Math Problem..with photos..

[fkovalski]

Math problem:



Subject: Math problem-

A Backhoe weighing 8 tons is on top of a flatbed trailer and heading east on Interstate 70 near Hays, Kansas. The extended shovel arm is made of hardened refined steel & has a 9" cross-section at the narrow dimension. The approaching overpass is made of commercial-grade 4000 psi concrete approx 3' thick, reinforced with 1 1/2 inch steel grade 60 rebar spaced at 6 inch intervals in a criss-cross pattern layered at 1 foot vertical spacing. Assume 70 mph.



Solve:

When the shovel arm hits the overpass, will it cut into the concrete bridge, & if so, how far? (Assume no breaking by the clueless driver... )



Extra Credit:

Solve for the time and distance required for the entire rig to come to a complete stop after hitting the overpass (No... you can't consult the driver. He likely had to have his face scraped off the inside of the windshield. )

 

[starkmr]

No need for the math, I wanna talk to the idiot who gave the driver his CDL.

 

[BarryG]

I have been out to Hays several times this summer and saw them working on the bridge. I wondered what hit it. Now I know. Idiot is an understatement.

 

[me4osu]

Worked on a JD 410 backhoe that hit an overpass on I-35 in Northern Oklahoma when I was in high school. Super-trucker put the thing up on an oilfield float with the boom straight up and pinned with the dipperstick in.

Snapped both swing-rams, king-pins and cracked the transmission housing in two, but did not RIP THE BRIDGE. That is incredible! I certainly would not want to be driving up on an excavator boom parting a bridge in front of me. :--)

 

[fkovalski]

... the idiot ... driver ... CDL.

That's assuming the drive even HAD a CDL!

 

[PC12Driver]

Check out where the bucket hit the bottom of the bridge. The front of the trailer must of had some pretty good air under it before it stopped and settled back down. That would have made for a helluva ride in the tractor as the rears got yanked 10' in the air!



And could you imagine driving across the top of the bridge and having that arm poke up in front of you?

 

[RustyJC]

OOPS!! :{ Doncha just HATE it when stuff like that happens? :-laf



Rusty

 

[fkovalski]

Assume 70 mph.

OK... this is intriguing me... . Look at the 3rd photo. It's approx half way into the lanes. Furthermore...



Assume 15' wide driving lane and another 3' or so of gaurd rail. From initial contact to stop is 70mph to 0 in 18 feet!



That is some quick deceleration!!

 

[fkovalski]

Check out where the bucket hit the bottom of the bridge. The front of the trailer must of had some pretty good air under it before it stopped and settled back down. That would have made for a helluva ride in the tractor as the rears got yanked 10' in the air!... .

Actually, I am thinking that the 'arm' of the bucket assembly rotated back and up into the undeside of the bridge (as you state. ) But, I am thinking that the coresponding reaction might have pushed down on the trailer as it tried to go forward (not sure of this, just trying to picture the motion of it all)

... And could you imagine driving across the top of the bridge and having that arm poke up in front of you?

No kiddin! I was having the theme song of "Jaws" in my head as I read this! :-laf

 

[JoshPeters]

This had been posted once before. I believe someone had said that they are actually supposed to have backhoes like that turned around backwards for that reason. That way if they hit they don't telescope up.



JP

 

[PC12Driver]

Actually, I am thinking that the 'arm' of the bucket assembly rotated back and up into the undeside of the bridge (as you state. ) But, I am thinking that the coresponding reaction might have pushed down on the trailer as it tried to go forward (not sure of this, just trying to picture the motion of it all)

I dunno... there's damage to the top of the cab where the roof is peeled back like it struck the bridge. And the arm would have been pinned closed by the concrete. Also, the rear triples have a nice "taco" effect to them where the trailer bent at the drop from the front being wrenched up. I'm thinking the tractor was flipped to somewhere around Salina...

 

[fkovalski]

... I'm thinking the tractor was flipped to somewhere around Salina...

:-laf :-laf :-laf LOL... . I like that description!

 

[fkovalski]

I dunno... there's damage to the top of the cab where the roof is peeled back like it struck the bridge. ...

Yep, I think you're correct.

 

[E7mack96]

Josh - you are correct. They should be transported with the stick/bucket to the rear. It cuts down on fatalities.

 

[Cummins Pilot]

Wow, I bet that was a wild ride. Would be nice to see it on video.

 

[WCPoe]

Equipment mishaps

Try this.



http://community.webshots.com/album/405519685



There are many at this site.

 

[rbattelle]

I want to know who pays to repair the bridge? Must cost millions.



Ryan

 

[Elite1]

OK, Not to be a smarta&&, but we all know that the piece of machinery in question is not a backhoe at all. The photo's you show are of an excavator.

 

[phloop]

It looks like the damage too the cab did come from the bridge as there is a small :-laf hole just above the cab. I think the track hoe was yanked up as it was drawn up into the bridge by the arm.



It does look like he had it chained down good from the looks of the trailer. If he had not chained it good I don't think that trailer would have the curve too it that it does now.

 

[daytripper63]

Definetely a D. A. D. sufferer

Millions of people suffer everyday of Dumb Azz Disease