Structural steel bearings

28 Jan 2011
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United Kingdom
I've had some steel beams specd for a first floor cavity wall. The span is 3.42 m.

Under the section titled 'Bearings' it reads:

Bearings 203 x 102 x 23 UB stiff bearing length, b1 = t + 1.6r + 2T = 36.2 mm; O/A b 1 taken as 138 mm taken as 138 mm.....

If so, I assume I would add 138mm to either side of the span?
Does that mean a bearing of 138mm?
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Ask the S.E.

We have had all sorts of bearing spec's, 100mm, 150mm 200mm etc. Some like to specify a minimum sq/mm bearing area. A beam landing perpendicular to a single leaf wall can only possibly occupy 105 mm in any case.
@ OP; not directly; those figures are concerned with the strength of the web of the beam (the vertical bit of the "I" shape) , and are a check to ensure that the bearing length of the beam is not so short as to increase the stress on the web and cause it to buckle.

It's rarely an issue for beams carrying domestic loading, and either the SE has used a spreadsheet for the calcs, or is trying to pack out the figures to look impressive and/or charge more.

The actual length the beam sits in the wall should be specified by the SE, and depends on the strength of the bricks or blocks; it's usually no less than 200mm.
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Perpendicular to a 100mm inner leaf is not unusual. o_O

Sorry for commandeering the post but I just wanted to double check this. I'm doing some work on my house and I intend to support my RSJ on a 400x100x140 pad stone on my inner leaf of a cavity wall (party wall), perpendicularly. I didn't think this was an issue (masonry and pad stone bearing checks are all ok) but I just wanted to check this wasn't unusual? I'm a (soon to be) chartered civil engineer but my background is as a contractor not a design consultant so this domestic work is relatively new to me. Thanks!
Perfectly acceptable - in fact the only way to get sufficient bearing area without cutting through into next doors'.

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