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(Popular Science)   Structural engineers around the world tout the most advanced building material that is taking the construction industry by storm and will utterly remake city skylines ... wood   (popsci.com) divider line 146
    More: Strange, structural engineers, skylines, Shoreditch, waste minimisation, Luftwaffe, tallest skyscraper, storms, Burj Khalifa  
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7961 clicks; posted to Main » on 27 Feb 2014 at 10:19 AM (26 weeks ago)   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2014-02-27 12:40:38 PM

Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.


Stupid CLT.
 
2014-02-27 12:42:06 PM

Buggar: ChipNASA:

Sent you a link to Brute Force Collaborative blog.


Interesting, thanks for posting that.
 
2014-02-27 12:42:49 PM
He said wood

img.fark.net
 
2014-02-27 12:43:10 PM

inner ted: TheShavingofOccam123: inner ted: cgraves67: pheelix: cgraves67: Fun Fact: Tokyo was once built of wood. I wonder what happened to it?
[upload.wikimedia.org image 250x233]

No need to go further than Chicago to make your point.

I could also go with London 1666, but I thought a picture of an actual city burning would be more visceral.

cause we all know that steel & concrete building are impervious
[img.fark.net image 260x194]
/visceral enough?

We also know drywall doesn't make stairways survivable in extreme conditions. Which ends up dooming thousands of people to either burning to death or jumping.

That engineer sure saved a lot of money by using drywall instead of reinforced doodads. And it made his twin penises grow ever larger.

the point is that wood is getting a bad rap on this thread.  nothing is indestructible.  wood has been used widely & forever cause it works well & it will continue to work well.  building with wood is a great way to store carbon (unless that building burns down), it regrows relatively quickly & is less toxic than many synthetic alternatives. of course it won't be nor should it be used for everything, but seeing new uses for something that has been used for a long time is a neat thing.


definitely a neat thing. you can't grow concrete. and I'm all for using alternatives that you can grow.

like someone said above, a major concern--especially if the manufacturer has no problem cheating--is the adhesives used in these materials. if the maker cheats, there better be a thorough inspection system to catch it before it ends up in buildings (chinese drywall comes to mind). also, what about outgassing.

like I said though this is an interesting alternative to carving out huge expanses of the earth to get a hold of the raw materials for concrete and steel
 
2014-02-27 12:44:23 PM

brimed03: Buggar: brimed03: Buggar: brimed03: Buggar: brimed03: Buggar: brimed03: The Irresponsible Captain: Interesting. Personally, I'm hoping that laminate beams will revive timber frame construction. The solid wood panels have some advantages that were missed. They insulate better than steel and wood, they flex more than concrete without breaking.

Without knowing what I'm looking for, all I could find for sure on Google was laminated beams.  Could you provide a relevant link?  I'm interested.

You poor thing, you can't find CLT?  Just do a GIS for CLT and you'll see a few diagrams and pictures that will help you more easily recognize it in the future.

The fun part is knowing that, before posting, you did exactly that just to make sure you didn't sound like some jerk idiot.

/didn't work

Well you were obviously searching for it in the wrong way.  Don't get mad at me cause you're looking in all the wrong places.

I had Google-searched "cross-laminated timber."  Forgive me for not being so bright as to think of using the less-specific abbreviation.

Don't be so hard on yourself. CLT isn't obvious, it's not that any of us are necessarily less bright.

Again, the results of Googling CLT.  For those who learn best by endless repetition.

But go on, enjoy your nice cup of smug.  It'll keep you company while you wait those 16+ years to see the clt in person.

I told you to GIS. Just plain googling doesn't work.

Yeah.  I know.  So you  told me with a punchable mouthful of snark.

Who the hell would start out with a GIS search for something they want text information for?  I wanted to know what the stuff is, not just how it looks.  And you know what: I actually have pretty good game when it comes to Google-fu, and eventually I find what I want.  But why the fark would I do that when I can come back to this thread and ask someone with a relevant background who could either tell me directly or give me some solid educational/industry links?  Go GIS that one, jackass

.

Well have a nice day.  Enjoy your new found knowledge that sometimes the obvious way is not always the best.
 
2014-02-27 12:44:26 PM

John Hopoate: muppet builder


HEY!

/that's hilarious
 
2014-02-27 12:45:24 PM

cherryl taggart: brimed03: parkke0108: Termites.

/That is all

Have to be termites with pretty damn strong teeth, or whatever they use.

/wood-dissolving acids?  Frickin' laser beams?

Formosan termites will find this to be a tasty treat, since those suckers devour railroad crossties soaked with creosote, and pressure treated lumber is not safe from them either.


From what I understand, borate treatment is pretty effective against Formosan termites. Maybe they could pretreat the wood before it gets formed/glued.
 
