Footers

[Kawana]

This may be a dumb question, but here goes. I was looking a the pictures of Dominator over at RCDB (http://www.rcdb.com/ig4079.htm?picture=4) and I got to wondering, how do the footers not slide out of position? I'm not very well versed on construction but I just assume that they would move. Are they anchored to the existing concrete? Just wondering...

[DeLorean Rider]

What? Are you assuming that they moved the concrete footers from geauga lake?

All the footers you see were poured before the ride was moved, they go very deep into the ground. They're not just sitting on top of the ground.

Also that ride is not built on concrete, its built on a dirt field.

PS. We dont use the word footers around here, the correct word is footings.

[Kawana]

Excardon me, Belinda. <--------(Homestarrunner reference)

I didn't mean move along with the coaster, I meant move whilst the coaster runs along top of the "Footings."

Thanks for the info....

[PKIDelirium]

There are bolts set into the concrete of the footer that stick up out of the top of it. There's a flange on the bottom of the supports with holes in it. The supports are installed by lowering them into the footer with the bolts going through the holes in the flange, and then nuts are threaded on and torqued down.

[DiSab]

Those are poured into large holes in the ground. How deep they do depends on what part of the coaster the footings support. Ergo, the ones for the lift are very deep, while the ones on, say, the final helix are not quite as deep (but still fairly deep).

[CoastersRZ]

The footings run deep into the ground. Sometimes down to bedrock, depending on the bearing capacity of the soil. The structural engineer will design the footings, based on the results of a soil core sample, which tells them how deep the footing has to go, in order to withstand the forces that the ride will generate. The footing has to be designed in such a way so that it can accommodate all of the forces that the ride generates. Since concrete is great in compression, but has little tensile strength, the structural engineer puts reinforcing steel (often called rebar). Steel and concrete have similar thermal properties, which makes their use together allowable.

Of course, I could get into how the steel and concrete can form either a fixed (also called moment or rigid) connection or a pinned connection. But I don`t want to bore anyone with the knowledge I`ve gainged from four structures courses in my architectural education!

Does that make sense. I hope I answered what you were asking about. Your question was a little vague.

[Kawana]

Yeah, from that picture, and my little knowledge of things of this ilk, it looked like they were just sitting on the surface. Now that I know they run deep underground, it makes more sense.