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# Re: Was embedded timber post (80 Tons trailer impact on Structure)

• To: seaint(--nospam--at)seaint.org
• Subject: Re: Was embedded timber post (80 Tons trailer impact on Structure)
• From: "David Topete" <d.topete73(--nospam--at)gmail.com>
• Date: Fri, 23 May 2008 11:12:36 -0700

Oh yeah, I forgot the other 3 zeros...  i had seen Joe's post about the embedded posts at K-rails to resist the 10kip force at 30" above road surface.  Thank you for checking my "fuzzy math."

On Fri, May 23, 2008 at 10:41 AM, Casey K. Hemmatyar <khemmatyar(--nospam--at)gmail.com> wrote:
Great David;

Just to refresh your memory, it  has a 28,340 k-ft of Force but not Energy.

Applying Work-Kinetic Energy Theorem:

Wnet = Kf Ki= ½*mv^2

W [Work]= ½*mv^2

m=mass; kg

v= Speed; meter/sec

W=(½) (80*1016)*(70*1.609*1000/3600)^2=39,779,275 Joules (This is "Work")

1 Joule≈0.73756 ft-lb

F [Force]=39,779,275*0.73756/1000=29,340 ft-k

Regards

Casey K. Hemmatyar, SE

___________________________________________________________

From: David Topete [mailto:d.topete73(--nospam--at)gmail.com]
Sent: Friday, May 23, 2008 8:59 AM
To: SEAINT
Subject: Was embedded timber post

http://news.enquirer.com/apps/pbcs.dll/article?AID=/20080521/NEWS01/805210387

If my calcs are correct, an 80-ton trailer at 70 mph creates 26,200 ft-kips of energy.  (F = 1/2 mv^2 if my math serves me correctly... )  That is about 10k at 30".  Or am i way off?

--
David Topete, SE

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David Topete, SE