2014-02-27 12:49:31 PM

Honest Geologist: insulated concrete form buildings


Wow.  I had to look that up.  Yes, Boogar-- sorry, Buggar-- I GIS'ed it.  They look like igloo-cooler* material.  How solid/dense are they?


* A brand of styrofoam ice chest-- cheap, portable, disposable
 
2014-02-27 12:49:57 PM
There have been multi-story buildings made of chipboard going up all around where I live.  The first tornado that comes along should be interesting.
 
2014-02-27 12:51:29 PM
DO NOT WANT -- I've had enough battles with termites over the years.  Both subterranean and drywood.  It's only steel/glass/concrete for me.

Borate works on subterranean but not drywood.
 
2014-02-27 12:51:52 PM
If any of the engineering types in this thread are using Revit you should send me an e-mail.  My firm is looking for additional consultants
 
2014-02-27 12:51:57 PM

thecpt: Sorry to give you that hard time. I just know how the three building depts that I frequent would react to this design and all three are extremely different in their setup and what they normally see. In order to get this kind of design though, you'd need hundreds of hours allocated for an expeditor and for the design team to explain. The money needed (even after the supposed "savings") still isn't cheaper.

Maybe after 20 years of LEED trail blazers it would be cost efficient. I'm ...


No, no worries there.  Mind if I ask what you do?  Sounds like this is more your area of expertise and experience anyhow.
 
2014-02-27 12:53:28 PM
inner ted:the point is that wood is getting a bad rap on this thread.  nothing is indestructible.  wood has been used widely & forever cause it works well & it will continue to work well.  building with wood is a great way to store carbon (unless that building burns down), it regrows relatively quickly & is less toxic than many synthetic alternatives. of course it won't be nor should it be used for everything, but seeing new uses for something that has been used for a long time is a neat thing.

Hear hear.

/and there there.  Everywhere, really.
 
2014-02-27 12:55:57 PM
Buggar:  Hey, I'm not the one having trouble finding something.

That's not what the man in the boat told me.

I'm not going to do the GIS search for you cause that won't help you when you're on your own.

Which brings us to the main point: if you're not going to help, why not STFU?

And why aren't you feeding fark's squirrels?

So buy me some TF, you farker.
 
2014-02-27 01:01:20 PM

TheShavingofOccam123: inner ted: TheShavingofOccam123: inner ted: cgraves67: pheelix: cgraves67: Fun Fact: Tokyo was once built of wood. I wonder what happened to it?
[upload.wikimedia.org image 250x233]

No need to go further than Chicago to make your point.

I could also go with London 1666, but I thought a picture of an actual city burning would be more visceral.

cause we all know that steel & concrete building are impervious
[img.fark.net image 260x194]
/visceral enough?

We also know drywall doesn't make stairways survivable in extreme conditions. Which ends up dooming thousands of people to either burning to death or jumping.

That engineer sure saved a lot of money by using drywall instead of reinforced doodads. And it made his twin penises grow ever larger.

the point is that wood is getting a bad rap on this thread.  nothing is indestructible.  wood has been used widely & forever cause it works well & it will continue to work well.  building with wood is a great way to store carbon (unless that building burns down), it regrows relatively quickly & is less toxic than many synthetic alternatives. of course it won't be nor should it be used for everything, but seeing new uses for something that has been used for a long time is a neat thing.

definitely a neat thing. you can't grow concrete. and I'm all for using alternatives that you can grow.

like someone said above, a major concern--especially if the manufacturer has no problem cheating--is the adhesives used in these materials. if the maker cheats, there better be a thorough inspection system to catch it before it ends up in buildings (chinese drywall comes to mind). also, what about outgassing.

like I said though this is an interesting alternative to carving out huge expanses of the earth to get a hold of the raw materials for concrete and steel


quality of manufacturing & cutting corners must apply to things like steel & concrete & I'm sure there are plenty of inspectors to go around.  now.. if the inspectors are corrupted / bought off... well that goes beyond the scope of the product of course.

not sure about outgassing... but if it's similar to any other lam product, I'm sure it's just part of the production (i.e. once installed must be X days before can be sealed up or inhabited - totally guessing here, but it sounds good) but again, other products would have similar or worse environmental concerns.

don't get me wrong - the timber industry can leave it's mark, get way out of hand & over harvest etc.  but it is a highly regulated industry these days in n. america & most of europe & i'd challenge any other building product industry to be "greener" .

south america / africa / asia is a bit different story & I can understand why people biatch

/wood is good
/trees are the answer
 
2014-02-27 01:07:25 PM

croesius: cgraves67: Fun Fact: Tokyo was once built of wood. I wonder what happened to it?
[upload.wikimedia.org image 250x233]

[static.lolyard.com image 600x720]

Hint: It ain't wood.


