replacing a 35-year-old walkway to a jetty. It is currently 10 m long and consists of two telephone poles with decking. Worked great but is starting to give up.
It is freely attached at both ends
It should perhaps support 3x100kg men standing in the middle at most.
1, tips on beam and dimension?
- Order impregnated wooden beam? Dimension? (Can't find any good telephone poles now)
- use galvanized steel beam? Type and dimension? Want to be able to attach nail board to it
It is freely attached at both ends
It should perhaps support 3x100kg men standing in the middle at most.
1, tips on beam and dimension?
- Order impregnated wooden beam? Dimension? (Can't find any good telephone poles now)
- use galvanized steel beam? Type and dimension? Want to be able to attach nail board to it
Check with the power company, they replace poles at regular intervals. If they contain creosote, you might not get any, otherwise, they aren't impossible. Then mix cold tar with some kerosene/varnolen/white spirit or another oily liquid and apply it. It will smell, but what does it matter?
Fun problem! The question is what criteria to use for the dimensioning? I think the crucial question is what deflection to accept with 3x100 kg? The only realistic option is pressure-treated glulam, due to the large span. It's clear that steel can be used, but it would be more expensive and heavier.
If you choose glulam 210x360, 3x100 kg gives a deflection of about 6 mm. The deflection due to its own weight is negligible, and due to snow (snow zone 2) about 1/500 of the span. A 90x540 beam would be cheaper and somewhat stiffer but also significantly higher. In steel, to match this, you would need an HEA 220. Each of those weighs about 500 kg. Nothing is set in stone. Am I perhaps setting the requirements too high?
If you choose glulam 210x360, 3x100 kg gives a deflection of about 6 mm. The deflection due to its own weight is negligible, and due to snow (snow zone 2) about 1/500 of the span. A 90x540 beam would be cheaper and somewhat stiffer but also significantly higher. In steel, to match this, you would need an HEA 220. Each of those weighs about 500 kg. Nothing is set in stone. Am I perhaps setting the requirements too high?
Good input! Today, the posts are between diam 200 and 300. They have worked quite well so comparatively, 21x36 glulam sounds a bit overkill. It would work with three lower beams, it's good if it's not too high at the ends anyway.
What would it mean with 3 pcs 90x200? How much does such a beam cost approximately?
What would it mean with 3 pcs 90x200? How much does such a beam cost approximately?
J justusandersson said:
With three beams, I think 90x360 would become acceptably good. It is okay to taper them at the ends if you follow certain principles. Certainly to half the height. A regular "unpreserved" one probably costs around 3000 SEK. It usually always pays to ask.
If you translate a round pole with an average diameter of 25 cm and a strength class equivalent to C24 to glulam, it corresponds to, among other things, 90x290.
It becomes wobblier.