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Re: 10 story wood building

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Fire code ?

-gm

On Thu, Mar 10, 2011 at 8:47 AM, David Merrick, Structural Engineer, Merrick Group <mrkgp.se@gmail.com> wrote:
This subject referred to the article

http://www.forintek.ca/public/pdf/Special_Pub_Order_Form/SP52CrossLaminatedTimber_the%20boook.pdf

The 10 story project is a flag ship to promote uses to cut down soft wood forests. Increasing strength with fiber orientation and glue.

With out the "cross-grain crush-able zones" the shrinkage is not as much of a problem, but the assumed wood redundancies and ductility are lost and need to be removed from the design guides for those type of wood structures.

Dynamic analysis of wood framing results in high periods and lots of ductility witch greatly reduces the seismic base shear for a wood 10 story building. But so it does for the two story building. Wood design guides assume one is not performing a dynamic analysis. Or do they? Technically the code does not disallow reduction of base shear by dynamic analysis for wood framing.

Green? Why not Bamboo?

Fast or slow growing trees have a wast of 20% for the woody roots lost when harvested and returns the carbon to the air through decay.

Harder woods even have a higher strength when used in manufactured members. The ratio of strength to years to grow are probably close to a constant.

Hard woods take 30 years, soft wood 10 years well...but bamboo takes 3 years. After the die off, bamboo roots survive to grow the next harvest. Bamboo is much stronger than most evergreen tree products, hard or soft, and so will be the manufactured bamboo fibers and glue systems.

I would rather see our forests remain to develop into old forest growth and I eager to see start ups of bamboo farms and added bamboo wind-rows for other farming uses. Bamboo grows in cold regions and alternatively can be used as light weight poles for fencing and temporary construction shoring.

Because of the future competition of Bamboo products, If Canada and US want to promote harvesting of our forests, they would be better off focusing on whole cut timbers. Today corporations are starting 100,000 acre farms around the world. China exports bamboo plywood and manufactured beams of bamboo, albeit, for now, for boutique green purposes that keep the prices high.

Fascinating is that specific bamboos, every 100 to 200 years, will simultaneously bloom and then all die, saving the root, leaving 3 years of no product. They all do it together, no matter how far apart or variant the climates. No product for about 2% of the time. It has been theorized Asia plagues may correlate with these dyings as new housing is stopped for 3 years and the bamboo fruit feeds the rodents.

New bamboo shoots achieve a complete mature length and diameter in 3 months and then reach a maximum strength in 3 years. This assures continuous shade and wind protection uses.

I watch truck loads of our forests as manufactured construction elements to be used for our wood designs and wonder why is that not of bamboo?

David Merrick




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