From East African city Nairobi. My MD brother-in-law practiced there for 2 decades.
Posted on 03/18/2018 4:58:46 PM PDT by Roman_War_Criminal
Agreed, crazy. The part that fell spanned 7 lanes of traffic. If the central pylon and the cables weren't necessary to support the span then what was their purpose? Aesthetics?
Also, I've read that it was undergoing some kind of test. Any test, by its very nature, has an outcome that is not 100% known. It seems to me it would've been a good idea to halt traffic for the duration of the test.
Learned in grade school that the illness called the bends was discovered while building the Brooklyn Bridge. Decompression from coming up from those underwater caissons caused it.
Anyway, may it stand for another American century!
There are several Roman Aqueducts that still stand and are used for bridges - 2,000 years later.
From East African city Nairobi. My MD brother-in-law practiced there for 2 decades.
“The final design still required a central pylon and cable stays. Construction of the main support/suspension pylon hadn’t even been started.”
I have read that the pylon and cable stays were “aesthetic” and not structural — fake, I guess you could say.
Note that the former British colonies in Africa tend to be much better off than those that were former French or Belgian colonies.
I find that hard to believe. That's a long, heavy span. And, it's got no structural steel in it. All strength is provided by squeezing the concrete via tensioned cables (which apparently they found weren't tensioned enough, which is why they were doing the "test" when it collapsed).
As an analogy, consider a roll of coins. If oriented vertically, they can support a ton or more. If oriented horizontally, they fall apart. However, if you squeeze the coins while you hold them horizontal, they can take some transverse vertical load. That's what was supposed to be going on here.
But, again, looking at the bridge span, there was a rather heavily trussed structure that was going to accept the cable stays, which make sense. But the span platform itself was very thin. That just don't look right to me.
I am not yet convinced that the designers were at not at fault though. I've encountered several significant failures caused by both well known and obscure designers. A PE really doesn't mean that much to me and a university professor even less. In addition, I am always suspicious of design and equipment type by an engineer that has a financial interest in the equipment or technique. Often enough, I have found their recommendations to be biased to the harm of the owner. Full independence is best IMHO.
This was already a weird situation to me in that the street below was apparently open to traffic before testing had even been completed and worse still traffic was going under the bridge while testing was being performed. Weird.
Another example of Obunghole’s $hit Midas touch.
I’m tired of “better mousetraps” that aren’t better, just different (and sometimes cheapened chintzy product).
But then even Free Love isn’t free.
Everything has a cost associated with it.
” I’m always suspicious of falsified materials specification items as well.”
An apartment collapsed in Mexico (?) a few years back.
Beach sand was substituted in the mix.
Beach sand has sea salt that eats rebar; quickly.
Very fatal.
On that bridge, if the tension was lost, it’s a flat out f’n emergency. Like I said, it would have the support strength of a roll of coins if the tension was lost. I wonder if that is what they were checking, although they called it “a test.” If it was, they were checking for a major failure, because I bet it was well known that absent the tensioning, the bridge would fail under its own wait.
Thank you. I so wanted to respond to the “mud and grass” claim but just lacked the energy to deal with that level of ignorance.
Lot of truth in that. One of the reasons India has progressed so much technologically can be traced back to British rule of 150 years during which education flourished.
A Great Read:
The Great Bridge
The Epic Story of the Building of the Brooklyn Bridge
By David McCullough
Yes, that is at the heart of the failure. One can only guess why they thought it would withstand the stress for even a day. There is a reason for the center support. Now we all know what that reason was.
That doesn't sound like a design premise that I'd feel comfortable with.
Too late—I already bought it and, along with a benefactor from Nigeria, will be replacing it. ;)
Agreed, crazy. The part that fell spanned 7 lanes of traffic.
I learned yesterday, that the dormitory for the school (next to the highway) has 16 floors. (No pets allowed).
While adequate parking is required for a Miami-Dade County building permit, the parking lot is located on the opposite side of that very busy highway!
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.