Montano is super expensive... Call the steel dealers in your area. If you're lucky, someone will have your exact dimension. That will make it cheaper.
Keep in mind that you need double 45x195 along the entire length, i.e. just over 4 meters. But check with Swedish wood... I don't even know if double screw-glued 195 is enough.Huggedugge1 said:
I don't know much about this, but I think you should have a wheel on the floor at the end that gets stuck and a board as a rail under the movable part. Then why not take a glulam beam with sufficient dimensions at the weak end and just let it go towards the stairs, not underneath. It can become like a bench when the ceiling is closed; glulam is quite inexpensive and not so heavy. Self-supporting sheet metal also works; it can probably be ordered in full length, check e.g., Borga sheet metal.
You're welcome! Nice to bring out the tables again
Yes, around 20 ksek seems about right (the price information I found was 38.8 kr/kg + VAT).
Honestly, I'm not sure where the best balance lies in terms of the number of beams, especially after I "realized" that one side has support (as others have pointed out).
In principle, you can handle the span of 8.4 m with one beam on the cantilever side since the other side has support. BUT, it might be a bit difficult to manage the shorter span of 4.2 m with just wood beams without too much deflection. That would need to be recalculated. 4.2 m is quite a lot for 195 x 45. In the middle, you have to add up both deflections, which you can see on the current construction.
Besides thinking a bit more about the number of beams, you could possibly optimize the choice of beam type. An IPE beam is lighter but might be harder to pre-bend (if you want that). Pipes seem to be @Violina's favored option for easy pre-bending.
A bit more table-checking and calculating here too.I'll see if I can/dare to come up with more suggestions.
Finally, it would be great if someone could check my calculations!
Now I've finished eating I like what you have come up with.
I agree on two load cases:
-Opening the roof with only dead weight as load and requirements on deflection. Long side free and support along the other three sides.
-Closed roof. Support along all four sides. Should primarily withstand some snow load at least. But I suspect it's not furnished and used as a dance floor, so all comfort requirements regarding deflection might not need to be met.
Perhaps it's easiest to start with the crossbeams and see what's needed there. Should be possible to manage something sensible with a 4 m span, I think, but it probably requires doubled beams and perhaps closer than cc600. If it works well across, more focus can be put on the main beam on the long side. As mentioned, only one side needs to be able to hang freely.
I like what you have come up with.I agree on two load cases:
-Opening the roof with only dead weight as load and requirements on deflection. Long side free and support along the other three sides.
-Closed roof. Support along all four sides. Should primarily withstand some snow load at least. But I suspect it's not furnished and used as a dance floor, so all comfort requirements regarding deflection might not need to be met.
Perhaps it's easiest to start with the crossbeams and see what's needed there. Should be possible to manage something sensible with a 4 m span, I think, but it probably requires doubled beams and perhaps closer than cc600. If it works well across, more focus can be put on the main beam on the long side. As mentioned, only one side needs to be able to hang freely.
Could calculate it, but since my gut feeling from the start said that two pipes 200x100x6.3 with a little pre-curving (to hopefully result in close to 0 deflection) was "just right," I don’t feel it’s really necessary...E Erik Lindroos said:You're welcome! Fun to bring out the tables again
Yes, around 20 kkr it seems (the price information I found was 38.8 kr/kg + VAT).
Honestly, I'm not sure where the best balance lies regarding the number of beams, especially after I "realized" that one side has support (as others have pointed out).
Basically, you can manage the 8.4 m span with one beam on the unsupported side since the other side has support. BUT, then it might be a bit hard to handle the shorter span of 4.2 m with only wooden joists without too much deflection. That would need to be recalculated. 4.2 m is quite a lot for 195 x 45. In the middle, you have to account for both deflections. Which you can see in the current construction.
Besides thinking a bit more about the number of beams, one might possibly optimize the choice of beam type. IPE beams are lighter but might be harder to pre-bend (if that’s the intent). It seems like @Violina thinks pipes are easy to pre-bend.
I'll see if I can/dare to come up with more suggestions.
Finally, it would be great if someone could check my calculations!
Here, I let my professional experience (and laziness) take over.
Could you clarify what you mean? Do you mean a longitudinal batten that is screwed with a through screw + nut (through the entire pipe)?Violina said:
Regarding the pressure-treated wood, if you're thinking about corrosion, I'm not sure if rust-proof paints are sensitive to it. Galvanized sheets are not supposed to be in contact with pressure-treated wood according to the manufacturer.
My only objection is that the middle pipe will take half the load and must be dimensioned for it (it shares half the load with the outermost pipe and shares the other half with the one that has support). The big advantage is, of course, to halve the span from 4.2 m to 2.4 m for the wooden beams. Also, the outer pipe can be thinner (a quarter of the distributed load).
Agree with the calculation.E Erik Lindroos said:
If we assume that only one load-bearing beam is needed, the goal is thus a moment of inertia of about 2000 cm^4 if steel of 15 mm is a reasonable deflection.
This ended up in the wrong comment:
Regarding the pressure-treated wood, if you're thinking about corrosion, I don't know if anti-rust paints are sensitive to the chemicals. Galvanized sheets should not come into contact with pressure-treated wood according to the manufacturer.