Attaching timber into web of steel I beam

[dpblack]

Hi there, I've now got 2 lovely 254x146x31 steels running party wall to party wall. I need to place a 200x75 timber into the web of the steel that the joist hangers for my underslung floor joists will attach too. Only the drawing doesn't give any guidance about joining the timber into the steel and my builder has proposed bolting it with M12 coach bolts with timber washers at 800mm centres. 800mm seems a bit far apart to me and I suspect he's just trying to avoid the effort on drilling the steel.

Anyone got any suggestions?

 

[tony1851]

That seems reasonable; the bolts are only there to hold the timber in position. When the floor is in, most of the vertical load will be carried by the bottom flange rather than the bolts.

 

[dpblack]

I guess my only issue there is that I'd either need to profile the bottom inside edge of the timber so that it sits flush on the flange (which has a curve and taper away from the web) or put some packing behind... not sure which way is most common or am I just overthinking this? Just don't want a few tons of steel and timber on my head when I'm in bed one night

 

[tony1851]

Just don't want a few tons of steel and timber on my head when I'm in bed one night

That won't happen.
The flanges of the beam are not tapered but are parallel. There is a small radius where the flange meets the web, but only about 8mm.
If you want to be really correct about all this, you could run a chamfer along the inner corner of the timber before it is bolted in, though I imagine if you tighten the bolts against decent washers, it will pull in well-enough.

 

[^woody^]

Never load the flange Put the load on the web where it should be. M12 bolts or rod at 500-600 centres

 

[tony1851]

Never load the flange Put the load on the web where it should be. M12 bolts or rod at 500-600 centres

Granted that when connecting an incoming steel beam to a primary beam, the connection should be made into the web.

But on this scale, the loads are relatively small and there will not be a problem with the timber insert deriving part of its support from the flange.