Wadders
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| posted on 15/11/07 at 07:29 PM |
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Girder calculation needed
Can anyone tell me the correct size of RSJ i need to span 25' and lift 1 tonne max in the centre.
I might also use it to support a timber mezzanine floor for lightweight storage.
Also for ease of lifting it in and cost, could i castellate a smaller RSJ to obtain the desired strength.
If anyone can do the calcs i would be grateful.
TIA
Alan.
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zilspeed
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| posted on 15/11/07 at 08:10 PM |
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This will appear negative - for that I apologise.
If you need these calcs, best you approach an engineer and pay for their services. You're buying insurance and professional liability cover as
well as the calcs.
I'm not an engineer, but work in a related discipline and it is always drummed into us not to even give off the cuff advice, lest it bites us.
Just far the reasons above.
Still, you never know, some brave soul might still help you out
(Again, I apologise for my apparent negativity, but I'm sure you understand what I'm saying.)
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mad-butcher
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| posted on 15/11/07 at 08:36 PM |
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It might be some help as a rough guide but I needed an 8 x 4 H section girder for an 11 foot span when taking out the load bearing wall in my living
room.
Tony
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Wadders
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| posted on 15/11/07 at 08:45 PM |
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Fair comment, but this is locostbuilders, we know everything on here
I paid a structural engineer to spec the rsj's on my house extension, what he specced would have held up blackpool tower in the event of a
neuclear explosion, total overkill in a i'm gonna cover my arse in case i get sued' fashion. Thing is he didn't have to pay for them
or lift them into place, i did.
I can pretty much use common sense & guess what i need in this case, but don't want to do what he did and go too big, hence the castellation
question.
I won't hold anyone to anything, just wondered if anyone on here could give me some numbers as a pointer.
Al.
Originally posted by zilspeed
This will appear negative - for that I apologise.
If you need these calcs, best you approach an engineer and pay for their services. You're buying insurance and professional liability cover as
well as the calcs.
I'm not an engineer, but work in a related discipline and it is always drummed into us not to even give off the cuff advice, lest it bites us.
Just far the reasons above.
Still, you never know, some brave soul might still help you out
(Again, I apologise for my apparent negativity, but I'm sure you understand what I'm saying.)
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Peteff
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| posted on 15/11/07 at 08:58 PM |
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No as stated above.
But it's going to be a big one at 25' to lift a ton in the middle before you even think of supporting another floor with it. I had some
calcs done for a beam to support the corner of the house, cost £30 cash in hand.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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oadamo
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| posted on 15/11/07 at 09:07 PM |
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use box section bsb. i cant advise on the size as i dont want to be the one that kills you pmsl.
adam
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matt_gsxr
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| posted on 15/11/07 at 09:49 PM |
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Can't give you the answer myself, but if you search on
"beam calculations" you get various free software tools that give values.
The www.wikipedia.com gives useful guidlines too.
I am surprised no-one has spoken up, as we can all guess the application, and if it bends then you are going to stop putting weight on it. It
isn't like you are building a bridge!
I would have thought that if you do some calcs and propose a beam, then you will get people to chip in their views/experience.
Matt
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Aboardman
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| posted on 15/11/07 at 10:59 PM |
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what size of mezzanine floor is it.
I may be able to point you to a approx beam size when i get into work in the morning.
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Biggaz
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| posted on 16/11/07 at 10:20 AM |
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305x127x48 Universal Beam Should do 9.45m as a simply surported lifting beam @1 in 500 diflection
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mad-butcher
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| posted on 16/11/07 at 06:13 PM |
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discussing this wiyh a mate today and he said why not use a girder strong enough to support the mezanine and if you only need to occasionaly lift
something just put a couple of acros in place to support the beam
Tony
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