Load-bearing capacity of aluminum L-beam

[Erik Lindroos]

I am thinking of a solution with the reinforced bearer on one side and that you keep the bearer on the other long side as it is now. Just one bearer on each long side and none in the middle. Instead, all joists that run across should be continuous between the bearers. The dimension on them seems appropriate to set at 170 considering the height but may need to be doubled or set closer than cc600 to get okay deflection in the transverse direction.

When I talked about cutting the beam, I meant during manufacturing if you choose an elevated beam. Then I thought you would cut out the web (the standing part of the beam) so it gets a crescent shape unloaded and then weld the flange to it. This as an alternative to starting from a straight prefabricated beam that needs to be curved.

Don't see major problems with attachments on the short side? The steel beam can be integrated by making holes in it and then screwing into one joist, through the hole in the beam and into the next joist. Then you attach the other wood to the 170-joist that lies against the beam.

For deflection, it makes little difference if it's stainless or regular steel. Regular steel is even somewhat stiffer but marginally. I suggested stainless because everything around a pool tends to be stainless, but it may become too expensive. If you can protect regular steel against corrosion, it works just as well and might be an even more reasonable way forward.

I assume it's pretty important that the wooden joists brace the upper part of your T-profile so it doesn't buckle. Or? It feels risky to subject it to all compression stress without lateral support.

Stainless is good but expensive. 8-10 times more expensive than ordinary construction steel. So 250 kg of stainless beam probably lands closer to 100k (plus manufacturing cost). But maintenance-free

 

[Bernieberg]

I assume it's quite important for the wooden studs to brace the upper part of your T-profile to prevent it from buckling. Right? It seems risky to subject it to all the compressive stress without lateral support.

Stainless steel is good but expensive. 8-10 times more expensive than regular structural steel. So 250 kg of stainless steel beam would probably end up closer to 100k SEK (plus manufacturing costs). But maintenance-free

If you clamp the two studs on either side of the beam and attach them to the cross studs in one stud, I don't see a problem. It's the deflection that's the issue, the stress on the beam with just self-weight should be quite limited, I think.

I agree that stainless steel might be aiming too high...

 

[Huggedugge1]

I envision a solution with the reinforced beam on one side and keeping the beam on the other long side as it is now. Just one beam on each long side and none in the middle. Instead, all the joists running across should be continuous between the beams. The dimension seems appropriate to set at 170 with the height in mind but may need to be doubled or set closer than cc600 to achieve an acceptable deflection in the transverse direction.

When I talked about cutting into the beam, I meant during manufacturing if one opts for an over-height beam. I thought you would cut out the web (the upright part of the beam) so it gets a half-moon shape unloaded and then weld on the flange. This is an alternative to starting from a straight finished beam that needs to be bent.

Don't see any major problems with fastenings on the short side? The steel beam can be integrated by making holes in it and then screwing into one joist, through the hole in the beam, and into the next joist. Then you fasten other wood to the 170 joist lying against the beam.

For deflection, it matters little whether it's stainless steel or ordinary steel; ordinary steel is even somewhat stiffer but marginally. I suggested stainless steel because everything around a pool tends to be stainless, but that might be too expensive. If you can protect ordinary steel from corrosion, that works just as well and is perhaps an even more reasonable way forward.

Now I get you!!! Thank you!!! This is entirely doable and a tasteful solution for me! As for pools, acid-resistant is used, but in this construction, I believe in using anti-rust paint and some kind of topcoat.

So 12mm steel plate, built as a T with dimensions 195 high and 45 wide T. The cutout in the middle to get a 30 mm upward bend in the middle? (Hmm... How does this work with the 195*45 beam? It probably needs to be bent/adjusted similarly?)

Replace the joists with 170*45 at a CC of 45 and probably a bunch of noggings?

Is this correctly understood?

 

[Huggedugge1]

Just have to thank EVERYONE for your engagement! So incredibly appreciated!!! Thank you!

