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• To: seaint(--nospam--at)seaint.org
• From: Roger Turk <73527.1356(--nospam--at)compuserve.com>
• Date: Fri, 15 Oct 1999 21:59:23 -0400

```Gabe,

Don't forget the suction coefficient (0.7) acting on the lee side of the wall
and on the lee side of the piping.

Also, don't try to be so precise that you are wrong.  Wind is a very complex
loading condition and the requirements can only be approximated by codes.  As
far as your scenarios go, is there room between the pipes and the wall so
that streamlining can occur?  If not, what about partial streamlining?

So, I would consider the wind pressure and drag coefficient on the piping
(0.8 + 0.7) plus the wind pressure on the wall 0.8K + the drag coefficient,
0.7, where K is a factor to account for streamlining, which is a judgement
factor.

Hope this helps.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Gabe Bohm wrote:

>>I'd like to add a few new elements to the question I posed a couple of days

Consider a solid wall, with lots of platforms, vessels & pipes located just
a few feet in front of the wall, with wind acting perpendicular to the wall.
There is a single wind force resisting system that collects wind pressures
from the wall and everything in front of the wall.

The question is how to determine the total wind load acting on the wind
force resisting system.

The wall and everything that's in front of it form one single process
equipment. Future removal of any item located in front of the wall is
physically impossible. Wind tunnel testing is out of the question.

I can think of two extreme approaches. The minimal approach would be to
apply a Cp coefficient of 0.8 to the windward face of the wall, and that's
it. In other words, everything that's in front of the wall is ignored -
rightly so, one might argue - after all, aren't all those things right
against the wall?

The other extreme would be to apply a Cp coefficient of 0.8 to the wall,
then add wind loads on everything that's in front of the wall, calculated as
if there was no wall behind them. Some may argue that this is "double
dipping", which severely penalizes the wind force resisting system.

You can't go wrong with the second approach, but  there's a price tag there.
Can the first approach be technically justified? Is there something in
between?<<

```