Nagasaki is on the exact opposite side of Japan from the 2011 earthquake and tsunami, and was in no way impacted by it.
 
2014-02-27 01:12:07 PM

brimed03: stanadamsii: brimed03: Buggar: brimed03: Buggar: brimed03: The Irresponsible Captain: Interesting. Personally, I'm hoping that laminate beams will revive timber frame construction. The solid wood panels have some advantages that were missed. They insulate better than steel and wood, they flex more than concrete without breaking.

Without knowing what I'm looking for, all I could find for sure on Google was laminated beams.  Could you provide a relevant link?  I'm interested.

You poor thing, you can't find CLT?  Just do a GIS for CLT and you'll see a few diagrams and pictures that will help you more easily recognize it in the future.

The fun part is knowing that, before posting, you did exactly that just to make sure you didn't sound like some jerk idiot.

/didn't work

Well you were obviously searching for it in the wrong way.  Don't get mad at me cause you're looking in all the wrong places.

I had Google-searched "cross-laminated timber."  Forgive me for not being so bright as to think of using the less-specific abbreviation.

Try looking for cross laminated integrated timber....

See, Buggar?  Now this is some funny shiat.  So voted, too.


I see how it is, kick that man that provides you genuine advice, and reward the one that cracks a joke at your expense.
 
2014-02-27 01:14:32 PM

brimed03: parkke0108: Termites.

/That is all

Have to be termites with pretty damn strong teeth, or whatever they use.

/wood-dissolving acids?  Frickin' laser beams?


Don't forget ants, carpenter ants come with their own tools.
 
2014-02-27 01:15:18 PM

brimed03: Buggar:  Hey, I'm not the one having trouble finding something.

That's not what the man in the boat told me.

I'm not going to do the GIS search for you cause that won't help you when you're on your own.

Which brings us to the main point: if you're not going to help, why not STFU?

And why aren't you feeding fark's squirrels?

So buy me some TF, you farker.


I did help.  I showed you how to fish.  I don't do charity.
 
2014-02-27 01:15:26 PM
May as well ask here.

After having lived in concrete tower(s) for the last 8 years (and enjoying the relative quiet), I'm planning on purchasing/moving to one of two wood frame buildings - one built last year, one built in 2008.

The last wooden building I lived in (renting) was about 40 years old or so, it was pretty bad. Neighbours above and below could hear us, bits of the floor would seem to sag as we walked over them, or at least cause nearby upright furniture to sway.

How well have low-rise, wood construction materials and techniques advanced in that time span?

/Vancouver, BC

Thanks.
 
2014-02-27 01:22:12 PM

Nexzus: May as well ask here.

After having lived in concrete tower(s) for the last 8 years (and enjoying the relative quiet), I'm planning on purchasing/moving to one of two wood frame buildings - one built last year, one built in 2008.

The last wooden building I lived in (renting) was about 40 years old or so, it was pretty bad. Neighbours above and below could hear us, bits of the floor would seem to sag as we walked over them, or at least cause nearby upright furniture to sway.

How well have low-rise, wood construction materials and techniques advanced in that time span?

/Vancouver, BC

Thanks.


IME, the age has more to with it than wood frame vs concrete and steel due to sound transfer coefficients becoming more important. The sound transfer should be better in wooden buildings, but it depends more on the acoustical material and construction between floors.

Gypsum ceilings vs act
Isolated hangars?
Carpeted floors?

These things often matter more
 
2014-02-27 01:23:26 PM

brimed03: thecpt: Sorry to give you that hard time. I just know how the three building depts that I frequent would react to this design and all three are extremely different in their setup and what they normally see. In order to get this kind of design though, you'd need hundreds of hours allocated for an expeditor and for the design team to explain. The money needed (even after the supposed "savings") still isn't cheaper.

Maybe after 20 years of LEED trail blazers it would be cost efficient. I'm ...

No, no worries there.  Mind if I ask what you do?  Sounds like this is more your area of expertise and experience anyhow.


I am by no means an expert, but I do speak from the experience of working in a construction mgmt and design firm
 
2014-02-27 01:23:35 PM

Nexzus: May as well ask here.

After having lived in concrete tower(s) for the last 8 years (and enjoying the relative quiet), I'm planning on purchasing/moving to one of two wood frame buildings - one built last year, one built in 2008.

The last wooden building I lived in (renting) was about 40 years old or so, it was pretty bad. Neighbours above and below could hear us, bits of the floor would seem to sag as we walked over them, or at least cause nearby upright furniture to sway.

How well have low-rise, wood construction materials and techniques advanced in that time span?

/Vancouver, BC

Thanks.


