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30 story wood high rise building

It could be done with CLT but it would not be classified as a Type I A construction. It would have to be done under the ICC Performance Code for Buildings and Facilities. It would not be possible under the current IBC

[h=2]Cross Laminated Timber (CLT) Benefits[/h][h=3]Strength[/h]

  • Allows wood to be used in never before seen buildings like 30 storey high rises
  • Cross lamination creates perfectly uniform strength properties like steel and concrete
  • Creates new possibilities in cantilevers and load bearing
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Due to its amazing strength properties, CLT can be utilized in applications such as high-rises that wood has previously never been adequate for. The high strength properties have more benefits than just being able to build higher and make longer spans, they are evident in all the other amazing advantages CLT has. Any weakness in the individual stick of lumber is cancelled out by the cross lamination with other pieces until there is a single timber panel with uniform strength properties closer to reinforced concrete than wood. Lastly, cantilevers and loads can be designed in any direction rather than just one, offering exciting new design possibilities.

[h=3]Fire[/h]

  • Low surface area doesn’t sustain a flame so fires burn themselves out
  • Airtight construction lowers the fires’ oxygen supply, gas does not travel through the panel
  • Heat does not conduct from side of the panel to the other
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The fire performance of CLT is better than any other wood building system. The low surface area and the airtight environment compared to standard wood construction also helps to inhibit fire growth in a contained space by limiting the available fuel. Even a normal installed panel does not allow fire to burn through which encapsulates the flame in a single area, suffocating it. Another great attribute is the solid thermal mass. This allows one side of the panel to be close to 1000 degrees Celsius while the other side is room temperature.

[h=3]Seismic[/h]

  • Combination of strength, ductility and light weight form the ideal earthquake-proof system
  • Shake table tests up to 7 storeys prove that CLT buildings have excellent performance
  • No loss of life or structural damage even against the strongest earthquakes
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CLT is immensely strong, ductile, and light; the perfect attributes for an earthquake-proof building system. Seismic tests prove that CLT buildings can handle the world’s strongest earthquakes with no loss of life or structural damage. The high strength-to-weight properties decrease the seismic forces acting against the structure, making these buildings extremely safe while simultaneously allowing for smaller foundations. A 7 storey CLT building was shaken by the world’s largest shake table in Japan by 10 earthquakes and survived perfectly intact. CLT floor spans in a theoretical 24 storey high-rise have shown to reduce seismic load by 50% compared to reinforced concrete.

[h=3]Acoustic and Vibration[/h]

  • Solid wood panels give excellent acoustic insulation
  • Vibration design can satisfy the strictest building codes
  • Construction process is nearly soundless, perfect for urban projects
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When replacing stick-frame walls, solid timber gives a massive upgrade in acoustic performance. CLT construction gives the home an airtight enclosure of solid mass elements, and with the proper design can satisfy the strictest acoustic ratings even in multi-storey residential buildings.

[h=3]Thermal Insulation[/h]

  • Ideal building system for Passive Homes - that don’t require heating systems
  • Can trap 90% of the heated air that escapes from normal homes
  • High thermal mass of timber keeps home warm in the winter and cool in the summer
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CLT is perfectly suited for passivhaus designs that are so efficient at insulating a home they don’t need any heating systems. The airtight environment doesn’t allow heat to leave through cracks, while the average home has cracks that add up to the size of a basketball. The high thermal mass of the timber also helps keep the interior temperature stable throughout the day – warm in the day, cool at night.

[h=3]Durability[/h]

  • Has the best long-term stability of any wood building system
  • CLT eliminates swelling , shrinkage, warp, and creep – main barriers to normal wood construction
  • The stability allows for precision building and new higher wood towers
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Due to the cross laminated engineering, CLT has much better durability characteristics than solid wood. Long-term movement by the wood itself due to swelling, shrinkage, warp, and creep has been minimized to insignificant levels even for the tallest applications, opening up new frontiers for wood construction. Our product is tested constantly to ensure long-term lamination quality.

