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Those of us with any background in construction have probably heard of parallams, also called parallel-strand lumber. They're long strips of wood shaved from the whole tree, formed up and glued under high pressure into finished forms. Weakness inherent in the wood are spread, harmlessly in small doses,
throughout the finished beam, so the finished strength of the beam is constant throughout the piece.
It makes sense to transfer this technology to bamboo, which has considerable strength, is cultivated for construction purposes already, and would yield even less waste while growing back much, much faster.
Tensile and compressive strengths aren't bad; possible necessary increases in member size would be offset by the extremely short regrowth cycle of bamboo.
While we're at it, perfectly good plywood is made from plain ol' straw here in the US, why not try that for a parallam?
Plyboo
http://www.plyboo.com/
I love their products! [Machiavelli, Jun 13 2005]
pest problem
Giant_20Panda_20Army
Good luck shooing these boys away from the building.. [ConsulFlaminicus, Jun 14 2005]
(?) Bamtex bamboo and palm flooring
http://www.bamtex.com/photo_gallery.htm
Some photos [bristolz, Jun 14 2005]
[link]
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+. Inexpensive and environmentally friendly alternative. I've added a link for bamboo plywood and stuff. |
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Thanks, Mach. I hadn't seen that one. |
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Those of us without any background in construction have, however, heard of the 'Giant Panda Army' [link] which may be distracted from vital peace-keeping missions by these tempting, bamboo-based structures. |
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<ot>I was told, by someone who claims to have been there, that the Hong Kong Hilton, at the time the tallest building in Asia (around 20 storeys, I think), was built using bamboo scaffolding.</ot> |
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I've been in construction for most of my adult life and I have never heard of Plyboo. Cool link. |
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it seems this exists already, but Welcome to the Halfbakery anywho.! |
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What [dentworth] said. Welcome to the HB! |
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We have bamboo "hardwood" floors in certain rooms in our house. They're quite beautiful and very durable. |
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Angel, I've seen those scaffolds: I won't swear to it but I'm pretty sure the scaffolds are largely supported by building structure already in place. It is impressive though to see a modern high-rise going up inside twenty stories of lashed-together scaffolding. A poetic juxtaposition. |
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I've seen blokes working on bamboo scaffolds in India too. Bloomin' hairy it looks. You wouldn't get me up there. |
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+ Good simply from the point of view that bamboo grows like topsy, so would be an easily renewable resource. Perhaps another idea might be the use of bamboo fibres to make a fine honeycomb structure in cross-section, for stronger lightweight beams. |
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I found sites that indicated Bamboo PSL's were made and tested, but I can't find very much else about them. |
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+ Maybe corn and canestalks could be thrown in as well. |
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An engineering firm once set out to demonstrate how much stronger steel and concrete beams are when compared to bamboo. |
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After several embarrasing attempts they 'discovered' that bamboo is an incredibly strong, light, semi-flexing construction material -- something that had been known for eons. |
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Not only that, but bamboo is also used to prop up floors when casting the concrete. |
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DrBob, if you looked closely, you might have seen the workers were wearing flip-flops as well. Now, I can barely walk on a flat surface with flip-flops, so it impresses me that these guys are balancing on a stick of bamboo. |
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What do you call a french guy, who wears sandals? Phillipe-Phollop. Geddit? |
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[elhigh] Genius! Lacking the ability to search and find how bamboo parallams are made, (and also after discussing such with others) I wonder how they can pull it off with bamboo being radial. |
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I did find a site indicating tests, but I and others I've mentioned this to wonder - how did they make it? A parallam made from radial bamboo growth seems difficult. I might mention, I and others also suspect this might be a future product in demand depending on shipping/manufacturing/etc. costs. |
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I am hoping that a bamboo parallam retains at least some of the strength of bamboo in its original form without the perpendicular shear problem. |
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I wasn't thinking of any thinner strips than what are already in use in existing parallams, which I believe are mostly pine, probably SYP. There are varieties of bamboo with a fairly thick wall that could yield an individual strip easily over a half-inch on a side, and that's larger than what's in existing parallams (about 1/4 inch on a side, guessing). That would keep the adhesive-fiber ratio on a par with what's already out there. |
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I agree that the longitudinal shear strength isn't what you could hope for. That would be a problem for the structural engineers to conquer, as it's certainly beyond me. Perhaps weaving the fibers in a not-perfectly-parallel orientation? |
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It is my experience that bamboo is strongly linear, seeing that I can easily split it along its length, but can't do a thing to it going across. But there are thousands of varieties, and I do have some spoons that show no signs of splitting, so it may be a matter of finding the right flavor. |
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Also, some bamboo reacts well to steam-bending, so you may be able to slit a stalk, steam it and unroll it. You'd get a sorta-triangular flat sheet, and could nest it with another piece to get a rectangle, then build that into a laminated stack. That would give some crossing on the fibers and reduce splitting. |
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Hmm, I just came up with that, and it seems like a good idea to me. |
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