3" RSJ (Universal Beam) ?

[Swanvesta]

I have acquired two 3"x3"x13' RSJ's , if put side by side in a solid brick (no cavity) wall to support over a 8' span (patio door) would they do the job and would they meet any regs that are out there?

They were originally used as a base to move a machine on so I don't know if they are compatible with building work.

Thanks,
Swanvesta

 

[DAZB]

That would depend on the weight of wall above the proposed patio door. If you have a meter or so of brickwork and then a large upstairs window it will obviously weigh less than if you have 12ft of double skin masonry. Best thing is to ask a Structural Engineer either directly or via a suitable forum and give as much detail as possible.

 

[Shytalkz]

No wonder there's two of them: look underneath and they'll have "Noah woz 'ere" scrawled on them

No such current animal in the structural steel handbooks (or any handbooks, that I can see). As they're old ones, how would you know they haven't been used and abused and overstressed...?

Re Daz: not necessarily the case re the window openings. Depends on size, position relative to opening. No openings and true arching can lessen the load considerably per BS5977.

 

[DAZB]

I was trying to explain from the non tradesman point of view in my answer which is why I recommended referring to the relevant authority in that area. I could have gone into more depth regarding the spread of the load on the diagonals and so forth but generally speaking it does make a difference in load bearing if there is a window involved. I am sure Swanvesta will now be better informed and able to relate the query to a more knowledgeable person than us with a better understanding of it.

 

[Shytalkz]

Erm, I am an SE...

 

[jeds]

76x76x15 is a standard RSJ size. Not very big though and very doubtful they will support a house wall over an 8' span.

In any case it needs to be properly calculated. You could have more than just wall loads there. i.e. floor loads, roof loads, etc.

 

[Shytalkz]

I stand corrected, didn't thumb back far enough in my Corus book . Shows how often I use those sections...!

Interestingly, a quick calc taking a triangular load of 102 brickwork outer leaf shows that it works ok in bending and deflection.

But, as jed says, if there's floor and/or roof load to the inner leaf, to which I would add a lack of arching due to openings, then the inner leaf one is likely to fail in one or both of bending and deflection.

You need a proper calculation for both; and for that floor/roof spans and what's above it needs measuring up.

 

[^woody^]

I have had quite a few builders moan to me that the steel I've specified is "bigger than the one they used on their last job" and how come it needs to be a big section if there is less wall above

First I ask them if the wall on the last job is still up, and oddly, none of them have actually checked!

Then I mention part and point loads, and a few other terms which I don't understand, but seems to convince the builders

 

[Shytalkz]

You can cut lintel/steel sizes down quite drastically, *if* there are the conditions to allow for arching. Which can result in an apparent anomoly whereby you end up with bigger lintels at eaves level, than at first floor level.

You can explain until you're blue in the face just why that is; often I find it's not worth the effort and it's easier just to specify the same ones as required for the eaves at first floor level. They feel happier then...

 

[Shytalkz]

...and a few other terms which I don't understand...

That would be the whole concept of structural theory and analysis then, eh

 

[^woody^]

I don't work with concepts - just reality .... oh an a "magic 8" ball

 

[DAZB]

Can I borrow your 'magig 8' ball ? Then i would have known shytalkz was a Structural Engineer without being told. Does that mean everyone knows what i do for a living too because i haven't told anyone yet ?

 

[noseall]

Can I borrow your 'magig 8' ball ? Then i would have known shytalkz was a Structural Engineer without being told. Does that mean everyone knows what i do for a living too because i haven't told anyone yet ?

you are being far too sensitive Daz, these guys are great fun really.

they do think that they possess a higher station than us mere mortals though.

 

[Shytalkz]

Oh Nose, that's a bit harsh

 

[^woody^]

Ok, shall I start a new "Guess DazB's occupation" thread?

But seriously, why anyone would want to post, in an open forum that they are an SE, is beyond me

<wonders if there'll be any bites>