
Will We Glue Skyscrapers Together in the Future? - jseliger
http://www.citylab.com/tech/2016/03/will-we-glue-skyscrapers-together-in-the-future/474036/
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ChuckFrank
This from the man, Lynn, who said that we'd be making houses the same way we
make shoes. He's a techno carpet bagger. He takes the most current and
promising technologies, from shoe makers, to car makers, and then rails at the
building establishment for not taking that technology and his lead seriously.
When in fact, his actual works are bonded kids toys. And that's the problem
with these guys, they talk big game, but when it comes to implementation, they
barely elicit a shrug.

Structural steel was adopted quickly once it was clear that it was superior to
all other existing construction technologies. The same thing would be true
with glue-this and glue-that, if it turned out the be true. It's not. It's the
architectural equivalent of vapor-ware.

Sorry Herr Lynn, we are still waiting for your shoe houses.

~~~
hinkley
Well, technically it has, considering all the laminated wood beams used in low
rise buildings...

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alejohausner
Boston's Big Dig tunnels used bolts glued with epoxy to hang the heavy roof
panels that hung over the roadway. The epoxy failed catastrophically and the
panels fell on a car, killing the driver.

Analysis of the accident blamed the workers who installed the bolts, but I
think the big lesson is that construction sites are messy, and don't provide
the best environment for the delicate chemical reactions needed to set
adhesives properly.

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brenschluss
This already happens. The glass on the curtain walls of many skyscrapers is
held in place by structural silicon adhesive. Example: Frank Gehry's IAC
building in Manhattan, referenced here [1], using products like this: [2]

[1]
[http://archpaper.com/news/articles.asp?id=185](http://archpaper.com/news/articles.asp?id=185)

[2] [http://www.portafab.com/curtainwall-connecting-
adhesives.htm...](http://www.portafab.com/curtainwall-connecting-
adhesives.html)

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cgriswald
> “The problem is that glue is not a mechanical fastener, [and it] can
> deteriorate over time,” he tells CityLab.

Current materials can rust or rot over time. Water can get in places and cause
failures[1].

The problem, in my uneducated-on-the-topic mind, is that glue seems more
likely to fail all at once or exhibit a cascade failure than mechanical
fasteners.

[1] - [http://www.mercurynews.com/bay-area-
news/ci_28329832/berkele...](http://www.mercurynews.com/bay-area-
news/ci_28329832/berkeley-deck-collapse-irish-consulate-prepares-arrival-
grieving)

~~~
msandford
There's a lot to be said for a mechanical interference that prevents two
things from moving relative to one another. Like say a bolt, in shear (or a
pin). Better still is a bolt that exerts clamp force, thus leaving it far, far
less in shear. Bolts are amazing and I can't see why people think glue is
better. Welding is better, sure, but it's also a lot more permanent.

EDIT: I get why people like glue for things like carbon fiber bikes, etc
because weight is an issue and you can't really bolt it. But for buildings?
That's a different use case.

~~~
JoBrad
I can't speak for other materials, but for wood, a properly glued joint is far
superior to fasteners. The glue combines the wood at the molecular level, so
that the two pieces are one. There are similar glues for plastics, too. I
don't know about metal and mortar, but if such a thing exists, using it would
be much better than bolts or screws.

The one drawback is that, if you have to replace a portion of a structure that
is glued, the process is necessarily destructive. You can limit the
destruction, but you still have to cut the old piece out. It doesn't seem like
this would generally be a problem with buildings, though, as almost every type
of renovation is destructive.

~~~
Tyr42
Welding?

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autopov
In California, building codes are tightly integrated with fire code. For
example, residential roofs cannot be entirely covered with solar panels
because a firefighter may have to punch a hole in the roof to vent a fire.

Has anyone ever witnessed a glue lam beam burn? How would glue fasteners in a
skyscraper perform in a fire? The relevant industry needs to conduct studies
and show proof that it's safe.