 

[Bernieberg]

Now I understand you!!! Thank you!!! This is fully doable and a tasteful solution for me!
When it comes to pools, acid-resistant is used, but in this construction, I believe in using anti-corrosion paint and some cover paint.

So 12mm steel plate, built as a T in the dimensions 195 high and 45 wide T. Cutout in the middle to get an upward bend in the middle by 30 mm? (Hmm… How does it work with the 195*45 rule? It probably needs to be bent/adapted similarly?)

Replace the beams with 170*45 with a CC 45 and probably a bunch of noggings?

Is that correctly understood?

It's a somewhat correctly understood draft at least. But I would review the dimensions a bit more.

The flange on the beam should be wider than 45 mm, at least 45 mm on each side, but it makes good use if it can be a little wider under the 170 rule.

The floor structure across should, as mentioned, be investigated a bit better so that at least there's reasonable deflection, even if more than one would wish from a regular wooden deck. And that it can hold snow. With the floor structure determined, you get a better handle on the total weight as well, so that can be considered when calculating the carrying beam.

If you beef up the dimensions, you don’t need to camber the beam but make it straight. I don't know how difficult it is to camber. Violina wrote that it becomes banana-shaped the wrong way (warps) when welding, I can’t judge that. If it’s hard to weld a straight beam, maybe you can use the banana phenomenon to your advantage if you choose a different solution.

Now I understand you!!! Thank you!!! This is fully doable and a tasteful solution for me!
When it comes to pools, acid-resistant is used, but in this construction, I believe in using anti-corrosion paint and some cover paint.

So 12mm steel plate, built as a T in the dimensions 195 high and 45 wide T. Cutout in the middle to get an upward bend in the middle by 30 mm? (Hmm… How does it work with the 195*45 rule? It probably needs to be bent/adapted similarly?)

Replace the beams with 170*45 with a CC 45 and probably a bunch of noggings?

Is that correctly understood?

 

[Huggedugge1]

If you clamp the two studs on either side of the beam and attach them to the transverse studs on one side of the beam, I don't see why there would be a problem. It's the deflection that's the issue, and I think it will be quite limited stress on the beam with only self-weight.

I agree that stainless steel is probably aiming too high…

2x170 on a span of just over 4 meters won't work. It will sway.

You mean I should "clamp" the upside-down T-profile/beam between two 194*45? No problem, but just so I understand.

 

[Erik Lindroos]

With longitudinal steel beams, I see two main options:

1. A beam at the roof's outer edge, dimensioned to bear half the load. Transverse wooden beams spanning continuously over 4.2 m. These must then be dimensioned to prevent buckling, so we're back to square one. Most likely requires closer spacing than 600 mm center distance.

2. A beam at the outer edge and one in the middle. Assume that the middle one bears half the load, so as thick as in option 1. The outer beam can be a bit slimmer, but it will still require more steel. However, significantly less load on the wooden beams, which will only be 2.4 m.

 

[Huggedugge1]

It is a somewhat accurately perceived draft at least. But I would look over the dimensions a bit more.

The flange on the beam should be wider than 45 mm, at least 45 mm in each direction, but it does a good job if it gets a bit wider under the 170-rule.

The joists across should, as mentioned, be investigated a bit better so that at least there is reasonable deflection, even if more than one would desire from a regular wooden deck. And that it holds for snow. With the joists determined, it gives better control over the total weight as well, so that it can be considered when calculating the support beam.

If you increase the dimensions, you don't need to camber the beam but manufacture it straight. I don't know how troublesome it is to camber. Violina wrote that it turns into a banana the wrong way (warps) when you weld, I can't determine that. If it's difficult to weld a straight beam, perhaps you can use the banana phenomenon to your advantage if you choose an alternative solution.

Now I got unsure. By the 170 rule, do you mean the joists between the long sides and they should then rest on the innermost flange that is made slightly larger? That is, 45 mm extending under the long side and e.g., 70 mm that the joists rest on?

