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The Sky Is Falling! January 3, 2008

Posted by gordonwatts in D0, Fermilab, physics life.

IMG_0013I’m on shift. At D0 this means we are 4 stories underground, in an all concrete building. One of the shifters looked up and saw a single drop of water fall from the drop-ceiling (think those awful ceilings that every school has).

We called the guy responsible for this sort of thing – even though a single drop of water isn’t much of anything, it seemed like a very odd place: in the middle of a room, many feet from any exterior wall.

After a few minutes of investigation we discovered cracks in the concrete floor and water was dripping through from the large AC unit above (which cools our Level 3 computer farm of 1200 CPUs).

No no one wants to sit over in that corner of the control room. ๐Ÿ™‚



1. Andy - January 3, 2008

Holy cow!

2. gordonwatts - January 4, 2008

Well, keep in mind I know nothing about buildings and floors and cracks. In all likelyhood this is just something that requires some sealent. The Level 3 AC that sits above is working overtime and the pan that catchs water got dirty and cloged its drain, and so the water was blowing over onto the floor. At any rate… ๐Ÿ™‚

3. carlbrannen - January 4, 2008

The concrete used in floors like this would normally be a fairly weak type of concrete. It’s used to make a smooth surface rather than to provide strength per se. The strength will be provided by steel girders every 4 to 10 feet or so.

Concrete is prized by engineers for its resistance to compression. It has almost no resistance to tension. And so it is almost always cracked. However, the tension bearing elements in concrete is steel rebar. If you let rebar get wet, eventually it will corrode and convert to the oxide. This expands the rebar and will crack the concrete.

Reporting this to facilities is what you should do, but it’s probably not a big deal.

I have a friend who was sharing a bath with someone when the long term effect of rot caused the bathtub to fall through the joists to the open storage unit below. Unhurt, but naked and cold in a Seattle winter; they had to figure out how to get back inside their locked house without keys.

Things like that are caused by tenants not bothering to report leaks to the management or management not bothering to repair them. My buddy’s house is undergoing the same transformation. I walk quickly through the garage if necessary, and I sit on his toilet only ginerly.

4. gordonwatts - January 4, 2008

I am laughing out loud. Thanks Carl, good post for the middle of the night here…!

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