Strength classes for threaded rods?

Mogg · 27 Oct 2018 at 5:34 PM

I need a number of threaded rods at 10mm to secure a carrying beam and these should preferably be stainless.

But I don't understand the strength classes. I assume that places like Jula and Byggmax have the cheapest and worst..? What should I look for if I want slightly better threaded rods?

Chaly · 27 Oct 2018 at 6:17 PM

I think this one will do...

https://www.tools.se/produkterSe/fa...tang/Gangstang-HGS-12.9-ANS-OBH-2299829-sv-se

Peter2400 · 27 Oct 2018 at 6:37 PM

I actually don't think there's a big difference in the stainless steel rods; as long as you, as a man, slightly over-dimension them, they will hold up well.
What dimensions are you considering?

erkka · 27 Oct 2018 at 6:46 PM

Chaly said:
I think this one will do...

[link]

Are you kidding? Unfinished?

No, if you're using it for a load-bearing beam of pressure-treated wood, it should be stainless steel.
Vfz isn't enough either, it will start to rust because you probably need to cut the threaded rod.

I bought mine from Bauhaus. Felt like good quality.

Mogg · 27 Oct 2018 at 6:52 PM

E erkka said:
Are you kidding? Untreated?

No, if you're going to use treated wood for the main beam, it should be stainless steel.
Vfz is not good either, it will start to rust since you probably need to cut the threaded rod.

I bought mine from Bauhaus. Felt like good quality

No, untreated is out of the question. The main beam is not pressure-treated, but I have treated it myself. Additionally, it will be in a very protected position.

Expecting 10mm for the threaded rod.

justusandersson · 27 Oct 2018 at 6:53 PM

All steel that is sold, including by JULA and Byggmax, belongs to a certain steel quality with, among other things, specific strength properties. You must start from your needs and then see how many rods and of what dimension and quality are needed. I find it a bit hard to imagine how you will attach a beam with threaded rods? A beam, whether it is made of steel or wood, should have supports that can handle the vertical loads.

Mogg · 27 Oct 2018 at 7:50 PM

J justusandersson said:
All steel that is sold, including by JULA and Byggmax, belongs to a certain steel grade with specific strength properties, among others. You must start from your needs and then see how many rods and of what dimension and quality are needed. I find it a bit hard to imagine how you are going to attach a beam with threaded rods? A beam, whether in steel or wood, should have supports that can handle the vertical loads.

I was thinking of drilling holes in the cement wall and securing the threaded rods with anchor mass. I have drilled several holes in the beam and the threaded rods go through this and are fastened with nuts.

The roof beams will be attached to this beam and also to the wall where the beam is attached.

justusandersson · 27 Oct 2018 at 8:09 PM

Then I understand your thinking. However, I am not convinced that your construction is optimal. Do you have any idea about the load per meter that the carrying line should take? Do you have any picture or drawing?

rävlyan · 27 Oct 2018 at 8:46 PM

M Mogg said:
Planning to drill holes in the cement wall and fasten the threaded rods with anchoring compound.

If the support beam runs along the cement wall, it will hold, as the pressure comes from above. For anything to happen, the rods need to be sheared off (cut off at the wall), and that can only happen with several tons of pressure from above. How far apart are your rods? Don't forget large washers against the support beam; the wood sinks from the nut pressure, and it will become loose.

erkka · 27 Oct 2018 at 9:05 PM

I would choose 12mm from bauhaus. Cheaper than m10 moreover.

https://www.bauhaus.se/gangstang-profi-depot-rostfri-m12x1000mm.html

P-plats · 27 Oct 2018 at 11:13 PM

I would choose HGS FZV 8.8.
Not easy to find higher strength and the surface treatment is suitable for that type of construction.

Mogg · 28 Oct 2018 at 10:01 AM

R rävlyan said:
If the load-bearing beam is along the cement wall, it will hold, as the pressure comes from above. For anything to happen, the rods would have to be sheared off (cut off the load-bearing beam along the wall), and that can only happen with several tons of pressure from above. How far apart do you have the rods? Don't forget large washers against the load-bearing beam, the wood sinks from the nut pressure, and it will loosen.

The load-bearing beam is against the concrete wall. The wall is made of cement blocks, but I have knocked out holes that I have filled with concrete. The load-bearing beam is 5.1 meters and has 11-12 attachments for threaded rods.

On the load-bearing beam rest 9 pieces of 45x220 over approximately 5.1 meters in total (with the overhang). The span is 4.3 meters, and the roof has a slope of 17 degrees.

I don't know how to calculate the load that the load-bearing beam and threaded rods need to withstand.

erkka · 28 Oct 2018 at 12:02 PM

M Mogg said:
The support beam rests against the concrete wall. There are cement blocks in the wall, but I have chipped out holes that I filled with concrete. The support beam is 5.1 meters with 11-12 fastenings for threaded rods.

On the support beam rest 9 pieces of 45x220 totaling about 5.1 meters (including the overhang). The span is 4.3 meters and the roof has a slope of 17 degrees.

I don't know how to calculate the load that the support beam and threaded rods need to withstand

It is the shear stress that determines the dimension and number of threaded rods.

https://sv.m.wikipedia.org/wiki/Skjuvspänning

F you can calculate easily (self-weight + snow load according to snow zone). “Tau” is a constant depending on which steel you choose.

justusandersson · 28 Oct 2018 at 3:41 PM

M Mogg said:
On the bearer, there are 9 pieces of 45x220 resting on about 5.1 meters in total (including the overhang). The span is 4.3 meters and the roof has a slope of 17 degrees.

That means each roof beam represents a load of just under 8 kN (approx. 800 kg) if there can't be any snow pocket at the far end; otherwise, it could be more. If the house is located on Billingen or further north in Skaraborg, you can expect 20% higher values.
It is the maximum shear force that determines what the threaded rod can handle (plus, of course, the mounting). I think 10 mm is on the thin side. At least 12 mm, but perhaps even better 16 mm. I found a link about an expander screw that still describes the problem pretty well.
http://nfgab.se/sv/fastelement/17_stalbyggnation/SB12_expandrar/1889_pinnskruvexpander-eta/
Place the fastenings directly under each roof beam so you get no moment in the bearer.

Mogg · 28 Oct 2018 at 4:15 PM

J justusandersson said:
It means that each roof beam represents a load of just under 8 kN (about 800 kg) if no snow pocket can form at the innermost part, then it might be more. If the house is located on Billingen or further north in Skaraborg, you can expect 20% higher values.
It's the maximum shear force that determines what the threaded rod can handle (plus, of course, the attachment). I think 10 mm is on the weaker side. At least 12 mm, but perhaps even better 16 mm. I found a link concerning expansion screws that still describes the problem quite well.
[link]
Place the attachments directly under each roof beam so you don't have any moment in the bearer line.

Oh no... The way I've done it now, the attachments aren't under each respective beam..!!