Would someone please do a load calculation for me ?

[rust in the eye]

I'm curious to know the load bearing capability of a 2ft span of assumed mild steel U channel. 100 x 45mm, with 4mm web 3.5 mm flange.
I looked around the web and it made my feeble brain hurt. Hoping this is elementary for one of the members here.
Thanks in advance!

 

[PCustoms]

I'm curious to know the load bearing capability of a 2ft span of assumed mild steel U channel. 100 x 45mm, with 4mm web 3.5 mm flange.
I looked around the web and it made my feeble brain hurt. Hoping this is elementary for one of the members here.
Thanks in advance!

You building a press?

If not, how are you supporting and loading this?

Pictures/sketch will help

 

[loganb]

Yes, picture worth more then a thousand words here

Would be best if you could give the cross section like this



Need to understand what direction are you loading it. "Easy way" would be load is parallel to the B leg, like if you were pushing on the above profile from top/bottom in the orientation it's shown. Hard way would be that profile is rotated 90 degrees so the tall axis is running vertical.

Is it a single piece of metal or doubled up? If doubled ..welded or bolted?

How much does it need to support and for how long? Is this a shelf for storage or something more critical where failure is more significant or potentially injury inducing

 

[rust in the eye]

Thanks for the replies.
I am not building a press, rather I have bought a cheap one and this is what it is constructed from. Supposedly a 20t model, so the jack label reads anyway.
The channel is a U cross section(not C) of the dimensions stated. Span between the supports is just under 2' accord to mnfg literature.
I have not assembled this yet and am inclined to return it as it seems flimsy to me. Delivery man, not of unusually large stature, walked it to my door on his shoulder. I dead lifted the carton and would guess it is ~100#. The bottle jack alone has to be 15#, no?
The channel is use in vertical, the long dimension standing.

 

[OX1]

Thanks for the replies.
I am not building a press, rather I have bought a cheap one and this is what it is constructed from. Supposedly a 20t model, so the jack label reads anyway.
The channel is a U cross section(not C) of the dimensions stated. Span between the supports is just under 2' accord to mnfg literature.
I have not assembled this yet and am inclined to return it as it seems flimsy to me. Delivery man, not of unusually large stature, walked it to my door on his shoulder. I dead lifted the carton and would guess it is ~100#. The bottle jack alone has to be 15#, no?
The channel is use in vertical, the long dimension standing.

Put up a pic of it or at least a link........

 

[PCustoms]

The channel is use in vertical, the long dimension standing.

Completely different loading then what most people were thinking.

I'm assuming your 2' dimension is incorrect for such a small press. Plus the loading is primarily tension, where that profile is likely the strongest.

A pic/link/PN would be super helpful, but it sounds like you (rightfully) have buyers remorse over a tiny press

 

[rust in the eye]

My main concern is the adjustable cross beams and top beams.
20t seems like a big ask here but before I tell them to stuff it I want to be certain my instinct is correct.

 

[PCustoms]

My main concern is the adjustable cross beams and top beams.
20t seems like a big ask here but before I tell them to stuff it I want to be certain my instinct is correct.

So you're concerned about the cross pieces, not the vertical piece per your last post....

Realistically the jack is probably the weakest point, followed by the bolts.

As for the math, it gets a little complicated. Firstly the load is split between 2 pieces, then distributed by the plate the jack mounts to. You could make a few assumptions and run some basic calculations, but at the end of the day (assuming it's not completely garbage steel) it's going to bend before it fails. Assuming the jack doesn't blow a seal or just stop, the bolts would be next to go.

This design looks pretty common on a lot is small imported presses, but if you think it's a POS you're probably correct, return it.

 

[rust in the eye]

I have little confidence in it. Having done quite a few laps around the sun I've learned to trust my instinct. UPS is picking up tomorrow morning.
Another example of building the bare minimum standard (maybe) and you get what you pay for.
Cost me only a few minutes to tape up the carton for return.

 

[b-dog]

I'll give it a shot. While I despise US units, that's what I'm used to....

Ixx (I) from a CAD sketch (I assumed an internal radius of 5mm and no tapers): 2.46 in^4
Max stress (σ): 36 ksi
c (distance from neutral axis): 1.969 in
Mmax (M) = σ*I/c = 44,977 in*lbs
Length (l): 24 in
Simply supported beam with a single centered load (P); M = P*l/4 or P = M*4/l = 7,496 lbs
Assuming 2 pieces, not connected you'd get about 15 kips. However, there is almost certainly something connecting the 2 channels together, back to back, and that would increase the load carrying capacity.

Since we're already here, deflection at the proposed load of 20,000 lbs (20 tons total capacity divided by 2 channels) is easy:
δ = P·L^3 / (48·E·I) = 0.081 in - a little over 1/16"

This only looks at bending, doesn't include anything for flange or torsional buckling. Feel free to scrutinize, I'm not on the clock today.

 

[rust in the eye]

I'll give it a shot. While I despise US units, that's what I'm used to....

Ixx (I) from a CAD sketch (I assumed an internal radius of 5mm and no tapers): 2.46 in^4
Max stress (σ): 36 ksi
c (distance from neutral axis): 1.969 in
Mmax (M) = σ*I/c = 44,977 in*lbs
Length (l): 24 in
Simply supported beam with a single centered load (P); M = P*l/4 or P = M*4/l = 7,496 lbs
Assuming 2 pieces, not connected you'd get about 15 kips. However, there is almost certainly something connecting the 2 channels together, back to back, and that would increase the load carrying capacity.

Since we're already here, deflection at the proposed load of 20,000 lbs (20 tons total capacity divided by 2 channels) is easy:
δ = P·L^3 / (48·E·I) = 0.081 in - a little over 1/16"

This only looks at bending, doesn't include anything for flange or torsional buckling. Feel free to scrutinize, I'm not on the clock today.

Thanks for the brainpower.
Perhaps up to the task then but still going back. I'm imagining poor quality hardware, etc. as well. I never fully unpacked it to see the hardware but the press plates looked crappy too.