

Confronting New Madrid, Part 2 - ca98am79
http://idlewords.com/2015/07/confronting_new_madrid_part_2.htm

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mcguire
The article includes the following statement, which got my curiosity up:

" _It would shut down the Federal Express hub at Memphis and flatten large
numbers of the rickety tilt-up warehouses, packed with inventory, that have
grown up like mushrooms around the Memphis facility as companies try to out-
compete each other in shipping speed._ "

The word "tilt-up" was a link to Wikipedia[1], which article includes the
section Risks:

" _In the wake of the 2011 Joplin tornado in which seven people were killed in
a Home Depot when the 100,000 pounds (45 t) panel walls collapsed after the
store was hit by an EF5 tornado, engineers in an article published in The
Kansas City Star criticized the practice. They said that once one wall falls,
it creates a domino effect. [...] Shortly after publication of the Kansas City
Star article, the technical committee of the Tilt-Up Concrete Association
(TCA) formed a task force to investigate the claims presented in the article.
With the cooperation of Home Depot, the task group performed detailed
engineering calculations, research and investigation of the claims posed in
the article. [...] The final report was published on January 12, 2012.[22]_ "

Unfortunately, the Wikipedia article doesn't say what the final report says.
Fortunately, reference 22 has a link[2], and the report's executive summary
has:

" _The Task Force’s findings to date include:_

" _1\. The failure started in the structural steel, steel joist and wide-rib
deck roof system. This roof system is one of the most commonly used systems in
commercial buildings, including those with masonry walls, precast concrete
walls, and almost all forms of wall construction_

" _2\. The Tilt-Up concrete panels performed very well and survived the
extreme loads of the EF-5 event only to collapse after the roof failed due to
lack of bracing mechanism._

" _3\. Tilt-Up construction methods played no role in the failure._

" _4\. The perception that the nearby Wal-Mart store performed better because
it was concrete masonry is false. The Wal-Mart took a glancing blow from the
storm and the Home Depot took a direct hit._ "

In other words, the roof of a large, open building is the weak link.

On the other hand, as a professional programmer, I wonder how well typical
commercial software development effort would perform under similar scrutiny. I
know I haven't ever seen such an effort.

[1]
[https://en.wikipedia.org/wiki/Tilt_up](https://en.wikipedia.org/wiki/Tilt_up)

[2] [http://tilt-up.org/tilt-uptoday/2011/12/19/task-force-
comple...](http://tilt-up.org/tilt-uptoday/2011/12/19/task-force-completes-
investigation/)

~~~
idlewords
You're comparing wind loads to seismic shaking, which stresses the structure
differently. Phyllis explained to me that the problem with tilt-ups is lack of
bracing strength - they're just not designed to be shaken back and forth for a
long time. Compounding the problem is that the joints are very hard to inspect
after the structure is built.

~~~
pronoiac
Hey, the author's here! Were you in the area when Iben Browning predicted a
big earthquake from New Madrid, back in 1990? Did that pique your curiosity
about it?

~~~
idlewords
I don't remember it firsthand, though it must have been in the news. I was 15
at the time and living near Chicago.

Everyone on the trip was cursing the guy's name. I first got curious about New
Madrid sometime in the 2000's after seeing a Wikipedia link, but don't
remember the circumstances.

