Timber into web of steel

[Chaser]

My builder is about to start holding the back of the house up with a pair of 356x127 UBs. These will be bolted together however, the joists run to the wall so the plan is to bolt timber into the web with hangers on it to take the first floor. Due to the size of the beam and the fact that upstairs is a tiled bathroom, I'm likely to end up with a 100mm downstand.
What size timber will be needed for the infill of the web? It's 311mm deep so am I correct in thinking the only option is a 300x47 ?

 

[^woody^]

Timber as deep as the joists.

 

[Chaser]

2 X 150s?

 

[tony1851]

Why in God's name are you using 356 x 127 UBs?????

 

[noseall]

I'm trying to work out how you bolt a timber into the web AND bolt two steel beams together - of that size. It's going to be interesting trying to line everything up.

 

[Chaser]

Why in God's name are you using 356 x 127 UBs?????

Because the SE has rightly or wrongly, requested it.

 

[Chaser]

They are 33s so lighter per length but still a challenge to get in I'm sure.

 

[tony1851]

What's the span?

 

[Chaser]

What's the span?

6.3m

 

[tony1851]

6.3m

Personally, I'd say the section size is unnecessarily deep for that span. A 254 x 254 column section (an 'H' on its side) would suffice. Admittedly it would be heavier (73kg) but they can be spliced in two sections and bolted in position. While there would be the cost of the splice, you will also have the cost of fixing your beams rigidly together - have they specified spacer tubes or a more rigid connection detail so that the beams actually work together?
A 254 x 254 would also give less deflection than the 356 beams.

Anyway, you are where you are.

As above, for fixing timber into the web, you bolt it, but you will need a reasonable number of fixings as presumably the timber will not be partly-supported off the bottom flange (ie it will be higher up on the web). How you actually arrange the fixings depends on how the two beams are to be fixed together. Your SE should really advise on this because it's part of the structural arrangement.

 

[^woody^]

The biggest "cost" of that deep beam is the eventual stupid protection below the ceiling line. Beam design is not just about it holding up the walls.

Edit:
Projection! Projection!

Protection is not stupid.

 

[John D v2.0]

stupid protection below the ceiling line

I stared at that for a while thinking you need special plasterboard for fire proofing until presumably you mean "projection"

 

[^woody^]

I stared at that for a while thinking you need special plasterboard for fire proofing until presumably you mean "projection"

You win Star of the Week.

 

[John D v2.0]

You win Star of the Week.

Aw that means a lot from you woody