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# RE: WHAT IS VALUES OF Cd? HELP ME!!!

• To: seaint(--nospam--at)seaint.org
• Subject: RE: WHAT IS VALUES OF Cd? HELP ME!!!
• From: "Lutz, James" <JLUTZ(--nospam--at)earthtech.com>
• Date: Mon, 4 Dec 2000 08:42:07 -0800

```I found a copy of Figure 17.4B in the 15th edition that appears to have
been omitted in the later version. It's a series of curves that plots Cd
versus H/Bd. The curves are plotted from an equation that is shown on the
chart, so you can calculate it yourself. The formula is:

Cd=[1-e^(-2K*mu'*H/Bd)]/[2K*mu'] where mu' is the Greek letter and stands
for the coefficient of friction between backfill and trench walls, K is the
active earth coefficient, H is the height of fill above the pipe or box,
and Bd is the horizontal width of the trench at the top of the pipe or box.
If you can't interpret the above formula, send me your fax number and I'll
send you the figure.

-----Original Message-----
From: Y.I.Jang [mailto:lionfox(--nospam--at)shinbiro.com]
Sent: Sunday, December 03, 2000 7:45 PM
To: seaint(--nospam--at)seaint.org
Subject: WHAT IS VALUES OF Cd? HELP ME!!!

SomeBody HELP ME!

IN ASSHTO specifications,  I would like to ask,

In standard specifications for highway bridges, 16th 1996. Section 17
soil_reinforced concrete structure interaction system
17.6 Reinforced concrete box, cast in place.
17.6.4.2.2 Trench Installations

In this case Spec. said that "Values of Cd can obtained form Figure 17.4B"
but that figure don't show the Cd.

And so, 17.1.2 Notations describe Cd=load coefficient for trench
installations(Article 17.4.4) but I can not find Article 17.4.4 in this
book.

How can i get the Cd coefficent value?

Moreover, how can i consider the slope of excavation line, another concept
to Figure17.6.A. ?

* like this
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