major Colombia bridge collapses during construction 7

[TomBarsh]

That's the country of Colombia.

A major bridge, 440 metres span, collapsed during construction. Seems to be a cable-stayed bridge with concrete towers and deck. Seems like one tower and span collapsed during construction, killing at least 10 workers.

http://www.msn.com/en-us/news/world...AAuKbGu?li=BBmkt5R&ocid=ientp#image=AAuKLVO|5

A bit more detail and photos showing the scale of the bridge

https://www.nytimes.com/2018/01/16/world/americas/colombia-bridge-collapse.html

 

[3DDave]

The article is not reliable because it claims the other tower, now abandoned, was not compromised. In the time after the article it has been clearly determined that the remaining tower is also failing.

"Aunque es preciso esperar a que terminen las investigaciones, las autoridades señalaron que en principio la parte del puente que permanece en pie no debe estar afectada ya que es una estructura independiente."

Linking the failure to the low price is useless. It's not clear that some larger amount of money would have made up for what appears to be an engineering oversight. There have been a number of top-dollar projects that have suffered huge structural failures. They might have doubled the spending and still not have properly dealt with this failure mode.

 

[X4vier]

ACI COMMITTEE 133. Disaster Reconnaissance was in the site of collapse. The reports from this kind of events must be public to the students and engineers take the preventions in the future. Aren't they public ?

 

[saxman1089]

Article is in Spanish, but the main points are easy to gather from a Google translation.

https://www.elespectador.com/econom...a-podria-tomar-hasta-dos-anos-articulo-752275

 

[X4vier]

the other half was imploded

http://www.eltiempo.com/colombia/otras-ciudades/video-implosion-del-puente-de-chirajara-242196

 

[waross]

Video:
Link

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[IRstuff]

Interesting that they demo'd the crane structure as well; possibly because they deemed it too unsafe to be even near the pylon.

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[JAE]

Did you notice the cable segments shooting off into the trees?

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[3DDave]

I'm a bit surprised it wasn't taken down with artillery instead of risking people going out to plant explosives, but the odds of missing the target is lower when the bombs are strapped to the target.

Any leads on how the design team for the bridge missed what seems like a fundamental free-body load calculation? Was the calc for inches and they used centimeters to order reinforcement?

 

[IRstuff]

Artillery would be like almost literally using a cannon to kill a fly. There is a requirement for simultaneity and precision, which precludes artillery. The only thing that might have come close would be an M1A1, but you'd need several of them to get the specific spots, but the simultaneity is difficult to achieve with something that is manually fired.

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[3DDave]

IRstuff - why simultaneity? Just keep shoving rounds down range until it falls. It's not like they are trying to save surrounding structures in the fall zone.

 

[IRstuff]

"It's not like they are trying to save surrounding structures in the fall zone."

There's a roadway right next to the pylon. I think the bridge was intended to be a bypass for the road, which is still active. They stopped the traffic during the demo. Screencap from the video:

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[3DDave]

IRstuff - the road is not in the fall zone, but it is where artillery might hit, hence concern about missing. As a practical solution, just walk in dummy rounds of matching weight to avoid unexpected damage then send the explosive ones.

I am not sure it's even possible for the bridge to be forced to hit the road - to be tall enough the cables on the road side would have to be steeper than 45 degrees and they don't appear to be. Even to start would require simultaneously severing many cables on the valley side; pretty unlikely. Even the original failure didn't require simultaneous rupture; the rapid progressive failure was enough to drop the bridge nearly straight down and it doesn't look like the explosives did any better in minimizing the debris field.

 

[JStephen]

I don't know how things work in Colombia, but here in the US, demolition contractors don't normally have artillery pieces on hand and the US Army doesn't normally get involved in civilian demolition projects. So regardless of how practical it might be to blow stuff up with artillery, it generally isn't going to happen.

 

[waross]

I don't know how things work in Colombia, but here in the US, demolition contractors don't normally have artillery pieces on hand and the US Army doesn't normally get involved in civilian demolition projects.

After 15 years in Central America I have to say;
"You just can't say."
In one country, There was only one contractor in the country licensed to use explosives.
I would bet that he had access to military hardware, for a price.

Bill
--------------------
"Why not the best?"
Jimmy Carter