Thread: Wood as strong as steel - new science!

Canada uses more engineered wood products than you can imagine. Prestressed engineered Glu-lam beams will span useful distances.
The University of Northern British Columbia has a 6 storey research division, all engineered wood.
The atrium in the local Prince George hospital can't be more than 5-6 stores tall but all engineered wood from the ground up.
It's really warm-looking and interesting geometries in the post and beam design.

". . .as strong as steel." In what ways? Show us all the real numbers, both mechanical and non mechanical properties.
Density isn't a good predictor of elasticity or most anything else but density.

You're right = indoor or otherwise sheltered apps are common. No way I could see that outdoors here.
This year, we swung from +47C in the shade to -30C last night.

Re Artmes comment about us having a long way to go to catch up with overseas re laminated beams etc.
We had a plywood company here in Sydney which had 2 huge clear span factories constructed 60 or 70 years ago with laminated beams. Both have been replaced with home units for the masses.
I bought some 3/8” formply from Symonds for a formwork upstand from where Wentworth Point now is.
I vaguely remember driving into their factory a 100’ wide at least and as I got out of my ute realised the huge curved beams were laminated timber.
My ply was about 30’long so they just rolled it up, tied it with some rope in the ute.
When I cut the rope back in my ‘shop it uncoiled very promptly.
Briggs was another local ply company doing interesting stuff with Coachwood ply for the Mosquito during WW11. Their early efforts with the Pom glue made from curd fell apart due to humidity, they ended up using urea I think.
H.

Bit more info re how dumb we are compared to the rest of the world.
My first post I just did from memory which as you all know tends to get foggy after 70.
If you’re interested google Ralf Symonds.
Here’s some info on the St Peters factory.
H.

Originally Posted by artme

Elanjacobs mentions LVL beams. Good things but they should only be used where they are completely protected from moisture in particular.
The subfloor structure in our home is LVL. Trouble is he beams were extended beyond the walls of the house to support the front deck. So
far things are OK but I worry about the possibility of rain getting into the laminations.

All structural plywood has to be "A-Bond" (phenol formaldehyde resin) to comply with Australian Standard, which is a waterproof bond rated for long-term full exposure. As long as the beams are able to dry fully after rain they are most likely going to be fine.

Source: http://ewp.asn.au/library/downloads/...lvl_design.pdf page 253-254

taken from Elan's link.

Note:Even though the structural plywood phenolic bond is durable, the plywood will only beas durable as the timber species from which it is made. If the plywood is going to beused in weather exposed applications or under other exposure conditions of severehazard, the durability of the timber veneers must be considered and the plywoodpreservative treated if required to meet the hazard requirement.

The above is what I have observed. The glue itself is perfectly fine, but the timber rots if allowed to get wet under the plastic the packs get shipped in. Also the beams degrade pretty rapidly if we don't process them quickly enough and allow them to sit in the direct sun and rain for months (not often the case, but sometimes the extremely bad forklift damaged beams sit and rot for years...)

I also thought there was a structural B bond made from melamine urea but that article made no mention of it.

B-Bond is waterproof for short-term exposure and is allowed in exterior ply, but it doesn't comply with Australian Standard for structural plywood
Library - Tutorials

I wonder what sort of fire ratings the glu-lam beams have.
Seems they would char on the surface rather than soften and sag.

Originally Posted by Robson Valley

I wonder what sort of fire ratings the glu-lam beams have.
Seems they would char on the surface rather than soften and sag.

There was a new building at Barangaroo Sydney which is a multi story wood building using laminated beans and apparently it was rated as highly as a steel building. Let me see if I can find the article.

Edit: here we are: https://www.google.com.au/amp/s/amp....15-gqsmrn.html

Plyscrapers!

I was thinking that for this new engineered timber to be as strong and dense as steel it would have to be made from hardwood: Not because of the inherent density or strength but because of the pored characteristic of so-called hardwood, which in botanical terms should be called pored wood or non-pored wood (for what we tend to think of as soft wood).

Balsa of course still fits into both these categories but pine does not. My thinking is that the tubes of the pored wood are better suited to become the receptacles for the additives, but perhaps that is not the case and the cellular walls absorb the enhanced properties.

Regards
Paul

One of my problems with LVLs is that when decking is nailed to it the laminations can be parted by the ingress of the nails.

This presents an opportunity for water to penetrate anse the process of rot in motion.

The porosity of the hardwoods, the angiosperms, has many qualitative differences.
Is the timber ring porous or diffuse porous? Look at the modulus of elasticity.
As for absorption, look for the vessels being occluded with tyloses.
This explains the exclusive use of the white oaks (Quercus alba) for barrels as opposed to any similar use for the red oaks (Q. rubra).

In addition to the vessels of vessel elements, there will be a species-variable mass of very thick walled xylem fibers.
What is less evident is that the xylem fibers are far shorter than the xylem tracheids of the "soft woods," the gymnosperms
and the conifers of economic importance. This is crucial to 'web-strength' with in the wood laminates themselves.

One result is that engineered wood products from conifers have excellent performance characteristics in wood design.
The longest individual conifer fibers can be as much as 3mm in length. These are found in white spruce (Picea glauca)
and Englemann spruce (P. englemannii) in the central interior of British Columbia which is a cool - cold climate.
Any conifers grown in much warmer climates ( your Monterey pine (Pinus radiata)) lacks some suitability because the fibers
don't grow as long as in cooler climates.

Originally Posted by tonzeyd

I'd be interested to know the retail price when it hits the showroom...

Reminds me of when i was shown waterproof mdf, a product called Tricoya EXDF, which comes with a 25 year in ground warranty. Don't believe even solid wood has such a warranty.
The local Gunersons store has a block of it sitting in water and are more than happy to take it out and measure it with calipers to show you its stable in water. Obviously super keen at the idea asked for the price per sheet... had to pick my mouth up from the floor.

Can't write that and not tell us.

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This is all creating quite some press (haha!)....it's now on Slashdot and Nature https://www.nature.com/articles/d41586-018-01600-6

Originally Posted by woodPixel

This is all creating quite some press (haha!)....it's now on Slashdot and Nature https://www.nature.com/articles/d41586-018-01600-6

Thanks WP

And here's a reference to the full article in Nature, a highly respected journal. Unfortunately you'll have to pay to get past the Abstract:
https://www.nature.com/articles/nature25476


Cheers

Graeme