RSJ timber infill gaps

[sm_jamieson]

My structural engineers plans involved a timber infill into an old tapered flange RSJ. I cut the timber infill to be quite a good fit into the shape, but after tightening up, there is a small gap (2mm) between the timber infill and the RSJ. Is there any glue / substance that sets fairly incompressible, that I could inject into the gap so the load is not purely on the bolt holes ? Come to think of it though, new timber always shrinks, so a timber infill that is initially wedged tight would probably loosen anyway, so maybe I'm worrying about nothing. Simon.

[Tim Lamb]

In message , sm_jamieson writes

Not so:-)

I was extending an agricultural barn recently and discovered that the erectors had *sledged* short lengths of 4"x3" into the web to secure the external cladding. It had to be chiselled out.

regards

[Cash]

For what reason is this "timber infill" being fitted into the RSJ - is it to fix floor or ceiling joists too, or just to box in the RSJ?

If it's for a joist/rafter, then the usual method (in my day) was simply to place the thing inside and resting on the bottom web and use a Hilti cartridge gun to fix the thing (they were never cut to shape and never moved after a few Hilti nails had been used,

If it's to box the RSJ in without any load bearing, simply cut the thing slightly longer than the space between the webs, and using a bloody great hammer, just bash it in, and fix the covering to it - I used to use the odd Hilti nail in the centre of the timber on long runs 'just to make sure' and never had one fail (with or without the Hilti nail.

If it's for any other reason, please do tell.

Cash

[Tony Bryer]

If they started off with a properly dry piece of wood, it would naturally swell in a semi-exposed location.

[Simon]

Its to hang a joist off - struct eng spec is timber infill both sides and long legged speedy hanger wrapped over the top and nailed to both sides. Issue was - the RSJ has tapered flanges so the "rest the infill on the bottom" does not work structurally since the bottom is tapered, and the force encourages it to slide out. Question is structurally, are the bolts just there to hold the timber in, or are they to bear the force ?

I will probably knock some steel shims into the small gap under the timber, just to be thorough. Simon.

[Cash]

No it doesn't, the taper over the width of the web isn't steep enough to slide out under the weight of the joist as it's vertical load - just skew nail the joist to the bearer with a few long nails and that will hold it.

Just there to hold the timber, the web stops it from falling onto the floor and a few Hilti nails will work just as well, and a damn site quicker - and if you really want to bolt the timber on, just fire a few Hilt bolts into the steel, drill a few holes to suit those positions in the bearer and bolt the thing on. Think about it!

Not needed, but if you feel as if you need a few wedges, timber one will do, and be less likely to slip off the RSJ - remember, steel will slip off steel fairly easily!

Cash