France does not have big enough trees to replace Notre Dame's medieval beams
Wouldn't it be an honor if the US could donate trees [I have no idea if we have large enough trees} and be part of this historical rebuilding!!
France does not have big enough trees to replace Notre Dame's medieval beams
https://www.ctvnews.ca/world/france-does-not-have-big-enough-trees-to-replace-notre-dame-s-medieval-beams-1.4382570?utm_campaign=trueAnthem:+Trending+Content&utm_content=5cb718e20f1cfa0001e69d9d&utm_medium=trueAnthem&utm_source=twitter
Notre Dame Cathedral fire: before & after photos
The church was built in the heart of Paris over a period of nearly 200 years, between 1163 and 1345.
Cillian O'Brien, CTVNews.ca writer
Last Updated Tuesday, April 16, 2019 6:00PM EDT
A French cultural heritage expert says France no longer has trees big enough to replace ancient wooden beams that burned in the Notre Dame fire.
Bertrand de Feydeau, vice-president of preservation group Fondation du Patrimoine, told France Info radio that the wooden roof that went up in flames was built with beams more than 800 years ago from primal forests.
He says the cathedral’s roof cannot be rebuilt exactly as it was before the fire because “we don’t, at the moment, have trees on our territory of the size that were cut in the 13th century.”
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De Feydeau said the restoration work will have to use new technologies to rebuild the roof.
Meanwhile, David Elstone, executive director of B.C.-based Truck Loggers Association, said his province would not have suitable oak, but if architects required soft wood timber Canada could help.
“We probably have a tree that would suit the needs of the architects that are trying to rebuild Notre Dame,” he said.
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Only four per cent of Europe’s remaining woodland is primary forest, according to a study published last May, with none larger than 500 square kilometers outside of Russia or Northern Europe...................................
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By Will Macht
November 19, 2018
Until recently, buildings taller than five stories had to be constructed of steel or reinforced concrete, both of which require about 80 percent more energy to produce and represent about 200 percent more greenhouse gas emissions than cross-laminated timber (CLT), a new engineered wood product.
Portland developer Ben Kaiser of the Kaiser Group recently completed the tallest American CLT mass timber building—an eight-story, 16-unit condominium/retail tower on an 8,470-square-foot (787 sq m) lot. (Another tower rising in Portland will soon surpass that height.) Residents enter the building—designed with only two units per floor—directly from an elevator into their own units. Light and ventilation from three directions around the condo units give them more the feeling of a house than of an apartment. The combination of exposed CLT wooden ceilings and exposed glulam posts and beams on a 12-by-12-foot (3.7 sq m) and 12-by-15-foot (3.7 by 4.6 m) grid, along with oak floors, lends a warm wooden patina to the units offset by vertical white drywall panels between the windows around the unit and in the kitchens and the bathrooms.
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The Structure
Carbon 12 is designed, metaphorically, like a tree—a design that reduces the structural need for a concrete foundation and is akin to a sophisticated pole building. (Kaiser Group)
Carbon 12 is designed, metaphorically, like a tree. Its roots are a forest of steel piles driven 45 feet (14 m) deep into the ground to secure resistance to seismic pressures below and to wind loads above. The piles support a three-dimensional grid of glulam posts and beams onto which CLT panels measuring 37 by 11 feet (3 by 11 m) are lifted and locked into place. Plywood splines bind these panels to form an exceptionally solid diaphragm. Structurlam Mass Timber Corporation, based in Penticton, British Columbia, Canada, prefabricated the large CLT panels and glulam posts and beams. Tolerances were so tight that an entire floor was lifted by a crane and locked into place in less than five days.
Ceilings are 9.5 feet (2.9 m) high and the Douglas fir lower layer of the CLT panels is exposed. To prevent the transmission of sound between units, the same CLT panels cannot be exposed as floors of the units above. Instead, they are coated with 1.5 inches (3.8 cm) of gypcrete, a lightweight concrete floated into place on top of which are 1.5 inches (3.8 cm) of sound insulation board and a one-eighth-inch (3.1 mm) rubber mat under engineered oak flooring.
Structural loads are borne by a grid of glulam posts tied to the deep piles onto which CLT panels are lifted and locked into place over steel tubes welded onto heavy steel plates attached to the ends of the columns. (Kaiser Group)
Advantages of CLT
Kaiser found the following reasons to experiment with a tower built with CLT panels:
• They match steel and concrete in structural performance, but are only 20 percent of their weight and allow for the use of smaller cranes.
