Dan
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Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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I know we have several engineers on here, so someone maybe able to assist my issue.
I have a 2 tanks, with a combined full weight of 12 tonne.
I need to sit these on 3 universal beams. They will span 5m and support load along entire length, and be 457 x 152 x 82 in size.
How can I calculate or find the compressive strength to know if they are man enough, and if they are man enough can I move down thickness to save costs?
Thanks!!
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Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
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Are the tanks butted up in the middle of the beams?
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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there will be a 500mm gap between the tanks.
if it makes any odds, 1 is 8t, 1 is 4t
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Tiger
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Registered: 12th Jun 01
Location: Leicestershire Drives:Astra VXR
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Will this help?
http://www.engineeringtoolbox.com/beams-support-forces-d_1311.html
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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I think that's more talking about bending isn't it? That's the sort of thing ive been able to find, but im pretty sure its not what I need? Thanks though.
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Tiger
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Registered: 12th Jun 01
Location: Leicestershire Drives:Astra VXR
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I found this for a single load. If the beam is supported at both ends and not in the middle, then you could apply a single load calculation to it maybe?
With a single load acting at the mid-span of a beam, the equation is Force x Length ÷ 4 = Fy x Zx. As before, force equals the highest or most critical load combination pounds (lbs). Length is the total length of the beam that is usually known. Usually, units of length are given in feet (ft) and often converted to inches. Fy is the tensile strength or compressive strength of the material as described above. Zx is a coefficient that involves the dimensions of the cross-sectional area of the member. Therefore, Zx = (Force x Length) ÷ (Fy x 4), where Zx has units of cubed inches (in3).
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Dan
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Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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The beams will be sat on a level concrete floor, so the beams are taking the load along the whole length.
My thinking, which may be wrong, is as everything will be square, the load on each beam will be 4 tonne (12t/3 beams)
4000kg across 5m works out to be 800kg/m
What I need to know is what the beam will crush up at. I would imagine its a massive amount, but I cannot find ay data.
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Dan
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Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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My beams will be supported the full length, so im not sure that will work will it?
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Tiger
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Registered: 12th Jun 01
Location: Leicestershire Drives:Astra VXR
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Ratios for local buckling can be found here: (not sure how to extract the buckling weight from the ratio though)
http://www.rainhamsteel.co.uk/products/universalbeams.asp
[Edited on 02-01-2014 by Tiger]
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Dave
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Registered: 26th Feb 01
Location: Lancs
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You're using 457x152x82 ub's?
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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Yea Dave. Well. That's the size that sounded and looked good. Till we see the price.
Now they want to try use a thinner beam. So that cost is reduced.
So if I know how to work it out. I can see how thin we could go before risking it etc.
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Dave
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Registered: 26th Feb 01
Location: Lancs
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That's a massive beam for 12t, especially when it's fully supported. I bet you could sit 12t on some 178's with no drama.
Different scenario but I just used 2no 457x152x52ubs, spanning 4m to support a 3 story external wall.
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Dan
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Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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We need the height of the 457 beams, so that there access to the underside of the tank. Ideally 500mm, but the company supplying has said 457 will be ok.
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Ellis
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Registered: 11th Sep 07
Location: Aberdeenshire
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So, are you looking to confirm that you won't locally buckle the beam flange at the points of contact?
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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The center part buckling locally is the part if worry about bending.
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Ellis
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Registered: 11th Sep 07
Location: Aberdeenshire
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I'd put my bank account on that being fine however I see the issue in presenting to your client. I use 254x254x73 to sit 10te containers supported at the corner blocks only with no issues.
I can't see a way of doing this with standard hand calculations. Seems a little extreme but could you model it up and check the beam web through FEA?
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Ellis
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Registered: 11th Sep 07
Location: Aberdeenshire
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Unless you isolate the beam flange and assume it to be a piece of flat bar up on end. Use load case from 8te tank with UDL across section area of 'flat bar'. I'm convinced it would not fail even with this worst case assumption.
EDIT: I'm getting just over 1MPa for the case above...
[Edited on 03-01-2014 by Ellis]
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Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
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Well, the gaffer has been and spoke to the local steel company today, and asked there opinion. They reckon 457x152x52 will be more than capable of supporting it. But they would recommend some webs being welded in to prevent any possible twist due to high winds etc.
Im sure there must be a calculation to work it out, but seems hard to find.
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