velocity pressures on bridge piers

Question

velocity pressures on bridge piers

cmcarson (Civil/Environmental)

(OP)

19 Sep 03 13:13

I am looking for some basic guidelines on calculating loads on a bridge pier due to 100-yr flood elevations. I assume 10 feet per second velocity, then what??

koodi (Civil/Environmental) · Answer 1 · 2003-09-21 00:40:42

Then you go to the "LOADS" section of your Bible.

The drag is proportional to the square of the velocity--a standard fluid mechanics text will have the same relationship. However, the appropriate drag coefficient is a matter of code.

A real slow drag.

tincan (Civil/Environmental) · Answer 2 · 2003-09-24 17:16:09

Back in the old days, BC (Before Computers) there was a very simple method of determining the effect of flow of water on piers:
        P = KV^2
        P = Pressure on pier in psf
        V = stream velocity in fps
        K = pier shape factor==>2/3 for circular piers
                                1/2 for angle ends L<30deg
                                1 3/8 for square ends.

This was too simple, effective, and useful so AASHTO had to change it.
Best Tincan

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velocity pressures on bridge piers