[h=3]Installation Efficiency[/h]

  • Manufacturing process minimizes on-site labour with off-site efficiency automation
  • Panel connections are based on simplified self-tapping screws
  • Can build a 9 storey building in 9 weeks instead of 27, even with a 4 person crew
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CLT adds tremendous value to underutilized lumber components by assembling them into precisely-machined building components. The assembly line method of manufacture maximizes efficiency off-site and minimizes the steps necessary to build a structure. We minimize the amount of transportation and manipulation necessary to extract maximum efficiency from the construction process. We simplify the assembly by lowering each panel and screwing it in place with just a few labourers in just 20 minutes. Erecting the shell of an entire house can take as little as 8 hours! Not only is it much safer to do, but it eliminates the waste from fine-tuning, squaring, cutting, and garbage disposal. All this amounts to the major benefits of completing the project in a fraction of the time it would normally take, making it more profitable, easier to estimate, and less risky for the workers, developers, owners, and investors.
 
RickAstoria said:
You do an inspection prior to any encapsulation, an inspection at partial encapsulation and after complete inspection as every floor is built before the next floor is built. It isn't rocket science.
texasbo said:
Rick, you might be on to something here. Consider the following: What if you built this 30 story tall building out of wood, then as you have suggested, you encapsulate the wood with cinder blocks, concrete, steel, refractory brick, space shuttle tiles, etc ? Build it such that it will give you a rated, and noncombustible structural frame, surrounding the wood. Then, you very carefully slide the wood out of the assembly, right before inspection. That might let you have your cake and eat it too, no?
Hey! if you recycled the wood from floor to floor you'd probably earn some additional LEEDs credits.
 
Exactly. Slide the wood out from the first floor noncombustible/fire rated structure cocoon, and move it up to the next floor. Kind of like slip forming. And kind of not.
 
I think we all know it is not allowable under current codes, up for debate might be wether it could be allowable some day and what precautions would need to be taken with engineered wood products that now could physically be used to support a high rise wood framed structure...
 
steveray said:
I think we all know it is not allowable under current codes, up for debate might be wether it could be allowable some day and what precautions would need to be taken with engineered wood products that now could physically be used to support a high rise wood framed structure...
Read 703.3 and 703.4. Take not of 703.3 - Item #5.Then look at 104.11. Now, with that in mind, unprotected steel has no fire-resistance rating of any appreciable level under prescriptive methods. If you look at the Prescriptive table of Section 720 regarding Steel. The rating is entirely on the protection. The Steel is treated as having zip for fire protection. So a similar rating can be achieved very easily using the same methods.The attached pic is a concept for a fire-protected wood column. Do note that I did not specify the particular protective shell. They can be CMUs, bricks, multiple layers of Type X Gypsum wall board. The mechanism for adhering them to the wood structure should be similar to any mechanism normally required to adhere the type of protection chosen to the wood like brick veneer over wood studs or columns or whatever else provided the isolation buffer is maintained. 2" is based on the code requirements for wood separation from Chimneys. So the idea would be maintained. The adhering mechanism should be of material commonly allowed in the 2" space between wood studs and chimneys.View attachment 473

View attachment 473

/monthly_2011_08/572953c13359d_Fire-protectedwoodcolumnsectioncut.jpg.1f851f9511dfac59c14de3b16960cf0a.jpg
 
Steveray,

There is ways to do this but we would certainly want to test the assembly. I do believe it is well doable and using an assembly like that already used to protect steel with 3 to 4 hour fire-resistance rating just in the protective "shell" before the steel becomes exposed to excessive heat. Similar systems would protect wood the same way as it does steel. We can amend the code text in the future to allow fire-resistance rated protective shell over wood structural components.

Prescriptive assemblies rates only the shell or coating on steel structure. The core steel member is not part of the fire-resistance rating - only the protective shell or coating.

In my opinion, Type I & II construction requiring non-combustible material (and assemblies) is about fire-resistance rating. In the past, it was not that wood could not be used. It was that you needed things like CMU / Brick or 4-6" of poured concrete shell just to protect the wood with 3-hours rating that it was not systematically practical in economic terms. At a point, you would be better of just using reinforced concrete. Now it is possible to use Type-X drywall in multiple layers to get 3-hr rating and drywall alone would not make for a load-bearing structural material but wood, steel, concrete would make for a load-bearing structural material. In past, we have not engineered wood or hewn wood products that would bear the load that could be encountered in high-rise construction.

In past 50-60 years, we do have members that are stout and strong enough in terms of glulam. However, we need column connections to achieve the goal and certainly other engineering factors to be considered for lateral and moment resistance for both seismic and wind. Sway control would be necessary in the world of high-rise construction with many neighboring buildings.

