OT Big truck - concrete wall

Submitted by LongLiveBo on January 28th, 2010 at 4:04 PM

So I just got this in my email. The following is from the original mailer.

"This was sent by someone who works for the Army Corp. of Engineers.

How many times have you wondered how strong those cement barriers are that you see in front of military base entrances?

From time to time someone asks me what the concrete barriers are in front of controlled and secure buildings. When I tell them that the barriers will stop traffic, even trucks, from approaching the secure building I usually get a look of disbelief.

I've been looking for some film footage like this to prove my point. In this test, the following parameters were used:

Truck = 65,000 lbs.
Speed = 50 mph
Kinetic Energy = 5.5 MILLION ft. lbs.

Stopped in 4 inches! I'm not sure why I find this interesting, but it is ... it must be a guy thing!"

Comments

BiSB

January 28th, 2010 at 4:11 PM ^

Michigan's offense at the moment Molk broke his foot?

But yeah, as a former engineering student (bailed to LS&A), that's what is technically classified as a "shit ton of kinetic energy."

MichMike86

January 28th, 2010 at 4:08 PM ^

What happened to the racism thread? That was a winner. Btw, this is cool as hell. I have always wondered if those barriers would actually prevent a vehicle from hitting a building.

Tacopants

January 28th, 2010 at 4:41 PM ^

As an engineer, I feel as though I'd question if those barriers were sunk into the ground or if they're the portable ones.

Whats the coefficient of friction? I MUST KNOW.

mi_vandal

January 28th, 2010 at 6:28 PM ^

As a registered civil engineer (yay I haz a stamp!) I think it's fairly clear... look at how the wall responds to the force of the truck - it starts standing straight (perpendicular to the ground) and rotates slightly, so that it stands at an angle.

If it wasn't anchored in the ground, the wall would have to stop the truck without the rotation - it would react more like a chain tensing. A bit like this...

These cable barriers are my favorite. Simple, inexpensive, and effective.

The Original Seth

January 28th, 2010 at 5:04 PM ^

See, they have something like this at the little reservists' station on South Industrial, but instead of a solid berm it's those little highway-dividing pieces that are only about 12-14 feet long, and which are definitely not sunk into the ground.

I can't imagine those would have the same efficacy as the barrier in this video.

Though Ann Arbor probably isn't a really big priority on the USDOD suppliers' list.

A Case of Blue

January 29th, 2010 at 12:06 AM ^

Things going boom are so not just a guy thing, or maybe some women don't know how to have fun. I don't know which it is; all I know is that I have been transfixed by early-morning television programs which consist of spectacular car chases/crashes. And Quentin Tarantino films.