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Dave Mellor NJ

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Guest Skyking
That last video is interesting to an engineer.

I don't know the specifics of rack design, but

it is a poor design when the removal of one

element results in progressive collapse.

Progressive collapse is one failure mode which

engineers should design against.

Apparently nothing was bolted, probably was relying on just the pressed in hooks. Not good!! I'm sure someone was fired.

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That last video is interesting to an engineer.

I don't know the specifics of rack design, but

it is a poor design when the removal of one

element results in progressive collapse.

Progressive collapse is one failure mode which

engineers should design against.

Actually engineers DO study 'progressive collapse' in huge building demolition. It is an engineering science that can take 6 months to a year to implement, depending on the size and amount of stories of the structure. After strategically weakening the load-bearing walls, explosives are then placed in key areas and set to go off seconds to milli-seconds apart to progressively collapse a huge building unto itself with little, or no damage to the neighboring area.

Craig

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Interesting point about progressive collapse in demolition, Dave!

While a building is in use, though, progressive collapse is something

which isn't wanted! There was a case in Canada (in the 1960's,

I believe) where a woman was using her gas oven; it exploded and

took out a wall on an upper story of her high-rise apartment;

consequently the entire corner of that high-rise building, from roof to road,

collapsed.

Today, if one part of a building collapses, it shouldn't take the entire

building with it!

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That last video is interesting to an engineer.

I don't know the specifics of rack design, but

it is a poor design when the removal of one

element results in progressive collapse.

Progressive collapse is one failure mode which

engineers should design against.

Most storage rack installations are structurally designed to a fine line and are not designed to tolerate much damage. With that said, many of these storage rack systems are not even installed properly. Rack uprights (columns) are often not even bolted to the floor, and this makes them even more vulnerable to failure in column if struck from the side. Just a little displacement from vertical of an upright could cause a failure, and since structural redundancy is usually not part of the overall design of the rack system, collapse often results. Many rack systems employ tab-in-slot connections, which are fine up to a point. I have encountered rack installations utilizing bolted connections, but with the bolts only hand tight ... if that. In short, rack collapse is not unusual after a good hit with a heavy fork lift.

Most designs look good on paper, but there is no design that can withstand a poor installation or an act of creative stupidity on the part of us Human Beings.

Just my opinion,

Grog

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Guest Skyking

I would love to know some of the stories that belong to the pictures, like the 50 Ford stuck inside the building or the paint inside the car. That Ford looks new!

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I would love to know some of the stories that belong to the pictures, like the 50 Ford stuck inside the building or the paint inside the car. That Ford looks new!

Looks like the guy with the paint inside hit another car and spilled a pail full.

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Interesting point about progressive collapse in demolition, Dave!

While a building is in use, though, progressive collapse is something

which isn't wanted! There was a case in Canada (in the 1960's,

I believe) where a woman was using her gas oven; it exploded and

took out a wall on an upper story of her high-rise apartment;

consequently the entire corner of that high-rise building, from roof to road,

collapsed.

Today, if one part of a building collapses, it shouldn't take the entire

building with it!

Unfortunately, many of us did witness (either on TV or frightfully in person), the progressive collapse of the twin towers an hour-and-a-half to two hours after they got hit by those planes.

Craig

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