If it helps at all, here's a Google Street View of the newer one during construction. Not sure what you could really glean from it, but here it is nonetheless.
Link
 
2014-02-27 01:35:49 PM

cherryl taggart: brimed03: parkke0108: Termites.

/That is all

Have to be termites with pretty damn strong teeth, or whatever they use.

/wood-dissolving acids?  Frickin' laser beams?

Formosan termites will find this to be a tasty treat, since those suckers devour railroad crossties soaked with creosote, and pressure treated lumber is not safe from them either.


I heard once abouy pressure treating lumber with water glass (sodium silicate). It's supposed to make the wood resistant to rot as well as nonflammable. Do you know if termites will eat such wood?
 
2014-02-27 01:37:41 PM

yet_another_wumpus: Mose: brimed03: Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.

I grant the guy's job is to shill for the industry.  But, bearing in mind that most of us don't know you, what credentials and expertise do you have over this guy?

BS mechanical engineering, MS fire protection engineering, 4 years as a full time firefighter, 8 years as a volunteer firefighter, 10 years professional fire protection engineering experience specializing in the performance of fire sprinklers.

Or, you might just happen to know that steel melts at ~2500F and that wood typically burns somewhere before that.  "Searing" is all well and good, but 2500F good?


At what temperature does it soften enough to no longer be capable of supporting the structural loads it is under though?  Because that's the kicker, not when it actually liquefies.

Whilst nothing can be made fireproof, wood and brick structures often remain structurally sound longer than steel framed ones for exactly the reason given in the article.  Design practice with timber (at least in the UK) requires slightly increasing the cross-sectional dimensions of structural timber joists so that the outside can char without the structural strength being reduced below that required to support the load.

Its been a while since i picked up a timber design guide (My degree is in Civil Engineering, which includes structures, but I ended up working in a different area of civils, then left to go into teaching) but IIRC it was something like 5mm of "cover" for every 30 minutes the structure was required to remain standing in event of fire.

I refer the reader to:


Structural fire engineering design: materials behaviour - timber
Julie Bregulla, Vahik Enjily & Tom Lennon
Sep 27, 2004


and

Guidelines for the construction of fire-resisting structural elements
W A Morris, R E H Read, G M E Cooke
Feb 1, 1988

Both published by the Building Research Establishment Ltd.
 
2014-02-27 01:42:27 PM

Nexzus: May as well ask here.

After having lived in concrete tower(s) for the last 8 years (and enjoying the relative quiet), I'm planning on purchasing/moving to one of two wood frame buildings - one built last year, one built in 2008.

The last wooden building I lived in (renting) was about 40 years old or so, it was pretty bad. Neighbours above and below could hear us, bits of the floor would seem to sag as we walked over them, or at least cause nearby upright furniture to sway.

How well have low-rise, wood construction materials and techniques advanced in that time span?

/Vancouver, BC

Thanks.


http://www.certainteed.com/resources/IG_Noisereducer-specifications- Ca nada-30-26-094.pdf

Nothing to do with the materials. Wood or metal framed, you still need insulation in the walls.  OLD building made of plaster, stone, mortar, etc. didn't need so much sound damping because the walls were essentially concrete.

Find out what kind of insulation they are putting in interior demising walls and floor/ceiling, and you'll have a decent idea if you will have the same problems.

To be clear, this is NOT the same as perimeter insulation against the climate.
 
2014-02-27 01:42:38 PM

GalFisk: cherryl taggart: brimed03: parkke0108: Termites.

/That is all

Have to be termites with pretty damn strong teeth, or whatever they use.

/wood-dissolving acids?  Frickin' laser beams?

Formosan termites will find this to be a tasty treat, since those suckers devour railroad crossties soaked with creosote, and pressure treated lumber is not safe from them either.

I heard once abouy pressure treating lumber with water glass (sodium silicate). It's supposed to make the wood resistant to rot as well as nonflammable. Do you know if termites will eat such wood?


That sounds like that would be fun to cut with a saw.
 
2014-02-27 01:44:42 PM

brimed03: Honest Geologist: insulated concrete form buildings

Wow.  I had to look that up.  Yes, Boogar-- sorry, Buggar-- I GIS'ed it.  They look like igloo-cooler* material.  How solid/dense are they?


* A brand of styrofoam ice chest-- cheap, portable, disposable


Yup, we've got Igloo coolers up in Canadaland, in addition to the actual igloos... ICFs are slightly more dense/stiff than that, but pretty much the same stuff.

Got into a conversation with a stonemason at a bar once... apparently since ICFs are stacked/assembled like masonry before they're filled with concrete, it's the masonry union instead of the concrete/formworker's union that gets all the ICF work.
 
2014-02-27 01:57:09 PM
Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.

brimed03: I grant the guy's job is to shill for the industry.  But, bearing in mind that most of us don't know you, what credentials and expertise do you have over this guy?


