Friday, December 19, 2008

Re: wind load on fences/walls

On Dec 19, 2008, at 12:42 PM, Andrew Kester, PE wrote:

> It is funny what brings on the most responses on this list,
> normally beer and politics are the hot buttons..... With fences, a
> definite "where are the bodies?" comes to mind. However, at the
> begining of my career there was locally an incorrectly designed CMU
> screen wall that killed a landscaper who was digging a hole for
> irrigation near or under the footing. It was found to have a very
> small and inadequate footing, that if correctly designed and built
> may have prevented the overturning. But during your average wind
> event you are not taking cover adjacent to your nearest fence or
> CMU wall.

This is really way out of my real line of work, but since no one's
mentioned it yet, failure of such things as board fences in a high
wind creates some pretty dangerous flyiing objects. I know from
personal experience that even a Alberta clipper can carry a sheet
metal shed quite some distance. If the distance includes a plate
glass window, it can tun someone's living room into a very unpleasant
place to be, even if no one's hurt outright. We get straight line
winds of 60 miles an hour every summer during severe weather, and
those winds pick up whatever they choose and put them down anywhere.
These aren't tornadoes--just high winds that accompany heavy
thunderstorms.

I also know a little about the times when hurricanes pick up debris
and hurl it around. I don't remember anything specific about board
fences, but it's not too hard to imagine them sailing around with all
the rest of the loose trash someone forgot to dispose of properly.

Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/members/chrisw/

******* ****** ******* ******** ******* ******* ******* ***
* Read list FAQ at: http://www.seaint.org/list_FAQ.asp
*
* This email was sent to you via Structural Engineers
* Association of Southern California (SEAOSC) server. To
* subscribe (no fee) or UnSubscribe, please go to:
*
* http://www.seaint.org/sealist1.asp
*
* Questions to seaint-ad@seaint.org. Remember, any email you
* send to the list is public domain and may be re-posted
* without your permission. Make sure you visit our web
* site at: http://www.seaint.org
******* ****** ****** ****** ******* ****** ****** ********