adding loading to old RSJ

[Hugo Nebula]

On Wed, 12 Aug 2009 02:36:23 GMT, a certain chimpanzee, "BigWallop" randomly hit the keyboard and produced:

For a forty storey apartment block maybe, but not any normal house. A two or three storey house would need 30 minutes, flats and commercial buildings up to (IIRC) 30 metres high 60 minutes.

The pre-1985 regulations had 'deemed to satisfy' standard fire protection details in them. Thanks to the way the regulations now offer the designer more freedom to choose more innovative methods of meeting the requirements, this information has been removed, and you have to get it from the plasterboard manufacturers. They, of course would prefer you to pick their specialist plasterboards and fixing materials rather than use one board for all situations. So good luck in finding out how much standard wallboard you need to give 30 minutes fire resistance to a 7" UB.

[Tim Lamb]

In message , Hugo Nebula writes

Hmm... I don't like the sound of *commercial* buildings needing 60 mins. Is that for floor supporting beams only or would it include portal frame where the roof is the main load?

Most recently constructed *change of use* barns on farms will be BS 5502 steel portal frame.

I had planned to use Oak cladding for any supporting steel in my Victorian barn but am now concerned about meeting 60 mins fire resistance.

regards

[BigWallop]

This might help <

It's a lot of reading, but worth the effort.

[Simon]

Well, I've had a local struct eng round. I'd told him the rough details on the phone, and he was umming and ahhing about the double RSJ I mentioned before. When he found out the floor load was on the side walls and not the RSJs had said it "oh, its fine then".

He OK'd my plans for hanging one purlin off the RSJ with timber bolted to the web and jiffy hangers, and said the existing weight on the RSJ from the wall above was sufficient to overcome torsional forces. He made a lot of fuss telling me how to fit masonry joist hangers for some reason, but said to dry pack above the joist hanger flange and leave it a week before the main roof tile load goes on.

He had done some calcs after I phoned him, but only charged me for verbal advice (100 quid + VAT), and will write me a letter detailing his general advice but without calcs. If the BCO was calcs at any point, he'll get the info from his file and do the calcs for me (for another 100 quid !)

Now I need to work out how to drill 10mm holes in the web of the RSJ.

10mm thick. Best drill bit, cutting paste etc ?

Simon.

[Tim Lamb]

In message , Simon writes

Start small and work up to 10mm.

regards

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Simon saying something like:

Hire a magnetic clamp drill, and the job's much, much easier.