I am trying to improve my intelligence by actually working out the math to design an overhead rack......... it's not going well.

I would like to use 1" square tubing, 1/8" wall (probably aluminum 6031 or 6036).

The shelf will be 7' long by 1' deep. The shelf itself will be a rectangle by the above dimensions with 6 pieces to span the width (about 1 cross piece every 1'). Decking will probably be some type of open coated steel wire like below, really cheap at $7.26 for 6'.

The back 7' rail of the rack will be lag bolted every 16" to existing 2x4 stud partition wall. I will try to center it, but the likely hood is that it will be off center. So this load will be a shear load on 5 bolts at best 4 at worst. I am thinking of using 1/4" lag bolts 3" in length (1" bar, 1/2" drywall leaving 1.5" embedded into stud). The balance of the load will be suspended from overhead 2x6 trusses with 2x4 bottom chords. Square tube to angle connection with bolt and nut and then lagged into ceiling. The intent is to place 2x4 sections between the truss's bottoms and lag into these from below if perpendicular, if parallel (2) 2x4 on edge across the truss bottom chords and use threaded rod with large washer.

A lot of variables to be worked out....uh huh..but I wanted to just get a rough order to see if 1" tube is capable of what I want it do.

Estimated weight for storage - no more than 360 lbs.

I need help with deflection calculation, bending stress calculations and how to evaluate the component and then the item as a system if that is possible.

So far:

moment of inertia of the square tube = I =(a^4-b^4)/12

answer = 0.05697 inch^4

section modulus = S = (a^4-b^4)/6a

answer = 0.11393 inch^3

beam moment? = M = wl/8 using 360lbs/7ft /8

answer = 6.428lbs/ft? (wasn't sure of the units to use

after the division with "8") or in psi (x12) 77psi

this would be assuming that all the weight would bear on this one beam which is not the case, but this is where I am unsure as to how to proceed. How can I evaluate the system? Do I assume uniform loading and then apportion weight accordingly to sections?

__Materials__:I would like to use 1" square tubing, 1/8" wall (probably aluminum 6031 or 6036).

__Dimensions__:The shelf will be 7' long by 1' deep. The shelf itself will be a rectangle by the above dimensions with 6 pieces to span the width (about 1 cross piece every 1'). Decking will probably be some type of open coated steel wire like below, really cheap at $7.26 for 6'.

__Support__:The back 7' rail of the rack will be lag bolted every 16" to existing 2x4 stud partition wall. I will try to center it, but the likely hood is that it will be off center. So this load will be a shear load on 5 bolts at best 4 at worst. I am thinking of using 1/4" lag bolts 3" in length (1" bar, 1/2" drywall leaving 1.5" embedded into stud). The balance of the load will be suspended from overhead 2x6 trusses with 2x4 bottom chords. Square tube to angle connection with bolt and nut and then lagged into ceiling. The intent is to place 2x4 sections between the truss's bottoms and lag into these from below if perpendicular, if parallel (2) 2x4 on edge across the truss bottom chords and use threaded rod with large washer.

A lot of variables to be worked out....uh huh..but I wanted to just get a rough order to see if 1" tube is capable of what I want it do.

Estimated weight for storage - no more than 360 lbs.

I need help with deflection calculation, bending stress calculations and how to evaluate the component and then the item as a system if that is possible.

So far:

moment of inertia of the square tube = I =(a^4-b^4)/12

answer = 0.05697 inch^4

section modulus = S = (a^4-b^4)/6a

answer = 0.11393 inch^3

beam moment? = M = wl/8 using 360lbs/7ft /8

answer = 6.428lbs/ft? (wasn't sure of the units to use

after the division with "8") or in psi (x12) 77psi

this would be assuming that all the weight would bear on this one beam which is not the case, but this is where I am unsure as to how to proceed. How can I evaluate the system? Do I assume uniform loading and then apportion weight accordingly to sections?

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