I think we still need to achieve the spirit of Type I & II by protective covering of the wood. If it means, we need to add 1 additional hour to the required rating in Table 601 for a particular building element to light non-fire resistant coated wood stud members (vs. Fire-resistant coated Heavy Timber / GluLam wood )

Example: 4-hours rated protective shell for non-fire resistant rated wood stud walls. 3-hrs. - if the studs already has a fire-resistant coating. 4-hours rated shell for a non-fire-rated glu-lam. 3-hours shell if the Glu-Lam column has a fire-resistant coating.

A number of strategies can be achieved.
 
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How do you get around

TABLE 503 requires all buildings over 11 stories to be Type I A

602.2 Types I and II.

Types I and II construction are those types of construction in which the building elements listed in Table 601 are of noncombustible materials,

It just can't be done under todays IBC no matter how much protection you put around combustible materials they are still combustible under the code

The protecion around steel is to limit the steel from reaching 1,200 degrees F where it starts to loose its structural strength and a catastaphic failure can occur. Wood starts to ignite around 572 degrees F so additional testing would have to be performed.
 
mtlogcabin said:
How do you get around TABLE 503 requires all buildings over 11 stories to be Type I A

602.2 Types I and II.

Types I and II construction are those types of construction in which the building elements listed in Table 601 are of noncombustible materials,

It just can't be done under todays IBC no matter how much protection you put around combustible materials they are still combustible under the code

The protecion around steel is to limit the steel from reaching 1,200 degrees F where it starts to loose its structural strength and a catastaphic failure can occur. Wood starts to ignite around 572 degrees F so additional testing would have to be performed.
What defines the material as "noncombustible" in code. If the material is injected and coated with 6" of gypsum. The trick in the scenario is that the material of building element is outright noncombustible.

Steel will actually combust if gets hot enough and that is what it would take to get through 8-16 inches of solid Concrete (CMU). Flat out, it is IMPOSSIBLE for normal materials used in a building to get that hot and last that long to cause the wood to combust. If it got that hot, the steel is a pool of hot liquid metal.

Let's look at Non-combustible membrane for a second. Obviously the term is somewhat used to refer to a composite assembly of components. Obviously the membrane is of some material that obviously a composite of a core material that is combustible but due to the manufacturing process, it is coated with elements that makes it non-combustible to Section 703.4 or NFPA 701 flame propagation performance criteria. If the assembly of the building element halts propagation of flame spread right where it is at.

If we need to change the code, that is only a text amendment because NONE of the states have to adopt the building codes exactly according to ICC standards.

I already have considered how the text can be amended. Since a rated construction in Type I can assume that a building can instantly collapse in 3 hours + 1 nanosecond. Any point after the 3-hour mark (where 3-hours is required), the building is potentially at the point of collapsing at an undeterminable amount of time. Steel can collapse in matter of minutes or more depending on the alloy mixture. The prescriptive part in Section 720 (regarding steel) only assumes steel with the same fire-resistance rating as wood. Basically, none. The fire-resistance is in the protective component. Concrete and ceramic clay and brick and some similar materials are the only ones basically non-combustible.

Technically, steel does combust. Get some very fine steel wool and light it with a candle. Wood does that and by-product is carbon (ash). While steel does it differently. Steel has a melting temperature and an ignition temperature. The latter is a little higher than the melting temperature. Wood doesn't melt but has an ignition temperature. Large timbers will ignite to a certain point and then char. However, another factor to bear in mind is that with draftstops and fire blocks, there would lack the air necessary to sustain a fire. Therefore the assembly would be non-combustible.

I think it is all doable. We would want to have some testing and stuff and amend the code appropriately before wood is used in Type I & II construction.
 
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RickAstoria said:
Some pretty deep thoughts, then: "I think it is all doable. We would want to have some testing and stuff and amend the code appropriately before wood is used in Type I & II construction."
I just want to say that I think it's very sporting of you to require some testing and stuff before we allow wood structural elements in Type I and Type II high-rise construction.
 
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RickAstoria said:
What defines the material as "noncombustible" in code.
That would be 703.4, Rick. When you get a code book, you will discover that it has an index. Then you may discover that two hours typing will save you 45 seconds of code research.
 
What defines the material as "noncombustible" in code.
703.4 Noncombustibility tests.

