Universal Beams

[LinusIT]

Hi everyone,

I'm hoping someone can clear this up for me, I've tried to research and figure it out myself but to no avail.

I need to order 2 universal beams for my extension, I have had the calculations done by an architect. I have tried contacting him but he is always unavailable.

On the paperwork it says Section Size: 254 x 146 x 43 UB Grade 43 which is easy to understand after a quick Google. The part I'm struggling with is the length, I can't fathom this part out. Just below the Section Size statement there is:

D=259.6mm B=147.3mm t=7.2mm T=12.7mm Ix=6,540cm4 ry=3.52cm Zx=504cm3

Is the length of the beam stated in the above?

Thanks in advance

 

[freddiemercurystwin]

254 is the height (give or take a few mm), 146 is the width (give or take a few mm), 43 is the weight in KG per m run.

The actual height and width will be are determined by the weight of the beam, which can vary. Obviously a heavier (or lighter) beam is used when more loading is required.

The length is normally 300mm more than the clear span. Though often 200mm will be adequate.

Hope your architect is insured to provide calcs ........ Which your BCO will prolly want to see.

 

[oldbutnotdead]

Is the length in that lot- don't think so. There should be a drawing or section to go with those- t might be web thickness and T flange thickness or they could be the other way round. Ix looks like moment of inertia, Ry looks like radius of gyration and Zx should be section modulus. Those dredged from Strength of Materials many many years ago...... if a structural engineer has specced the beam then you don't need to care.

 

[freddiemercurystwin]

As mentioned the length the opening+300mm.

 

[tony1851]

The calcs will not normally give you a length for the beams - that's up to the builder (or client) to check. As above, usually the clear span + 150mm each side for bearings, but rarely super-critical.

BTW, those are quite hefty beams; what's the span, and what are they carrying (a first-floor locomotive repair shop, perhaps?).

 

[LinusIT]

Thank you for the replies everyone.

It does say on the plans and in the beam calcs paperwork that the beams must have a minimum 150mm seating onto the padstones at each side.

I've had an extension built at the back of my house which when the original wall is removed will make the living room bigger. The beams are supporting the first floor load and roof above that.

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• LinusIT
• 27 Feb 2015
• 1

The red line shown on the image above is 4.75m. The pillar on the right side of the opening is stated as 665mm. Does this pillar have to be that big considering the beam only sits on 150mm? There will be a door on the other side of it going into the dining room, I'm not keen on having such a large pillar in the "middle" of the room.

 

[tony1851]

The span is not that great so the beams won't be carrying particularly high loads.

Personally, I would not have built a new pier on the rhs but simply used the existing cavity wall, perhaps with a 225 (ie one brick) projection (assuming the wall is in reasonable condition). The load is soon dissipated down and throughout the wall by the bonding action of the brickwork.

On the lhs, it's slightly more problematic as you've got the return on the new cavity wall to consider.

 

[freddiemercurystwin]

Now I'm no engineer but having drawn up plenty of these types of extensions my SE consistently seems to require a pier on the external wall and the internal one can be free of a pier, or at least a lessor one than the one the OP's arch has drawn. Odd .......

Is he actually qualified and insured to do structural calcs?

 

[LinusIT]

I do plan on using the existing cavity wall as the support for the UB. The bricks and blocks are in very good condition.

My query is on how wide this actually has to be?

I think the lhs won't be a problem as what the beam sits on will be behind the extension block work. Hopefully that'll make sense.

I believe he is qualified and insured to do structural calcs. He is my builders architect. However I might add, I've sacked my builder as his work was worthy of featuring on Cowboy Builders. I have had to redo neigh on everything except redo the block and brickwork.

Some more photos showing the wall in question:

Left Hand Side:

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• LinusIT
• 27 Feb 2015
• 1

Right Hand Side:

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• LinusIT
• 27 Feb 2015
• 1