Engineering Exam Question

[A Century United]

Engineering Maths Question:

Conditions:

A Hyundai Excavator, weighing 22 tons, firmly chained onto the top of a lowboy trailer and traveling on a motorway.


The extended shovel arm is made of hardened refined steel and the approaching overpass is made of commercial-grade concrete, reinforced with 1 1/2 inch steel rebar spaced at 6 inch intervals in a criss-cross pattern layered at 1 foot vertical spacing.

Solve:
When the excavator arm hits the overpass, how fast do you have to be going to slice the bridge completely in half?


(Assume no effect for headwind and no braking by the driver...)

Extra Credit:
Solve for the time and distance required for the entire rig to come to a complete stop after hitting the overpass at the speed calculated above.


Yes, you can neglect friction.

 

[Bluesmanager]

Err...

Dunno the answer to the question but what's the max speed of that whatever it is?

 

[davewebbsbrain]

Err...

Dunno the answer to the question but what's the max speed of that whatever it is?

I think the header of the Engineering thing was just to make you think it was a serious question before showing you some photos of the damage that can be done when some twonk driving a low loader with a excavator judges a bridge badly!!!


Are you blonde???

 

[Bluesmanager]

No, just cack at maths.

 

[markw]

i think that driver has done this before:P
i would love to come accross that on the m25

 

[M@CC@ 16]

Could be one of them physics triangles.

ie. distance x speed = force (needed to do that damage to that the strength of the bridge)

force/distance = speed

but ain't got a clue if that right

 

[Benfleet A1]

I think the answer is 'Why did the low loader driver not check that the shovel arm was in the traveling position and as he obviously didn't why hasn't he been instantly fired'

 

[Mad Cyril]

Could be one of them physics triangles.

ie. distance x speed = force (needed to do that damage to that the strength of the bridge)

force/distance = speed

but ain't got a clue if that right

Force = mass x acceleration.

Cheers.

 

[BrettieAngell]

That's rather an expensive ****-up methinks!

 

[Firestorm]

Force = mass x acceleration.

Cheers.

Newtons 3rd I believe

 

[TrueBlue]

Them pictures are fake

 

[A Century United]

Them pictures are fake

I've looked through most of the sites which flag up fakes, and I can't find anywhere that says they have been faked...

Did find this news report though:

Hall Street overpass I-70, Hays Kansas, Feb. 14 2006, Ted Bush HDR:
> It will be days or even weeks before a bridge is repaired over
> Interstate Highway 70 that was nearly ripped in half Monday when it was
> struck by a backhoe boom being carried on a flatbed truck.
>
> A bridge evaluation crew from Topeka was on its way to Hays this morning
> to examine the damage, said Kevin Zimmer, Hays, an engineer with the
> Kansas Department of Transportation.
>
> The backhoe, which runs on tracks, was still stuck in the bridge Tuesday
> morning, he said. Eastbound lanes are closed for two miles.
>
> The truck driver, Michael M. Conley, 53, Holcomb, had driven onto the
> Interstate one mile west of the bridge, Zimmer said. The boom of the
> backhoe was about three feet too high for the bridge that crosses Hall
> Street at Hays.
>
> When the bridge was struck at 5:53 p.m. Monday, the boom extended and
> ripped through the concrete bridge deck, Zimmer said.
>
> No one was injured.