Author Topic: Technical Thought required....................  (Read 2800 times)

Offline Leftie

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Technical Thought required....................
« on: April 19, 2008, 05:20:04 pm »
This is a bit of a brain teaser to say the least. The younger members will have to do the conversions.

I couldn't find my slide rule or abacus. But I have photographic evidence of the end result.

OK, I received this email from a pall stateside.

ENGINEERING PHYSICS CALCULATION

Problem:

A backhoe weighing 18 tons is on top of a flatbed trailer heading east on Interstate 70 near Hays, Kansas. (The boom and dipper stick is made of 80,000 psi high strength steel and the approaching overpass is made of 4,000 psi concrete, reinforced with 2 layers of 1 inch steel rebar spaced 6 inches each way in both the road deck and bottom of the box-beam bridge section.)

Solve:

When the boom and dipper hits the overpass, how fast does the trailer with the backhoe have to be going to slice the bridge in half? (Assume no headwind and no braking by the driver who is oblivious of the situation . . . )

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 .





See pictures below.............................



































Answer - It doesn't really matter... The point is that the trucking company just bought themselves a bridge.


What would 'elf and safety' say?
« Last Edit: April 20, 2008, 12:16:02 am by Leftie »
At my age, it takes me all night to do what I used to do all night!!!!!!!!!!!
Then, growing old is compulsary, but growing up is just optional.

I don't do GREEN, I've got a 4x4

Offline Perdu

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Re: Technical Thought required....................
« Reply #1 on: April 20, 2008, 12:23:15 am »
oops

 :-[
"Ha ha you can't a fool me, there ain't a no sanity clause!"

Offline redstu

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Re: Technical Thought required....................
« Reply #2 on: April 20, 2008, 08:21:27 am »
Learning - don't take on a Hyundai - it seems to have survived pretty well

Offline Lord Pig-Pen

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Re: Technical Thought required....................
« Reply #3 on: April 22, 2008, 02:11:14 am »
I will consult my old degree notes from Structural Eng.
First impresions are... faster than it was going and stronger chains holding the digger on the trailer.
Is it normal practice in the US to drive with the actor in the up position? ;D
What do you mean dust?.... Thats not dust, this is dust! Ich Habe Honda S2000 and its not mine!

Offline Leftie

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Re: Technical Thought required....................
« Reply #4 on: April 22, 2008, 02:32:08 am »
I will consult my old degree notes from Structural Eng.
First impresions are... faster than it was going and stronger chains holding the digger on the trailer.
Is it normal practice in the US to drive with the actor in the up position? ;D

Normal practice is backacter down.  But I think not low enough for this bridge.

On impact, the BA went up due to 'friction'. Pic 3 shows the hydraulics shot to pieces. Even pulled the ram out.

These are BIG f'ing machines so the haulage Co' should check heights etc.
At my age, it takes me all night to do what I used to do all night!!!!!!!!!!!
Then, growing old is compulsary, but growing up is just optional.

I don't do GREEN, I've got a 4x4