RSJ lintel calculations?

[poorandbroke]

Anyone know how to calculate a correct size RSJ please?
The house is a run down Victorian(1860) semidetached '2 up 2 down' cottage built from soft red-brick with lime mortar.
The opening in the load bearing living-room/kitchen dividing wall will be 2.2 metres wide and the wood joists (7"x 3.25") in the two above bedroom floors will be part supported by this RSJ. To make matters more complicated, though it shouldn't affect the calculation, one bedroom floor is 7 inches lower than the other bedroom hence my specification of a Rolled Steel Joist which will have to have joist hangers welded or bolted to one side.
I have not yet applied for Building Regs permission as money is tight nor can I afford to employ an architect or civil engineer for the same reason, I am a time-served electrician who went bust ten years ago and this is the first house we've bought since then - I have to do all the renovation work myself but am well aware of my duty to comply with Building Regulations. Any help will be appreciated, thanks.

 

[Nige F]

Try www.buildersbeams.co.uk you might get a sizing along with a quote Don`t tell them you`re North of Watford

 

[poorandbroke]

Thanks Nige F I'll give it a gander. Btw it may be cold up here but our oil lamps are second to none and well light the way to the WC outside.

 

[markvirgo]

download a program called supabeam it has a free trial that will do what you want. select the universal collum or universal beam as the support needed not rsj as the sizes are old.

i have used this and found it worked great.

 

[poorandbroke]

Thanks markvirgo I'll look at that as well, cheers.

 

[peca27]

where can i download this 'supabeam' programme from mate?

 

[markvirgo]

you can download a trial from http://www.sda.co.uk/sbwdemo.htm

 

[Static]

The program can be used as a rough sizing guide but it will not provide you with building regs suitable calcs unless you buy the full version. Even then be sure what you input; ie loading, masonry strength etc.

 

[markvirgo]

The program can be used as a rough sizing guide but it will not provide you with building regs suitable calcs unless you buy the full version. Even then be sure what you input; ie loading, masonry strength etc.

not true, the calcs are correct for the trial, you can not print the results in the trial version so i used print screen and then pasted in microsoft paint which then allowed me to print it.

I have used this on my project and it was passed ok and the steels company had no problems making the steels.

 

[Static]

not true, the calcs are correct for the trial, you can not print the results in the trial version so i used print screen and then pasted in microsoft paint which then allowed me to print it.

I have used this on my project and it was passed ok and the steels company had no problems making the steels.

Ok, let me amend that; probably wont pass it. Sometimes BC will pass a member designs without calcs. Depends on whos checking and how much of a jobsworth they are .

Also as the software states: Do NOT use this program unless you have enough knowledge and experience to correctly assess the loads on members, the suitability of the proposed construction, the overall performance of the structure and the reasonableness of the program output.

Just be careful what you input.

 

[markvirgo]

Sometimes BC will pass a member designs without calcs.

the program does show calcs.

have you used it?.

 

[constalation]

I seem to remember that the rough check for deflection is: depth should be at least length / 17.

You can also check the BS covering weights of building materials (can't remember the number sorry) and the Approved document covering structure for the loads. This will allow you to do the calcs for the beam to give you the required I for the beam size and the reactions at each support to check the foundation and masonry compressive strength.

If this program does this please ignore this post but you could use it as a cross check.

I have also been told in the past that a rule of thumb is min of an inch of depth for each foot of span (again only a rough cross check in an typical load case)

Hope this helps

 

[Static]

markvirgo:
Yes i've used the program and yes it produces calcs with DEMO across it obscuring some of the checks, maybe im too fussy.
Ok, from his original discription of the wall it supports 2 bedroom floors, possibly a dividing wall and thus also possibly the roof. All loading onto "soft red brick" walls at ground floor level. On that assumption my main concern would be the piers and subsequent padstones. Yes you can use the prog to get a steel size as BS:449 has yet to be withdrawn, but it does not check the piers/stability etc.

constalation:
BS6399art 1 provides imposed/wind loadings on most buildings. BS648 gives dead loads (old document). Building Regs Part A gives guildance for structure which tells you to use BS5950 for steel design. All can be found in most good librarys but are horrid documents to read.

Your probably best positioning the beam downstanding at ceiling level with lower level floor beams sitting on top.

 

[constalation]

Won't the beam only be supporting the equivalent of one bedroom floor (half of one and half of the other)? Also half of the total ceiling area as long as the ceiling joists are supported on the bedroom dividing wall.

 

[novicemike]

ok here's another angle on the same question.

RSJ 3750 long, supporting (almost centrally) a chimney breast 1260 wide and 350mm deep. this is ground floor. chimney breast on 1st floor (& possibly in 2nd floor / atic) to be supported, but chimney stack has been removed.

I have no idea what weight of a chimney breast is, so hard to have load info for the software you all talking about.

but, i do a bit of work with steel, etc, and my hunch is: 300mm RSJ will do the job. A very scientific approach to the situation.

Am I right? (marks out of 10, please)