"Strength" glulam 115x115?

[LeffeA]

A pergola doesn't bear any snow at all, does it?
It's not a roof, just slats.

Oh yes.
The neighbor built one of those slatted roofs and then put a tarp on it to protect against rain.
It stayed until winter and then a lot of snow. Crash.

 

[Mikael_L]

Västervik is in snow zone 2.5 - 3.
If the pergola is intended to bear snow load, the beam must be replaced from 115x115 to something like 90x360 standing. I haven't calculated it now either. But I'm completely sure that under 90x270 it won't work, but I guess you'll end up with 90x325 or 90x360.

 

[Per Sandwall]

Västervik has snow zone 2.5 - 3.
If the pergola is intended to bear snow load, the support beam must be replaced from 115x115 to something like a standing 90x360. I haven't calculated now either. But below 90x270 I'm completely sure it won't work, but I guess 90x325 or 90x360 is what you'll end up with.

Thanks. I think we can disregard the snow load since it's just sparse slats as the roof.

 

[myrstack]

OK Västervik. Not much snow there.

In those areas, it's more important to count seagulls per meter of railing than snow load on everything visible from the water.

 

[Pasjostrom]

Yes, what span will it be?
In the picture, it seems to be maybe 2-2.5 meters, surely a 45x45 can manage just carrying its own weight that?

However, it's a bit difficult to find a 45x45 beam in such a quality that it doesn't twist and warp.

A 45x45 with a span of 2-2.5m will definitely hold, but in a year or so as you wrote, it will have twisted and sagged downward so that it's "visible". I have a neighbor who built a fence with horizontal slats of 45x45 and it looks ridiculous now a few years later.

 

[justusandersson]

It is perfectly fine to use 115x115 laminated timber beams horizontally. The maximum deflection due to its own weight (7 kg/m) will be at most 3 mm if the span is 4.3 meters. If you apply the same requirements to the 45x45 (C 24) ribs, their span should not exceed 2.3 meters. It can look very nice. It is important to remember that all the timber is outdoors and therefore has reduced strength properties compared to normal. The critical question is how to create an attractive junction where three 115x115 meet!

 

[Bernieberg]

It can be styled nicely like this:




Or for the really stylish like this :

 

[Plupp 282191]

Hand cut and machine cut seem like a decent challenge...fogsvans?

 

[Bernieberg]

Hand cut and machine cut seems like a decent challenge...hand saw?

Good eye measurement and a sharp Morakniv and it's done in fifteen minutes

 

[Mikael_L]

45x45 (C 24)

If you find C24 in 45x45, these are likely of significantly better quality than regular 45x45, so they may not twist as badly.

Could the TS consider 70x70 instead of 45x45? (if it's a square cross-section that is desired).

 

[Bernieberg]

Would suggest glulam for the "ribborna" as well just to maintain the shape somewhat decently. There is a glulam post 58x58x2400 mm that should fit well.

 

[Per Sandwall]

It works perfectly fine to use 115x115 glulam beams horizontally. The maximum deflection due to self-weight (7 kg/m) will be at most 3 mm if the span is 4.3 meters. If you apply the same requirements to the 45x45 (C 24) slats, their span should not exceed 2.3 meters. It can look very nice. You must keep in mind that all lumber is outdoors and therefore has poorer strength properties than normal. The tricky question is how to make a nice joint where three 115x115 meet!

Thank you very much for the informative response!

 

[Per Sandwall]

It can be met nicely like this:

[image]

Or for the really slick one like this :

[image]

Wow! Now we're talking!

 

[Oskar Öhrström]

In the process of starting a similar project and wondering how it went for the thread creator with this project? Did you stick to the original plan and was the outcome good?

 

[Per Sandwall]

Hi!

Yes, I stuck to the plan and so far everything looks as intended.

Attaching some pictures.

Good luck!