

Any suggestions where I can find the correct formulas?

Been a while since college and can't remember where all that stuff is

thanks
 
I think you should put some figure how you apply the load, is it bending, torsion, tension or compress. Different situation will have different formula.
 
My suggestion. Overbuild. Don't worry too much about the load calcs. If it is well built and overbuilt, you should have no worries. I doubt you are going to settle for a 20% factor of safety, so why not reinforce all the walls and ceiling and gusset your corners and make that baby unbreakable?
 
rimmer2300: There is not really an easy formula. I assumed there is a compressive load, P, evenly distributed over the top surface of the box. I currently got a maximum allowable load of P = 80.9 kN. Therefore, it currently appears the box will resist a compressive load of at least 80.9 kN.
 
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