• The panels thermally outperform concrete and steel.
• They are seismically resilient.
• Panels are prefabricated off site during foundation construction and are shipped for just-in-time scheduling, reducing the need for on-site storage.
• Using CLT can shorten construction schedules by up to 40 percent, reducing construction loan interest and land carrying costs, allowing units to be sold or rented earlier, which increases absorption and cash flow.
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General information
Address: 3498 North Williams Ave
Town or city: Portland, Oregon
Country: United States
Coordinates: 45.54814°N 122.66645°W
Height: 85 feet
Technical details
Material: Cross laminated timber
Floor count: 8
Design and construction
Developer: Ben Kaiser
Other designer: Path Architecture
Main contractor: Design Awards
Known for: Tallest wood building in the United States
Carbon12 is a wooden building in north Portland, Oregon, in the United States. The 8-story structure built with Oregon-made cross laminated timber became the tallest wood building in the United States, upon its completion.
Carbon12 is located in north Portland, Oregon, in the United States, on the corner of North Williams Avenue and Northeast Fremont Street.
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See also
• ATLAS-I the largest wooden structure, made from glued laminated timber
• Framework (building)
• List of tallest wooden buildings
The Wiki linked to this article:
Updated Apr 30, 2017; Posted Apr 30, 2017
For engineers and architects only:
I specifically thought of the complex, 600 year old hammer beam wood ceiling/roof at Westminster Hall. Even with all of our modern knowledge and technologies, is it even possible to replicate such wonders? (some detail info below the photo from the Parliament web site)
In redesigning the roof, Herland fashioned great oak beams to serve as horizontal supports fixed to the walls (which Yevele strengthened by massive buttresses). Wooden arches joined to the top of these beams met centrally in a span of 18 metres (60 feet) or more.
Onto these arches the craftsmen built the slopes of the roof, with its weight borne by the hammer-beams supported in their turn by the buttressed walls.
The construction of the roof was an exceedingly complex and dangerous operation, given the size and weight of the timber and the great heights they had to be lifted to (about 28 metres, or 92 feet). But the result, as we see it after nearly 600 years, is a vast, clear space unobstructed by a single column.
The roof's timberwork was entirely framed near Farnham in Surrey. A large number of wagons and barges delivered the jointed timbers to Westminster, weighing some 660 tons, for assembly.
Also there is much expertise in France and the rest of Europe in restoring these old structures. The European architects and engineers have many opportunities to restore 500+ year-old buildings that don't even exist here in America.
We could learn a lot from them, and many American architectural students do study in Europe while getting their degree from an American university. There will be a wide interest in the restoration of Notre-Dame Cathedral while the work is going on, I'm sure of it.
As you say, the modern materials are better and more environmentally friendly than some of the old methods.
Generally, laminated wood used in beams, trusses and arches (rafters) have many superior physical properties to those of steel. Not the least of which is resistance to fire and heat. That may seem nonsensical at first but it isn't. While the flash point of steel is higher than wood, steel loses some important physical characteristics more quickly when heat is introduced. We saw examples of that in the World Trade Center collapse. I've seen photographs of steel beams "melted" and drooping over charred but surviving laminated beams after the fires they experienced were extinguished.
The general population has a elementary understanding of the word "strong". They tend to believe that steel is "stronger" than wood and that's that. But the real story is not so simplistic. Physical properties include hardness, elongation, tensile strength, compression strength, corrosion resistance et al. Additionally, laminating can negate some important isotropic characteristics of wood. Cost and weight also need to be considered (cost, in this case, not so much 
).
Is a blade of grass "stronger" than a tree in a hurricane? Its superior flexibility is a "strength" when exposed to high winds.
Laminated wood will be used to replace the old timbers.
As I recall the ceiling is mostly stone, with some painted areas, not sure but those might be wood.
So that would be replaceable with fire resistant materials, either the same or a similar look.
The attic, which seems to be where the large beams were should be replaced by materials that are fire resistant rather than cutting down large trees.
As to the roof, most descriptions are of wood and lead and that clearly made it vulnerable, so materials that would approximate the look, but provide more protection seem a better choice. They might also help by not being as heavy and, so, not putting as much stress on the rest of the building?
Like you, I have no expertise in this area, but am just thinking about what would be the best choices for future generations to be able to appreciate this wonderful place.
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