The tests indicated in Sections 703.4.1 and 703.4.2 shall serve as criteria for acceptance of building materials as set forth in Sections 602.2, 602.3 and 602.4 in Type I, II, III and IV construction. The term "noncombustible" does not apply to the flame spread characteristics of interior finish or trim materials. A material shall not be classified as a noncombustible building construction material if it is subject to an increase in combustibility or flame spread beyond the limitations herein established through the effects of age, moisture or other atmospheric conditions.

703.4.1 Elementary materials.

Materials required to be noncombustible shall be tested in accordance with ASTM E 136.
 
mtlogcabin said:
703.4 Noncombustibility tests.The tests indicated in Sections 703.4.1 and 703.4.2 shall serve as criteria for acceptance of building materials as set forth in Sections 602.2, 602.3 and 602.4 in Type I, II, III and IV construction. The term "noncombustible" does not apply to the flame spread characteristics of interior finish or trim materials. A material shall not be classified as a noncombustible building construction material if it is subject to an increase in combustibility or flame spread beyond the limitations herein established through the effects of age, moisture or other atmospheric conditions.

703.4.1 Elementary materials.

Materials required to be noncombustible shall be tested in accordance with ASTM E 136.
Here is a simple amendment:

603.1 "Allowable Materials." Combustible materials shall be permitted in buildings of Type I or Type II construction in..... in accordance with Sections 603.1.1 through 603.1.3

1. Fire retardant-treated wood shall be permitted in:

1.1 ...

1.2 ...

1.3 ... Exception: ...

1.4 Any other building element, provided all exposed surfaces are protected by passive fire-resistant assemblies that meets the minimum fire-rating required for that building element as required for the Construction Type classification as denoted in Table 601 and elsewhere in this code as required or permitted. All such assemblies shall be tested or approved to meet the required fire-rating in accordance with Section 703.

This would basically address the allowance. This is simply a "draft" language. I think the idea is pretty straight-forward.

I would recommend testing assemblies prior to actual amendment of code.
 
texasbo said:
I just want to say that I think it's very sporting of you to require some testing and stuff before we allow wood structural elements in Type I and Type II high-rise construction.
That for one could also be something that if tested to provide the required level of protection and safety that it can be outlined prescriptively and if lucky, calculated method can be determined. Sizing the wood structural member and such would be something requiring engineering. I don't necessarily want to rule out wood for tall high-rises but we surely need to take prudent steps. Wood isn't a bad material for something like a 30 story high-rise. We need to consider proper connection ties just as you would with steel I-sections. We also need appropriate connectors and proper bracing. I would doubt the structure would be entirely out of wood. Even a wood frame house is hardly ever entirely made of wood in most cases.

I would expect stair wells (and the stairs themselves & landings) and possibly the elevator shafts to be of concrete / steel. It would allow for another material to be used in such. I wouldn't want someone to just erect a wood high-rise of 30 floors without there being some code guideline to ensure utmost safety.
 
RickAstoria said:
I would expect stair wells (and the stairs themselves & landings) and possibly the elevator shafts to be of concrete / steel. It would allow for another material to be used in such. I wouldn't want someone to just erect a wood high-rise of 30 floors without there being some code guideline to ensure utmost safety.
If the structural system of the 30 story highrise is wood, why would you not expect to see stairwell/stairs of wood?
 
texasbo said:
If the structural system of the 30 story highrise is wood, why would you not expect to see stairwell/stairs of wood?
That is a good point. The stairwell walls could very well use wood structural with the required fire-resistant rated protective shell.

The stair system itself might be a challenge to coat with 3-hour rated protective assembly and such. Perhaps that be possible too. I would probably

expect (for the time being) to have these stair system to be concrete as it would also help as a sort of mass-dampening. Like a spinal chord.

If one can come up with a 1" thick tread plate and kickplate of 3-hour fire rated it could very well work. From my understanding, stairways must be of 2 to 3-hour rated construction but I haven't noticed one way or the other what fire-resistance rating stairs themselves needs to be in Type I. I would almost treat them withe same rating as the floors for the stairs and landings while the vertical enclosure being treated Interior Bearing walls.

As I skim through the other sections, I see 2-hours for the enclosure but the stairs themselves...?