 

[Huggedugge1]

With longitudinal steel beams, I see two main options:

1. A beam at the outer edge of the roof, designed to take half the load. Transverse wooden joists spanning continuously over 4.2 m. These must then be dimensioned to avoid buckling, so we're back to square one. Most likely requires closer spacing than 600 mm center-to-center.

2. A beam at the outer edge and one in the middle. Assume that the middle beam takes half the load, so just as thick as in option 1. The outer beam can be a bit thinner, but it will still be more steel. However, significantly less load on the wooden joists which will only be 2.4 m.

Yes, that's how I've understood it too. Right now, option 1 feels best. Damn, I'm so happy now!!!

 

[Bernieberg]

You mean that I should "squeeze" the upside-down T-profile/beam between two 194*45? No problem, just so I understand.

Squeeze it between a 195 on the outside and a 175 on the inside, where 175 is part of the floor structure.

 

[Bjober]

It might be a good idea to mount the beam so that it can be heat-adjusted later without the wood burning. It's much smoother to bring someone with an induction heater to adjust any sagging than to have to remove the entire beam. It sounds entirely foreign to me to cut material in an arc shape for that beam. As soon as you touch that beam with a welding rod, it's more than crooked, at least that's my experience. Any local blacksmith with a heater can bend a suitable beam.

I welded a 2.3-meter long U beam with approximate dimensions of 60x180mm, 8mm thickness. I welded 6x25mm flat iron on the flanges along the entire length of the beam. Over a 2.3-meter span, the beam had bent around 20-30mm! But no problem to heat-adjust it straight again for me, who is still an amateur in the context.

 

[Bernieberg]

Now I'm unsure. By the 170 rule, do you mean the floor joist between the long sides and they should then rest on the innermost flange which is made a bit larger? That is, 45mm that goes under the long side and for example 70mm that the floor joist rests on?

I was thinking that on the inside of the steel beam there is a 170 running along the beam. Then the cross beams that lie across are attached to this. The flange should stick out 45 mm to the left in my image but no more, otherwise it will be visible. To the right in the image, it's only good if it sticks out a bit more than 45 mm so the floor joists can also be supported by it.

 

[Huggedugge1]

It might be good to mount the beam so that it can be heat-adjusted afterward without the wood burning.
It's much more convenient to get someone with an induction heater who can adjust any sag than to have to remove the entire beam.
It sounds completely foreign to me to cut material in an arc shape for that beam. As soon as you touch that beam with a welding rod, it's more than crooked, at least that's my experience. Any village blacksmith with a heater can bend a suitable beam.

I welded a 2.3-meter long U beam with approximate dimensions 60x180mm, 8mm thickness. Welded on a 6x25mm flat iron on the flanges along the entire length of the beam. On a 2.3-meter span, the beam had bent around 20-30mm!
But no problems to heat-adjust back straight for me, even though I'm an amateur in this context.

I will purchase that service. Believe me...

 

[Huggedugge1]

I thought that on the inside of the steel beam there is a 170 running along the beam. Then the studs running across it are attached to this. The flange should protrude 45 mm to the left in my image but no more or it will be visible. To the right in the image, it's only beneficial if it protrudes a little more than 45 mm so that the floor studs can also be supported by it.

Then I understood it correctly!

 

[Violina]

Honestly..

I could easily construct this without a bunch of "fancy" calculations, simply because I have so much experience with this type of construction..

But trying to give someone a solution online that delivers the desired result, when their own attempt resulted in what's visible in this thread, seems quite difficult to me..

@Huggedugge1 I can't bring myself to read more of this thread.. But when you've come up with the solution you're considering, and have a reasonable manufacturing basis, feel free to reach out to me and I can take a look at it..

Then I'll give you my honest opinion on how difficult it actually is to manufacture it in a way that you get a structure that's both durable and fulfills the desired function..

Because as someone who has experience from "both sides", that is both as a designer and as the one who manufactures what someone else has drawn, I know how little they often understand about how things actually behave in reality..