Wrong question - appeal to expert logical fallacy. Right question is, "What evidence - in the form of citations to reliable websites - do you have to back your assertion?"

1) Wood exposed to flame will burn at 250C : http://www.newton.dep.anl.gov/askasci/env99/env99397.htm

2) Steel loadbearing strength remains at 100% until 316C. At 593C it retains 50% strength: http://www.usfa.fema.gov/downloads/pdf/coffee-break/cb_fp_2012_50.pdf

Not a fire protection engineer but it seems to me that the grate which holds the firewood doesn't burn, but the firewood in the grate does.
 
2014-02-27 02:06:05 PM

SmellsLikePoo: http://www.certainteed.com/resources/IG_Noisereducer-specifications- Ca nada-30-26-094.pdfNothing to do with the materials. Wood or metal framed, you still need insulation in the walls. OLD building made of plaster, stone, mortar, etc. didn't need so much sound damping because the walls were essentially concrete.Find out what kind of insulation they are putting in interior demising walls and floor/ceiling, and you'll have a decent idea if you will have the same problems.To be clear, this is NOT the same as perimeter insulation against the climate.


Ah Thank you. I'm looking for the relevant code regarding demising walls in this region, but are you able to tell what the generally accepted practice is? Is the use of a material like that batting you linked to common?
 
2014-02-27 02:06:34 PM

Buggar: GalFisk: cherryl taggart: brimed03: parkke0108: Termites.

/That is all

Have to be termites with pretty damn strong teeth, or whatever they use.

/wood-dissolving acids?  Frickin' laser beams?

Formosan termites will find this to be a tasty treat, since those suckers devour railroad crossties soaked with creosote, and pressure treated lumber is not safe from them either.

I heard once abouy pressure treating lumber with water glass (sodium silicate). It's supposed to make the wood resistant to rot as well as nonflammable. Do you know if termites will eat such wood?

That sounds like that would be fun to cut with a saw.


Interesting:

Cutting TimberSIL® GlassWood®
Sawing or cutting TimberSIL® is very similar to normal wood, but it is denser. Your saw cut will
take slightly longer. Think of cutting hardwood - it is denser so the saw has to work harder to
get through it. The glass surrounding the fiber is microscopic flakes and is not harmful like the
fibrous silica in cementious boards. It is recommended that the same breathing protection and
eye protection you would wear with any wood cutting job be used with TimberSIL® GlassWood®.
The woodcut waste and sawdust is completely safe and can be ground up for mulch or put in
the trash. No special precautions are necessary for landfill acceptance as this product is
completely non-toxic. TimberSIL® GlassWood® is safe for ground contact (non-cut ends
only).
Boards that are ripped are not warranted. If cut ends are placed in the ground we
require the use of an end sealer such as an epoxy-based, Anchor Seal product to protect the
cut surface in the ground.

No where in their literature do they mention termites specifically except to say-
There is enough glass added throughout the board to produce significant advantages in durability, strength, hardness,
stiffness, and resistance to insects and fire.
 
2014-02-27 02:07:58 PM

Buggar: CLT is real. Once you learn how to use it properly a whole new world opens up.  But you can't just grab it and go banging and nailing willy nilly.  You gotta plan, evaluate the terrain, inspect the ground up close and build a proper foundation before you go laying the CLT down.


You, sir, are amazing.
 
2014-02-27 02:10:05 PM
Also... wood acts as fuel for a fire while steel does not.
 
2014-02-27 02:11:19 PM

Mose: brimed03: Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.

I grant the guy's job is to shill for the industry.  But, bearing in mind that most of us don't know you, what credentials and expertise do you have over this guy?

BS mechanical engineering, MS fire protection engineering, 4 years as a full time firefighter, 8 years as a volunteer firefighter, 10 years professional fire protection engineering experience specializing in the performance of fire sprinklers.


Well, ok then.
 
2014-02-27 02:27:12 PM

Nexzus: Ah Thank you. I'm looking for the relevant code regarding demising walls in this region, but are you able to tell what the generally accepted practice is? Is the use of a material like that batting you linked to common?


It is certainly a good practice, especially for residential, but not something necessarily code enforced.  More a build quality issue.  If it is still under construction and you are negotiating a purchase, you can easily ask for a minimum R-value of 8 or 12.  The thickness of the partitions will limit this, but 12 is generally doable.

Batt insulation is the standard for these types of applications, but if you are retrofitting (they've already hung the drywall) you can use blown insulation.  They cut small holes and pump the walls full of insulation. Depending on your framing, this can be a real pain.  It isn't as effective and it costs more, but it will help.
 