Currently, the economy of using concrete for the stairs themselves is currently the effective method to meet 3-hrs is still part of the challenge. I would be resistant to using Type-X Drywall in multiple layers for the stairs themselves to cover wood.
 
brudgers said:
That would be 703.4, Rick. When you get a code book, you will discover that it has an index. Then you may discover that two hours typing will save you 45 seconds of code research.
Ok. Good. What defined material.

I know it has an index. When words are not defined: Read 201.4.

When we are also talking about building materials and the dictionary definition is broad to apply to context that the definition isn't purely literal.

Material has a wide array of use and scope of meaning both in code but also in practice of use as ORDINARILY accepted and as context applies.

Therefore, we are talking about NON-COMBUSTIBLE (defined within code) building materials.

Are materials strictly limited to natural elementary elements OR does it include a composite assembly as a whole is to function accordingly.

Break down a non-combustible roof membrane into its own sub-parts, are all the sub-parts inflammable. The membrane in itself an assembly of parts.

Lets look at Composite Material. With any research, the topic is deep.

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

Now, an assembly of materials can very well become the building element. The assembly of materials are a composite. Therefore a composition. Say a layered composition of brick and wood. It need not be microscopic but can also be macroscopic.

When the definition is to be determine, the unit as a whole much function as a unit. An engineered solution, it may be. I would favor code amendment to minimize stretching the definition to the proverbial limit and simply make it clear and approved in approved assembly where it is protected by a fire-resistant protective shell.
 
RickAstoria said:
Ok. Good. What defined material. I know it has an index. When words are not defined: Read 201.4. When we are also talking about building materials and the dictionary definition is broad to apply to context that the definition isn't purely literal. Material has a wide array of use and scope of meaning both in code but also in practice of use as ORDINARILY accepted and as context applies. Therefore, we are talking about NON-COMBUSTIBLE (defined within code) building materials. Are materials strictly limited to natural elementary elements OR does it include a composite assembly as a whole is to function accordingly. Break down a non-combustible roof membrane into its own sub-parts, are all the sub-parts inflammable. The membrane in itself an assembly of parts. Lets look at Composite Material. With any research, the topic is deep. http://en.wikipedia.org/wiki/Composite_material Now, an assembly of materials can very well become the building element. The assembly of materials are a composite. Therefore a composition. Say a layered composition of brick and wood. It need not be microscopic but can also be macroscopic. When the definition is to be determine, the unit as a whole much function as a unit. An engineered solution, it may be. I would favor code amendment to minimize stretching the definition to the proverbial limit and simply make it clear and approved in approved assembly where it is protected by a fire-resistant protective shell.
Ricopedia is not a reference for the IBC.
 
brudgers said:
Ricopedia is not a reference for the IBC.
Then open your eyes and look around. Most materials in this world is a composite of materials. Very few things are purely their natural elementary material as found in nature.

This can be proven with facts that can be should with over 1 BILLION sheets of documentations including the patent documents as well.

I don't think a B.O. is going to refute that fact. Encyclopedias or Wikipedia is just convenient facts that is more in-depth than a dictionary definition which can be broad but not as in-depth as every documentation of something.

Lets take the question, WHY does Type I & II want non-combustible materials/assemblies used. What level of fire-resistance are they wanting for the material/assemblies before they expect potential failure. This would need a review of commentaries of the I-code and UBC when the requirements were initially enacted. Then review ICC interpretations.

Is it that they don't want building elements that is readibly combustible. Most fire-resistant coated lumber is only 1-hour rated coating. However, they want 3-hours so the issue then is what is wrong with using wood that is protected by a protective shell cladding that is at least 3-hours rated.

It isn't like it'll burn and collapse any faster than a steel frame building with same or similar cladding. Large glu-lam columns that are oversized for the load conditions will char over like heavy timber and then the charing will protect the wood from further combustion as long as the ash char coating stays on the wood - of course. That can be a helpful trait. Another factor to consider is, if the assembly is enclosed, the air would be limited. Therefore, fire would not be sustainable unless there is a continuous supply of oxygen. That would be something a proper assembly would not have unless a hole burns through the protective cladding to supply new air. However, you still have draft stops and fire blocks and that kind of stifles the fire propagation. There has to be a whole in the cladding for new supply of oxygen unless you have a magnesium fire. Which you would know your screwed because that is like Thermite which steel, concrete, and wood is not going to protect against. It will be consumed.
 
I hope I don't live long enough to see this perversion of construction types. Type III has already been perverted so as to be meaningless.
 
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