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  • This is the Ascent Milwaukee.

  • Part of it.

  • I have to move my camera back.

  • This building's 284 feet high, 25 stories, and if you go to the model rooms

  • it looks like a typical,luxury apartment building

  • with prop wine and art.

  • But above the demonstration bed and  view of Milwaukee is a wood ceiling...

  • and wood beams...

  • and wood columns.

  • They're all structural.

  • That's because when I visited...

  • Was that a cool zipper sound?

  • Ascent Milwaukee was finishing construction.

  • When I tell someone I'm working on the tallest timber building in the world

  • they're very surprised to hear that it's in Milwaukee.

  • How does a building, with wood slabs and beams like this, actually happen?

  • It turns out that changing materials  changes the entire construction process.

  • Here's an elegant demonstration of a bag of concrete and some rebar.

  • A lot of big buildings are built using steel beams and columns

  • and PT concrete slab: the PT stands for Post-tension.

  • Basically the steel reinforces the concrete and  tendons are literally pulled on to create tension.

  • PT Slabs are strong

  • relatively easy to build and get

  • often pretty affordable

  • and, maybe most importantly, they're really familiar

  • both to builders and regulators.

  • But they're not very pretty

  • and they can require a lot of energy to make and move around.

  • Mass Timber uses, well...

  • My name is Ricky McClain.

  • I'm a senior technical director with Woodworks.

  • One of the things that the Woodworks  does is tracks the number of projects

  • that are actually being done with mass timber.

  • In 2013, there were say 20-25 projects.

  • Whereas now, we're tracking about 1400 projects in the US.

  • So in terms of overall number of projects done on an annual basis

  • it's still a small percentage

  • but it has been growing significantly.

  • The common way that I think of it is like  vertical products and horizontal products.

  • So for columns and beams

  • it's most often a product called glue laminated timber or glue lam.

  • There's adhesive between each layer pressed together.

  • Sides are planed, so a nice smooth surface.

  • And so that's the gluelam.

  • Beam, two-bys, and columns are the exact same.

  • So the panels, the horizontal panels

  • you can kind of think of that  as like replacing a slab system.

  • Cross laminated timber, CLT, is one of those panel options

  • where you're taking again two bys flat, a layer of of adhesive goes down

  • another layer of two bys flat, but rotated 90 degrees from that first one.

  • So you're creating panels that are 4 to 12 feet wide, 20 to 60 feet long.

  • Mass timber is strong, environmentally in demand

  • both because wood is a renewable material and because sometimes

  • it earns builders environmental credits

  • betteror at least different looking than concrete

  • and arguably better against some  obstacles, like earthquakes and fire.

  • It's also hard to get

  • and way less familiar to builders and regulators

  • But these materials are more than lists of pros and cons.

  • They can change the process of design, sourcing and building

  • for everybody that makes a building a reality.

  • This started as a real estate project, not as mass timber project.

  • The driver was aesthetics.

  • At the time, we didn't know much more than that.

  • It was just a...

  • Isn't it amazing that you can have a tall structure built out of wood

  • and the structure is exposed.”

  • From that one decision, a lot of things about making the building change.

  • The whole process is different.

  • The insurance is different, the financing.

  • And then you start getting into construction

  • and the planning of the building is completely different

  • because you're planning so much of  the building ahead of time digitally.

  • Right? Planning and designing.

  • The biggest design impact might be the BIM

  • which takes design and places it at the top of the construction process.

  • A BIM is a “Building Information Model” a bible of all the stuff in a building.

  • Imagine a blueprint that's 3D and super detailed.

  • We had 60 plus pre-construction meetings.

  • That experience right away tells  you that "Hey, this is unusual."

  • We had to do that because...

  • whether the mass timber panels were  being made in Austria or in Canada

  • or in the United States, it doesn't matter.

  • They're being made at the factory.

  • So if something's wrong, you've got a big problem.

  • It was more intense for us.

  • So you're basically building what's called a digital twin to the real building.

  • And in the case of timber, because  so much of it is prefabricated

  • by the end they had literally modeled the building down to the last screw.

  • You always want to get it right  as the structural engineer

  • or as a design team in general

  • but normally if there's an issue, you can cut it

  • or you can go to the shop or you can pour more concrete.

  • This one, it would've been a 5 month delay to the job

  • to get another beam shipped over site.

  • So it really was critical, which was why  we had so many coordination meetings.

  • And because mass timber is so new

  • you have to spend time persuading regulators to trust it, which means...

  • There's actually no sound here.

  • But this is a mass timber building being set on fire.

  • For years, the USDA's Forest Products Lab in Madison, Wisconsin

  • has been testing mass timber

  • like cross-laminated timber in a building they constructed just for this purpose.

  • It performed well.

  • They also test columns, where the  wood naturally forms a char layer

  • that protects a column's stability.

  • For Ascent, regulators wanted them to test

  • if the columns could hold up to three hours of fire.

