Clipping the end of a steel / Structural Issue
- Thread starter RichA
- Start date
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Dodgy? I showed the checking SE that the shear force was within the capacity of the reduced web, so how can it be dodgy?
In point of fact, my original detail showed the web cut down by only 4"; quite why they cut it down so much I've no idea but it caused me
to re-do the figures. Don't know why they bolted it down either - completely superfluous in that situation.
Painting? ....Why bother?
Surely that’s not a real word?
Would a new top plate welded on make that any stronger? And how much is on the padstone? Looks like about an inch on my phone screen.
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L
Leofric
Tony, 1 or 2 queries on that weird looking beam end. :
what sort of safety factor was used in the calculations ?
Isn't steel painted to provide some corrosion resistance?
Why was bolting it down superfluous, wouldn't that help hold it in position ?
what sort of safety factor was used in the calculations ?
Isn't steel painted to provide some corrosion resistance?
Why was bolting it down superfluous, wouldn't that help hold it in position ?
safety factors vary depending on the type of loads, and the Code used for the design calculations.
If using the British Standard code for steelwork, the safety factors are normally 1.4 for dead load (ie the weight of walls/roof/floors/
partitions etc) and 1.6 for live loads (the weight of people/things in the building; snow load etc). This means that if you
work out the dead load as - say - 20Kn, you multiply that by 1.4 = 28 Kn before working out the stress and deflection etc
this causes on the beam.
The Eurocodes use slightly lower safety factors (1.35 and 1.5 respectively), which usually results in slightly lighter steelwork,
but that code is more complex and best suited for spreadsheets rather than hand calcs.
Painting not really necessary for unexposed steelwork in a dry atmosphere.
Bolting-down;most inspectors ask for steel beams to be 'bolted down', but if asked why, don't seem able to justify it. Under load, a steel beam
bends slightly, resulting in a very slight upward curvature at the supports. If the beam is firmly bolted to the pad, all it will do is pull
up the far side of the pad off the mortar joint, causing a small hairline crack to form at that point. It doesn't add anything useful.
If the beam was going to move (eg under a wind load on a supported wall), the mortar adhesion to the underside of the padstone would
provide no resistance to movement.
It was down to 15° because of a Velux, but the pic makes it look shallower.
interestin above about "boltin ddown" over a padstone or similar.-
in my experience with steel an timber framing the steel always has to be fixed to its timber plate.
the photo you show tony needs a supportin coursed-in masonry nib an a wall plate accordin to bco's ive dealt with - a single block wall wouldn't pass.
just saying but interestin things you have to say.
in my experience with steel an timber framing the steel always has to be fixed to its timber plate.
the photo you show tony needs a supportin coursed-in masonry nib an a wall plate accordin to bco's ive dealt with - a single block wall wouldn't pass.
just saying but interestin things you have to say.
This is another old chestnut which many bco's ask for when it's not strictly necessary. A nib messes up the wall, eg in a kitchen you have to cut units around it.
In practice, you can do the bearings without nibs (unless there are special cicumstances) and just sit the beam end on a 100 wide spreader beam
at right-angles.
These can be cut from 140 x 100 pre-cast concrete lintels, and a typical length might be 400 - 450 long, depending on the load, and the type of masonry.
There are a couple of simple calcs which can be done to prove suitability to awkward inspectors, in which case it's not up to them to say
'it won't pass'.
fair enough, i now about an have used built-instone or conc spreader beams but not on a single block wall.
as for doin calcs on the job - or even anytime for me - forgettaboutit.
last BCO's argued with - one came on the next job an made us demolish an re-build some garden walls, a variation - said they were unsafe.property owners blamed us for it.
next one had us crackin out footings - claimed we'd extended the trenches since his first ground inspection.
as for doin calcs on the job - or even anytime for me - forgettaboutit.
last BCO's argued with - one came on the next job an made us demolish an re-build some garden walls, a variation - said they were unsafe.property owners blamed us for it.
next one had us crackin out footings - claimed we'd extended the trenches since his first ground inspection.
Then you've got the wrong inspectors; private inspectors are to be preferred - they are usually more amenable than local authority jobsworths.
Vaulted ceiling?
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