Posted on 03/21/2014 5:33:42 AM PDT by SJackson
Wood can be made fire retardant. The Twin Towers collapsed, they were made from steel and concrete. Steel melts and deforms when subjected to fire too.
LVL can replace steel when it comes to tensile strength. This gives you the rigidity and span. It is lighter than steel.
I do concede than connections could be a major issue. This why you see steel plate connectors inside timber framed structures. The specific gravity of lumber is too low to hold bolts without steel reinforcement.
What I can envision are multistory buildings that would be a combination of steel/LVL/concrete hybrid construction.
Each one of these materials has its advantages. The cost of materials will determine if at some point in the future they are economically feasible.
Now your pickin up what I’m puttin down. :)
Slang for: we understand each other.
First of all, I want to leave aside the issue of wood as primary structural members in highrise construction because that is all very special case issues with hundreds of angles involved.
In low rise and mid rise construction, the heavy timber and glue lam timber members do have some good features.
See:
http://www.aitc-glulam.org/ShopCart/Pdf/superior%20fire%20resistance.pdf
The thing that many people don’t realize is that in most fires, steel does not hold up to heat nearly as well as would be assumed for a non-combustable member — it conducts heat too well.
I have seen buildings burnt out where heavy timber survied and the steel members did not for this very reason.
What ever member is used for primary framing, fire resistance is more a factor of the fire protection, fire resistive elements, contents and fire suppression than the issue of primary structural members.
When I have looked at these matters before on fire code appeals boards, the issues are very complex and have to center around tested “assemblies” of materials used in a rated wall, roof, floor, or structural system and its surviability in “hours” as rated by an accredited testing lab. Simple material characteristics alone do not provide all the answers.
To the thread in general, our one poster from the wood and timber industry has tried to present some surprising insight and we have beat him up as though he is trying to excuse Obama. While there is a lot of ‘grant money’ thinking and waste in all of these programs, not every participant is malicious — either in the programs or someone offering comments on our forum.
Trees are a renewable resource, but wood is not suitable for high rise construction. Simple facts seem to escape this regime.
global warming is a hoax that democrats created to grow socialism(big government) and destroy capitalism(freedom)
As an engineer who oversees building design, I can confirm that wood composites CAN be pound-for-pound stronger than steel when considering building structures applications.
Fire spread is much less of an issue today due to extensive sprinkler and fire barrier requirements. Even steel is not fireproof and must be coated/enclosed. Wood can be covered in the same fashion to survive several hours of fire.
However, manufacturing such advanced composites in the quantity and size needed for a building would cost far more than steel and will most likely be less “green” overall.
Also, steel can be melted down and recycled easily. Such wood composites can’t and new trees must be cut each time.
IMO, this is another “green” gimmick to make someone money through government force.
Toche
But stone lasts longer FRiend:
http://www.bing.com/images/search?q=giza+pyramids&qpvt=giza+pyramids&FORM=IGRE
Well, in today’s society, there is a factor known as design life. While some buildings might be designed to last a very long time, most are not.
I cannot cite an example but am pretty sure there are Roman concrete structures presently in use
He never hard of the Chicago Fire I guess.
The Casa Nostra does a better job of laundering money.
;)
“Well it was late last night, when we were all in bed....”
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