  • So they burned those too.

  • We did nine columns total of three of each species that we tested.

  • We instrumented them with thermocouples.

  • We lifted the columns out of the furnace and then scraped all of the char layer off.

  • It worked: the columns were fire  resistance rated up to 180 minutes.

  • And we looked at different species

  • because the different species are a little bit different chemically and might char different.

  • Char has been studied for hundreds of years.

  • In general, people know how wood chars.

  • Concrete and steel can be hurt by fire

  • but they're familiar in the United States.

  • That's why, if you look at this video, you can see that this structure

  • like many mass timber structures, is actually a hybrid.

  • The parking garage is concrete

  • and two concrete cores helped get the project  approved more easily than if it were all wood.

  • Once design is over, sourcing begins.

  • You go from buying concrete at Home Depot to moving wood across the world.

  • You're moving these absolutely massive pieces  of wood all over the country

  • And it's trains, planes, automobiles.

  • You know, you're always trying to  figure out what's the quickest way,

  • what's the most effective way, what is the best carbon footprint

  • you know, all of these items.

  • Taylor Cabot's a project manager at Timberlab

  • which helps design and coordinate mass timber projects like Ascent.

  • Timber manufacturing is still  led by Japan, Germany, and Austria

  • and Ascent's timber comes from Austria,

  • which means they had to get every  single piece all the way to Milwaukee.

  • Imagine you're on the Oregon Trail

  • and you have glass panes for your window and you have it in your wagon

  • with like hay around it.

  • And it's like if you break that glass panelike you are not going to get another one.

  • We are moving things across the country.

  • It can be replaced, but you're  talking weeks. Not days.

  • These materials then affect the engineering.

  • It's not like a steel or a concrete building  where I, you know, the architect doesn't care  

  • what what kind of steel I pick or what  kind of concrete as long as it works.

  • The owner really likes this white Austrian spruce.

  • So some of the columns at the baseyou know, to minimize the overall size

  • are a higher grade or they're  a little stronger, stiffer.

  • But that's also more expensive.

  • So as you go up, you sort of use the lower grades

  • as it becomes more cost effective.

  • Traditional construction also isn't affected by stuff like

  • a boat getting stuck in the Suez Canal

  • Our materials didn't go through the Suez Canal

  • but 2 million containers were then held up in transit as well because

  • they were either stuck literally in the  canal, or waiting to get in the canal.

  • Finding a container was like gold.

  • I would be driving in my city

  • and seeing a container sitting in a yard, and I was likeshould we go grab it?

  • All those design and sourcing changes

  • mean building with mass timber is pretty different.

  • Our construction workers here, they would go home at the end of the day

  • and their wives would say

  • "Huh, doesn't even look like you're working today."

  • "You're so clean."

  • And they love that because with the timber you're not working with

  • all this silica dust from concrete and everything like that.

  • You're just working with with wood

  • and you're really not cutting much, if at all.

  • So you're going home clean.

  • Stuff like welding just doesn't happen in a wood building

  • because it'd be a fire hazard.

  • So, screwdrivers become way more important.

  • We would have upwards of 64 16 inch screws.

  • We were using just cordless battery operated tools.

  • We'd only get maybe five or six of those 16 inch screws per battery.

  • We had a pretty substantial battery changing  and charging operation on the working deck

  • as we're installing these screws.

  • So we would have to field install roughly 7000 screws per floor.

  • This is a glue lam column.

  • Below our topping we have our CLT plank and we have some beams

  • that run into the column.

  • So one column may have as much as 64 just CLT to column screws.

  • Because of this, a lot of things change.

  • While it might take 10 days to complete a floor with concrete

  • it could take only 5, using mass timber.

  • There's less skilled labor available.

  • There's this inherent push to to fully  detail out a building beforehand.

  • And so it really helps reduce labor force on site or reduce waste of materials

  • that come out to site as well.

  • And it's this kind of huge shift in the industry where we're saying,

  • we don't need 100 guys to build a building.

  • You know, we might need 30.

  • Or we don't need to bring a bunch  of materials to site and cut them

  • and create a bunch of waste and send the waste away.

  • We can do all that work in factories and then send it out

  • and have it kind of erect in Lincoln log or a Lego set sort of form sort of way.

  • And that goes back to the original  question: how does a wood skyscraper happen?

  • They're the product of a total rethinking  of the process of construction.

  • One of my favorite just anecdotes was that

  • when we framed the first deck of timber and we go up there, and I'm like

  • "What am I sensing?"

  • And I laid down on the deck because it doesn't have the concrete top yet.

  • Right? It's just raw wood.

  • And I lay down and they look at me and they're like

  • "What is wrong with you and what are you doing?"

  • And I said, "Guys, smell it."

  • "It smells like popsicle sticks."

  • And they're like, "You're insane!"

  • And they get down and they're like

  • "Oh, my God, it smells like popsicle sticks."

This is the Ascent Milwaukee.

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