Safety is a big bandwagon in the CA Leg., so plenty of good data would be
needed to push innovation into building codes.

Based on my knowledge of how the CA State Fire Marshal works, it'll be 2040 or
later for glue welds make it into CA building codes, if the tech proves to be
viable.

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pvinis
Was I the only one who thought that the article will be about "gluing"
skyscrapers with each other? Like using metal bars or something to make them
less vulnerable to wind and earthquakes, by making them behave as one?

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bofussing
> "People are often content with using the tried and true, code-prescribed
> systems," he said.

Unlike aircraft that are made in a carefully controlled factory environment;
building sites can be harsh places to work and fastening systems have to have
the flexibility and design margins to cope with this.

Unless glues start getting a track record of being significantly better (cost,
strength, resilience) than current fastening systems I doubt we will see much
adoption.

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TrevorJ
Biggest questions I have are: how reliably can this be done in the harsh
environment of a job site, and is it obvious when the application has
failed/or is deteriorating?

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grogenaut
We already do, it's called welding.

~~~
ChuckMcM
However, strictly speaking welding requires bringing metal to a melting point,
allowing it to alloy and then refreeze.

Adhesives typically bond in a chemical way to the materials being attached.
This bonding, whether covalent or ionic, is a separate material between the
bonded materials. And while that can be good for helping materials resist
thermal expansion forces, it can be bad in that the ageing properties of the
adhesive is often dissimilar to the ageing properties of the bonded material.

Given the advent of extensive amounts of computer power to comprehensively
model these properties I could easily see civil engineers adopting adhesives
either as an alternative to, or adjunct to, welding and fastening as a way to
keep structural members together.

For me personally, the discussion of adhesives was the second most interesting
part of my materials science classes after forging/working of steel (I always
wanted to make my own swords).

~~~
grogenaut
Chuck you're thinking about some welds but not all. Many welds are actually
chemical as well as just flowing the metals together. Especially bonds between
different kinds of metals.

Also there are many adhesives that require temperature treatment so where do
you draw the line between "welding" and "adhesives"? Just a thought
experiment. I know there is probbably a strict definition.

However if you've ever used a mig or flood welder, it's really not very far
off of from a hot glue gun or just dumping glue on the thing.

~~~
jdietrich
>However if you've ever used a mig or flood welder, it's really not very far
off of from a hot glue gun or just dumping glue on the thing.

As I understand it, the defining trait of welding (as compared to soldering or
brazing) is that the process fundamentally alters the structure of the
materials being bonded. The bonded faces are not merely adhered together with
a filler material, but become a cohesive whole on a molecular level.

The engineering problems posed by adhesive bonding arise largely because the
properties of three materials must be taken into account - the two materials
to be bonded and the adhesive itself. The adhesive could react chemically with
one or both of the bonded materials, it may be stressed by differences in the
coefficients of thermal expansion etc.

~~~
grogenaut
@jdietrich, while this is generally true there are a bunch of special welds
like silver to steel, aluminum to other metals, etc that have specially
formulated multi element fillers so there's chemistry going on there, it's not
just steel to steel with a slightly different steel filler. Bronze, copper, it
can get interesting.

~~~
nkurz
I can't tell whether you are making a subtle technical point, or if you are
don't understand the terminology the rest of us are using. Commonly defined,
welding involves melting both the base metals, and the joint ends up as strong
as the weaker of the two. Soldering and brazing, on the other hand, melt only
the filler, and the joint strength is limited by the strength of the filler or
its adhesion to one of the metals.

When you say "multi element filler", it seems likely you are saying "welding"
when we think you should be saying "brazing". True welding of dissimilar
metals is sometimes possible, but is not very common, and usually requires
some exotic processes most of us are less familiar with: laser, ultrasonic,
diffusion, explosion. There's description of some of these here:
[http://www.totalmateria.com/page.aspx?ID=CheckArticle&site=k...](http://www.totalmateria.com/page.aspx?ID=CheckArticle&site=ktn&NM=152)

