regrets Posted November 22, 2023 Share Posted November 22, 2023 Aluminum roof frame for orangery is bolted together without any spacers to prevent torsion. Is this acceptable? Link to comment Share on other sites More sharing options...
Alan Ambrose Posted November 22, 2023 Share Posted November 22, 2023 You mean the bolts appear to be squeezing the frame a bit out of parallel? Or it could just be a camera lens aberration / pincushion distortion thing - maybe you can confirm? Personally, I can't see that as a torsion effect as I imagine all the holes in the frame are clearance holes, so the only torsion effect would be the rotational friction on the washers. Slack off a bolt or two temporarily and see whether it goes back into parallel? Link to comment Share on other sites More sharing options...
joe90 Posted November 22, 2023 Share Posted November 22, 2023 That is bad IMO those bolts are bound to distort the frame, what does the instructions say?, best confirm this with the manufacturer. 1 Link to comment Share on other sites More sharing options...
regrets Posted November 22, 2023 Author Share Posted November 22, 2023 @Alan Ambrose I have measured the distance between the beams, it is squeezed by about 5mm where the bolts are, compared to where the weld is. If you keep on tightening the bolts at the bottom then the beams will just bend more out of place. Spacers/washers over the tension bolts would prevent this. Link to comment Share on other sites More sharing options...
regrets Posted November 22, 2023 Author Share Posted November 22, 2023 @joe90 the manufacturer refused to give me instructions because they only deal with retailers. They did say it is normal. Link to comment Share on other sites More sharing options...
joe90 Posted November 22, 2023 Share Posted November 22, 2023 Well I would not be happy with that and I would put spacers in there, if only a chunk of timber. Anyone else got a view? 1 Link to comment Share on other sites More sharing options...
saveasteading Posted November 22, 2023 Share Posted November 22, 2023 The bolts only stop the timbers from moving or bending away from each other. They don't prevent movement the other 3 directions. So yes they should be packed tightly between, or have nuts tight on the inner faces. It's so easy to do, especially at initial construction. But can still be added in a half hour. Timber to timber. Perhaps folding wedges is easiest. 1 Link to comment Share on other sites More sharing options...
joe90 Posted November 22, 2023 Share Posted November 22, 2023 (edited) 8 minutes ago, saveasteading said: They don't prevent movement the other 3 directions. They are also causing distortion ! Edited November 22, 2023 by joe90 Link to comment Share on other sites More sharing options...
regrets Posted November 22, 2023 Author Share Posted November 22, 2023 @joe90 Agreed. I will get the fitters to loosen the frame and then insert 25mm slotted wood in between the bolts. At least they won't have to remove anything and the beams will remain straight. Now, I am thinking what type of wood. Would 25mm Structural Hardwood Plywood Poplar Core work? It must be able to withstand the the pressure over time. Should I be looking at oak or teak? Link to comment Share on other sites More sharing options...
joe90 Posted November 22, 2023 Share Posted November 22, 2023 Ply would be fine. Link to comment Share on other sites More sharing options...
saveasteading Posted November 22, 2023 Share Posted November 22, 2023 1 hour ago, regrets said: what type of wood The same as what is there will do or denser. 1 Link to comment Share on other sites More sharing options...
Alan Ambrose Posted November 22, 2023 Share Posted November 22, 2023 If you measure the gap in a few places with a vernier to get a fairly accurate average - you can likely find some tubular nylon / aluminium / steel spacers off the shelf. Link to comment Share on other sites More sharing options...
saveasteading Posted November 22, 2023 Share Posted November 22, 2023 It would be best to slacken the nuts, insert packer and retighten, so the timbers compress together. Can't see, but there should be washers. Link to comment Share on other sites More sharing options...
regrets Posted November 22, 2023 Author Share Posted November 22, 2023 @Alan Ambrose Agreed Alan, it is 25mm exactly on the welds, which should be easy to find. Will have a scout around this afternoon. @saveasteading No washers or packing but this is about to change. Link to comment Share on other sites More sharing options...
saveasteading Posted November 22, 2023 Share Posted November 22, 2023 1 minute ago, regrets said: this is about to change. It's a good job you're inspecting. Link to comment Share on other sites More sharing options...
Gus Potter Posted November 22, 2023 Share Posted November 22, 2023 (edited) 13 hours ago, regrets said: Is this acceptable? I don't know as I can't see enough of the structural frame, what it is holding up and the load path from the roof down to the supporting structure. What is the span of roof you are supporting? Where in the country do you live.. London or Aberdeen.. snow loading is important. You see some behaviour that exhibits some twisting.. which is indeed torsion in broad terms... it's ok to say what you see! I think.. what is going on round about as you have timber, metal and connction bolts etc. To give a more detailed answer I would need to see more panoramic photos so I can take a view on the loads. Next I would need to see the section profiles (thickness, shape, material and grade) so I can assess what loads are going where. I would like to see if the metal profiles themselves are out of shape under load. Once I know a bit more of about that then you can start to put together the basics. It may be that the timbers you see are just there to make it easy to fix plasterboard to! In other words it may all be absolutely fine but the timber is not inherantly structural has twisted and shrunk. It may just be good design.. let's chuck in some wood as it's easier to screw / nail into! I do this all the time. I bolt timber to steel (steel comes with the holes in it, I try and make it idiot proof to some extent) so the folk fixing the plaster board etc have something easy to fix to. Or if the metal profiles are out of shape it becomes a different animal. You see some twisting. As an SE I would want to know.. is this due to lateral torsional buckling, local buckling or distortional bucking and couple that with the grade of aluminium or is it/ and a manufacturing defect. Now I have laid that on thick but to learn about this takes a Masters degree as a minimum in Structural Engineering plus further study.. so it's not bedtime reading. To be blunt few suppliers of these sections really understand what they are really doing and how their profiles interact with the rest of the structure. It's a specialist subject in the SE world as not least these are what we call thin walled sections. Post more panoramic photos and you may find you don't have a problem at all Edited November 22, 2023 by Gus Potter Link to comment Share on other sites More sharing options...
saveasteading Posted November 22, 2023 Share Posted November 22, 2023 @Gus Potter. Youve noticed what I hadn't, that it appears to be a metal kit with timber infills. I still think it needs a packer, as the earlier discussion. 1 Link to comment Share on other sites More sharing options...
Gus Potter Posted November 23, 2023 Share Posted November 23, 2023 I would like to see much more of that elevation and what is on top before making further comment. Also I'm wondering if anything we are supposed to be looking at is part of the horizontal bracing system.. @regrets if you want best input input then I think you need to post a lot more photos.. if not you need to call an SE.. for this a basic rate is £85.00 per hour can be expected. You may need to take a gamble.. if the supplier is wrong you may be able to get some / all of that fee back.. Link to comment Share on other sites More sharing options...
joe90 Posted November 23, 2023 Share Posted November 23, 2023 But, can packing the gap do any harm? Common sense says not (IMO). despite the technical knowledge supplied by @Gus Potter can squeezing two separate metal panels together with no support between be correct? What torque was used to tighten the bolts?. I am no SE, but that just looks wrong mechanically. 2 Link to comment Share on other sites More sharing options...
Gus Potter Posted November 25, 2023 Share Posted November 25, 2023 On 22/11/2023 at 23:39, saveasteading said: I still think it needs a packer, as the earlier discussion. Agree. On 23/11/2023 at 12:09, joe90 said: can squeezing two separate metal panels together with no support between be correct? Your right Joe.. not a good idea squeezing stuff together like that. Good spot both. 1 Link to comment Share on other sites More sharing options...
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