Indeed, a software application we know well ;-) shows a max deflection of under 2mm at that length (assuming a 0.8kn/m uniform load with load sharing, and C16 timber) - so well in spec. I an not sure if the 2.3 m specified is the total length including the stairs, or just the existing floor. If it is just the existing floor, and adding in the stairs added another meter or so to the span, then it looks like the deflection is still in spec.
you sound optimistic. :) They cant generally stop you doing the work, but they can make it cost a couple of grand more on legal costs, and make you do it in a way that may be less convenient.
Well, theyre the experts, Im not. I just cant imagine how you could do all this work without ever causing small movements to the joist stubs, which would crack the ceiling up. But I'm no struc eng.
The rest of your points I take on board, basically I overlooked the 7" size somewhere. G luck.
Regards, NT
2.3m is the total length including the stairwell so should be OK - cheers for doing the calcs! :-)
Andy
If you have the demo of superbeam there, then you could model all of the joists. You may find that you can simply add the new joists without needing major rework on the existing ones.
... in fact ... ok just did it. (usual caveats apply)
It looks like you could leave Joist B as is, since it is not that heavily loaded (I am assuming its length is about 2m based on your diagram). Over the stairwell you could add some 175x50 joists (approx 1m long?) hung between the wall and B, and B will still be in spec.
This leaves A, which is now carrying extra load at the point where B joins it. That is now right on the limit with regard bending (if you also assume it is carrying a bit of floor load - which in reality it may or may not be carrying, due to its proximity to the concrete beside it). If one were to stick another 175x65 joist (or narrower if you want) beside it and bolt it to it, then you would be well in spec on that.
Woohoo! Cheers John. :-)
As I say, I loaded SuperBeam up. Looked through various screens. Got frightened. Closed it again. (Sorry Tony! :-) ) Hold on... Yup, tried it again and the same thing happened! :-(
I'll see how the ground lies once I've managed to rip the partition wall down between the stairwell and existing bathroom... and also lifted the boards where the bath is etc. It *might* be possible to bolt A to the concrete (along with another joist or even some steel), not sure until I do a bit more demolition though. BTW, yes - joist B is 2140mm and the stairwell is 910mm wide.
Ta!
Andy
Same for me. However, the 3rd time, I just about worked it out, at least for single horizontal beams. You add the beam, edit it and enter the various loadings. Point loads for other beams coming off it, or a uniform load along the entire length for flooring. You need to allow 2kN/m2 for the floor.
I'm not entirely sure I'm getting the vertical columns 100%, yet.
Christian.
You will probably find it makes more sense once you have seen a completed project in it! (I was in the fortunate position of having the full set of calcs produced by an architect, hence it was simple enough to go back to the program and fiddle around a bit until I could reproduce the same figures and understand what the various bits were doing).
To model a beam, start by creating one (CTRL + B), and give it a name. Then specify the loadings. First you enter a type for the load i.e. U for uniform. Then enter the load (in kN) say 0.8 for a typical floor with joists on 400mm centres (this is a linear load rather than sq area). For each load you specify you may not need all the parameters - it will vary on circumstance. Click Apply. (you can get a fair amount of info out of the help pages).
Now specify the Timber specs. Enter your beam size (175x63), C16 timber, and for a floor you can specify "load sharing". Click apply. That's the beam modelled. So for one of your existing cross member beams that connect to joist B, you would specify the length, load type "U", load (W1) 0.8. Timber as described above. Now play with the icons at the top and you should be able to display the forces on the beam and the bending and shear loads along its length.
To model a beam like B, I find the "B/F Reaction" button is handy. This lets you specify a point load on one beam by reference to another beam rather than having to copy the loads manualy (a bit like referring to another cell in a spreadsheet). Note the beam you refer to needs to be higher up the list in the project manager. So you can add the reaction caused by one end of you cross joists to B (in your case both ends will be exerting the same down force so it does not matter which). You can use the same beam to add a load to B repeatedly, just by changing the distance along the beam where it intersects (e.g. 0.2, 0.6, 1, 1.4m etc for 400mm centres).
Finally do A in the same way.
If a beam fails, then you need to go play with its parameters to see what you need to do to prevent that.
(if you need more detailed instructions than that, then drop me an email since any more here is probably going to get pretty dull for our readers ;-)
Not sure you will need to bolt it to the concrete... in fact if it is not attached then I would be inclined not so so that you don't have to start modelling the loading on that as well! When I was fiddling with the figures I found just bolting another beam beside it was enough.
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