Cracks under Steel Beam

[billm]

NHBC state minimum of 100mm but at the end of the day actual bearing should be confirmed by load calculations

Yep, 100mm for a 3m or 5m beam .. but for a 10m beam sat on a 100mm wide vertical padstone ?

BC also pointed out cracks bang in the centre of the blockwork along the 10m beam, so it's flexed in the middle as well.

We'll wait to see what specs he sends to BC and compare with what he fitted. It could be the builder is right and the SE got it wrong .. we'll see

 

[johnny2007]

I've personally never fitted a 10m beam, but on shorter beams (up to 6m) my SE always recommended a minimum of 200mm setting.
100mm might even be compliant, but it's one of those things that's better to over design imo.
For the sake of a few pounds in steel...
And then the blockwork and padstones need to be laid as others suggested.

 

[stevie888]

No. The whole point is not to spread the load, but to prevent local bearing stress shearing the wall directly below the beam.

Why don't lintels require padstones?

Padstones are there to spread the load imposed by the beam out over a sufficient area to match the allowable bearing stress of the masonry. Bigger loads and weaker masonry dictate larger pads..

Perfectly possible to bed a beam direct on masonry if the numbers work. This is why normal lintels don't need pads.

 

[stevie888]

I've personally never fitted a 10m beam, but on shorter beams (up to 6m) my SE always recommended a minimum of 200mm setting.
100mm might even be compliant, but it's one of those things that's better to over design imo.
For the sake of a few pounds in steel...
And then the blockwork and padstones need to be laid as others suggested.

I don't believe for one second that a competant SE has detailed a 100 bearing for such a beam.

I would always have 150 minimum and increase that if the padstone was going to be long to reduce the tendancy for the pad to roll under eccentric loading

 

[^woody^]

Because the local bearing stress does not need to be reduced to an acceptable level by using padstones at a guess?

Yes. But it's bizarre that if you have the exact same opening and loading, and put a steel beam across, building control will want padstones or a calculation on the wall bearing strength. But, if you put a steel lintel across, nothing is required. It's like magic.

 

[Dereekoo]

Yes. But it's bizarre that if you have the exact same opening and loading, and put a steel beam across, building control will want padstones or a calculation on the wall bearing strength. But, if you put a steel lintel across, nothing is required. It's like magic.

Possibly due to lintels have a stated SWL and this puts any bearing pressure with the usual specified 150 bearing within the capacity of even soft brickwork and BC know this, not fact ,just an hypotheses.