2014-02-27 02:36:16 PM

notatrollorami: Buggar: CLT is real. Once you learn how to use it properly a whole new world opens up.  But you can't just grab it and go banging and nailing willy nilly.  You gotta plan, evaluate the terrain, inspect the ground up close and build a proper foundation before you go laying the CLT down.

You, sir, are amazing.


Thanks but I must give most of the credit to the cold medication I'm on right now.
 
2014-02-27 02:52:07 PM

Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid  venal self-interest in those sentences right there, I don't know where to begin.

 
2014-02-27 03:22:29 PM

brimed03: BigGrnEggGriller: I'm a real-life structural engineer, and wood "towers" would be stupid.  Wood is...

Now this is an interesting and informed criticism.  Not being snarky, I am referring to parts of the comment I snipped out for brevity.

his means deeper floors and fatter columns, which increases floor-to-floor heights and lessens floor sq footage.  All this decreases economy.

And also, I'd intuit (in my uninformed way), leads to more of the "creep" you mention below.  Which requires more cladding.  Which requires more structural support (deeper floors/fatter columns).  Which increases weight and leads to more creep. Which requires...


Let's say we're designing a floor beam.  If it's steel, we can determine its deflection under load and decide if it's within acceptable limits.  It's finished deflecting after the load is applied, and it won't deflect any more.

If it's wood, we can determine its immediate deflection under load, but will need to multiply this value by a factor (or series of factors) depending on the type of wood and type of load to get the final value.  This is because the wood beam will continue to deflect over time, or "creep" so to speak.  If you've seen old houses with long-span covered patios, you can see the patio cover sagging in the middle due to this creep.  It was probably pretty level when it was built

For buildings up to about 3 or 4 stories, the vertical shortening of buildings due to this creep is within tolerances; you can work around it.  But if you're talking a 30 story building, you'd have to account for this shortening somehow.  And accounting for things like this costs money.


Plus, I'd be a little skeptical about how much this baby's going to sway.  It's basically relying on plywood to keep it rigid.

Hadn't thought about that.  At what height do tall buildings need to start factoring in wind sway?


It's not so much the height, as it is the aspect ratio, which is the height/base width.  If it's tall and spindly, you're going to get into wind resonance territory, and the stiffer a building is, the better.  As I mentioned before, wood is "springier" than steel, so if you have two identical structures, one of wood and one of steel, the steel one will be stiffer just due to basic material properties.

Then you have the connection issues.With steel, we can use welds or fully-tensioned high strength bolts (which literally squish the two connected members together so tight that they won't move).  With wood, you've got nails or fat bolts which easily overpower the wood their connecting, so you'll end up with a gazillion bolts at the ends of braces or whatever trying to transfer relatively high forces into a relatively weak material
.

Bottom line is, you'd have to do a bunch of special stuff to get this to work, and "special stuff" is expensive.

On a side note, the design of tall buildings is quite an interesting field.  If you can picture being a giant, and pulling the top of a tall building back, and then letting it go, it will vibrate at a certain frequency, which is it's "natural frequency".  If the natural frequency of a building matches, or is close to, the frequency of the wind or seismic driving force, you can get resonance, and then you've got a wiggly building.
Now if you take a big heavy weight and put it in the middle of your building, then pull it back again and let go, it will vibrate differently than it did without the weight
You've modified its natural frequency.  Modify it enough, and you get away from the resonance problem.  This is done all the time in steel/concrete buildings.  They can handle the several hundred ton weight that's required.  I'd hate to try it with wood.

Also, how is this baby gonna do in an earthquake?  Can you use those earthquake cables/anchors/springs/whatever they are, on these?

The seismic load on a building is proportional to its weight.  So a heavy precast parking garage is going to generate higher seismic loads than a wood building of similar size.  Interestingly, a well-connected wood building would be a good place to ride out an earthquake. A wood building 30 stories high, or so, may do just fine in an earthquake.

The key in seismic design is to connect things together.  The roof needs to be connected to the walls, the walls to the floors
, etc.  We call it load path, but it needs to be continuous, and strong enough.And all masonry needs to be reinforced with steel rebar.
The reason you see all those collapsed buildings in 3rd world countries after earthquakes is because they use easily-obtained bricks (of whatever material), stack them up, and run floors across.  They don't reinforce the walls or tie the floors (or roof) to the walls. Shiat starts shaking, the walls crumble, the roof and floors slip off any remaining walls, and people get squished.


 If steel is designed tight, this can lead to big deflections, and other issues.

I've no idea what any of this means, but I'd like to.  Would you explain?


Sure.  In a typical case, we design steel beams to (safely) use up their capacity.  Using a bigger beam than is required is wasting material.  Counter to what the renowned metallurgist Rosie O'Donnell propounds, heating up steel effectively weakens it, both in its strength and it's elasticity.So a hot beam will deflect more, and be weaker than, a cool beam.  At the same time, the hot beam is expanding along its length, pushing on the column or girder that's supporting it.  Lots of things going on to alter the layout of the steel as compared to its original layout.

This is why we use fireproofing on steel.  It's either wrapped in drywall (which is made up of gympsum) or sprayed with a fibrous insulating mixture.  We want to avoid these unpleasant things from happening.

On 9/11, one of the contributing factors for the failure of the towers was that the fireproofing of the floor joists was knocked off.  The fires heated the steel joists, and they sagged under the weight of the floors.  Eventually they broke away from the wall.  So now you've got the wall columns spanning much farther than they did before.  Think of a wood yardstick.  If you set it on its end and push on it, it will buckle outward at a certain "load" that you apply with your hand.  Now have someone "brace" the stick 1/2 way up and push on it.  It takes much more force to make it buckle.  In the towers, the floors acted like your friend holding the yardstick, bracing the column.  When the floor failed (your friend lets go), the exterior wall lost a lot of its capacity.  The weight of the floors above were more than it could handle, and it buckled, just like your yardstick.

Anyway, it's kind of a slow Thursday, so I prattled on a bit.  Hope I answered some of your questions
 
2014-02-27 03:49:27 PM

max_pooper: brimed03: Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.

I grant the guy's job is to shill for the industry.  But, bearing in mind that most of us don't know you, what credentials and expertise do you have over this guy?


Let's see, who should I listen to, a registered Professional Engineer with PhD from Berkley or a farker with a GED in buildingology?


I'm a registered professional engineer with (only) a Master's from Berkeley.  Here's the deal:

At the temperature of a normal fire, unprotected steel might lose half of its strength.  If the building isn't heavily loaded that might be good enough to keep it standing.  Steel is always fireproofed, usually with spray-on stuff that is supposed to keep the steel from getting any hotter than that.  I don't know a whole lot about fireproofing, we leave fire protection to the fire protection experts (or the architect, who then leaves it to the fire protection experts).  Now, in a hydrocarbon fire like what the WTC experienced, the temperatures are high enough that steel loses about 90% of its strength - that's spaghetti.  It doesn't melt, though.

Wood members that are thick enough do pretty well in fires.  I don't know how well, I mostly work with steel and concrete.  When it comes to greenhouse gases, concrete is easily the worst.  I don't care how much architects claim they can use its thermal mass to reduce the need for HVAC systems, they aren't good at getting it right yet, and in high seismic zones you need so much rebar that the rebar alone matches the amount of steel a steel building would use.  The cement in concrete is responsible for 8-9% of our total CO2 emissions.

Timber can definitely go higher than the 3-4 stories we're used to right now, but it'll be a long adjustment period because it's a whole new set of reference documents and construction procedures that everybody has to learn.  My guess is, in the beginning these buildings will combine steel and timber.
 
2014-02-27 04:19:54 PM

carlisimo: max_pooper: brimed03: Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.

I grant the guy's job is to shill for the industry.  But, bearing in mind that most of us don't know you, what credentials and expertise do you have over this guy?


Let's see, who should I listen to, a registered Professional Engineer with PhD from Berkley or a farker with a GED in buildingology?

I'm a registered professional engineer with (only) a Master's from Berkeley.  Here's the deal:

At the temperature of a normal fire, unprotected steel might lose half of its strength.  If the building isn't heavily loaded that might be good enough to keep it standing.  Steel is always fireproofed, usually with spray-on stuff that is supposed to keep the steel from getting any hotter than that.  I don't know a whole lot about fireproofing, we leave fire protection to the fire protection experts (or the architect, who then leaves it to the fire protection experts).  Now, in a hydrocarbon fire like what the WTC experienced, the temperatures are high enough that steel loses about 90% of its strength - that's spaghetti.  It doesn't melt, though.

Wood members that are thick enough do pretty well in fires.  I don't know how well, I mostly work with steel and concrete.  When it comes to greenhouse gases, concrete is easily the worst.  I don't care how much architects claim they can use its thermal mass to reduce the need for HVAC systems, they aren't good at getting it right yet, and in high seismic zones you need so much rebar that the rebar alone matches the amount of steel a steel building would use.  The cement in concrete is responsible for 8-9% of our total CO2 emissions.

Timber can definitely go higher t ...



The hydrocarbon fire in the WTC's didn't last long after the fuel exploded. The office fires weren't hot enough to reduce the temper in the steel.
 
2014-02-27 05:04:20 PM

SmellsLikePoo: codenamewizard: The walls built just get harder and harder over the years while pure concrete degrades after about 40 years and begins to crumble.

Here are some examples of things that cause concrete to degrade:

http://en.wikipedia.org/wiki/Concrete_degradation

Time, however, is not one of them.  Concrete is a material that gains strength...pretty much forever.  It is an asymptotic curve, but none-the-less it should make gains forever.  Just look at the Roman aquaducts.


---------

Okie....I believe you, sounds good.  I have no real knowledge of the subject other than what I read.  I was just impressed with the hempcrete and all the cool things they said about it and thought I would share. In the US we are kind of missing out on a plant material that has what seems like thousands of practical uses and is easily grown.  We avoid it because of it's link to cannabis....even though the THC level in this type of hemp is too low to cultivate for drug use.  This could be a Trillion dollar industry, especially in a nation with a large agricultural base.
 
2014-02-27 05:07:36 PM

Deep Contact: carlisimo: max_pooper: brimed03: Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.

I grant the guy's job is to shill for the industry.  But, bearing in mind that most of us don't know you, what credentials and expertise do you have over this guy?


Let's see, who should I listen to, a registered Professional Engineer with PhD from Berkley or a farker with a GED in buildingology?

I'm a registered professional engineer with (only) a Master's from Berkeley.  Here's the deal:

At the temperature of a normal fire, unprotected steel might lose half of its strength.  If the building isn't heavily loaded that might be good enough to keep it standing.  Steel is always fireproofed, usually with spray-on stuff that is supposed to keep the steel from getting any hotter than that.  I don't know a whole lot about fireproofing, we leave fire protection to the fire protection experts (or the architect, who then leaves it to the fire protection experts).  Now, in a hydrocarbon fire like what the WTC experienced, the temperatures are high enough that steel loses about 90% of its strength - that's spaghetti.  It doesn't melt, though.

Wood members that are thick enough do pretty well in fires.  I don't know how well, I mostly work with steel and concrete.  When it comes to greenhouse gases, concrete is easily the worst.  I don't care how much architects claim they can use its thermal mass to reduce the need for HVAC systems, they aren't good at getting it right yet, and in high seismic zones you need so much rebar that the rebar alone matches the amount of steel a steel building would use.  The cement in concrete is responsible for 8-9% of our total CO2 emissions.

Timber can definitely ...


Wow show us your thermal imaging camera video that you took when you walked through the towers while they were on fire.
 
2014-02-27 09:41:22 PM

Crewmannumber6: rumpelstiltskin: Has the internet sunk so low that blog writers feel free to write "circumambulates"?

Circumambulates is the name of my They Might Be Giants cover band


Can you make a little birdhouse in your soul with CLT?
 
2014-02-27 09:51:26 PM

Buggar: Deep Contact: carlisimo: max_pooper: brimed03: Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.

I grant the guy's job is to shill for the industry.  But, bearing in mind that most of us don't know you, what credentials and expertise do you have over this guy?


Let's see, who should I listen to, a registered Professional Engineer with PhD from Berkley or a farker with a GED in buildingology?

I'm a registered professional engineer with (only) a Master's from Berkeley.  Here's the deal:

At the temperature of a normal fire, unprotected steel might lose half of its strength.  If the building isn't heavily loaded that might be good enough to keep it standing.  Steel is always fireproofed, usually with spray-on stuff that is supposed to keep the steel from getting any hotter than that.  I don't know a whole lot about fireproofing, we leave fire protection to the fire protection experts (or the architect, who then leaves it to the fire protection experts).  Now, in a hydrocarbon fire like what the WTC experienced, the temperatures are high enough that steel loses about 90% of its strength - that's spaghetti.  It doesn't melt, though.

Wood members that are thick enough do pretty well in fires.  I don't know how well, I mostly work with steel and concrete.  When it comes to greenhouse gases, concrete is easily the worst.  I don't care how much architects claim they can use its thermal mass to reduce the need for HVAC systems, they aren't good at getting it right yet, and in high seismic zones you need so much rebar that the rebar alone matches the amount of steel a steel building would use.  The cement in concrete is responsible for 8-9% of our total CO2 emissions.

Timber c ...


Woman standing where plane entered shows temperature of fires are inconsequential to affect steel.
www.thevoiceofreason.com
 
2014-02-27 09:52:32 PM

Mose: A thick plank of wood will char on the outside, sealing the wood inside from damage. Metal, on the other hand, begins to melt. "Steel, when it burns, it's like spaghetti," says B.J. Yeh, the technical services director for APA-the Engineered Wood Association.

There's so much stupid in those sentences right there, I don't know where to begin.


Well, he's kind of right. Steel will melt, and even burn if you heat it enough. Wood will char as long as you don't heat it too much.

/ hardwood framed house
// timber clad
/// timber internal panelling
//// timber floors
// slate bathroom
 
2014-02-27 10:31:21 PM

Maud Dib: [www.popsci.com image 311x716]

[ad009cdnb.archdaily.net image 528x383]


What about the rotating knives?
 
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