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]

It looks at first glance like there was nowhere near enough cables to hold the legs from breaking. I interpret the crack in an area that should be under compression to support that conclusion.

 

[Ingenuity]

RandomTaskkk:

Thanks for posting that link.

Two images from that link that seem to support the more probable cause being failure of the tie-beam:

1] Exceptionally small quantity of post-tensioning within the tie-beam:

2] Significantly-sized vertical crack, that appears to be inboard of the tower column, within the web-diaphragm:

Also, it has been previously reported that similar cracks (and pending failure/collapse?) have been observed in the other tower - so this further suggests the tie-beam is the probable cause. However, granted, that all aspects need to be investigated, including foundations.

 

[JStephen]

I assume the crack shown IS in the existing/other tower.

 

[Ingenuity]

I assume the crack shown IS in the existing/other tower.

One would hope so - otherwise it was negligent to NOT report and act upon such a crack BEFORE the collapse.

 

[IRstuff]

"One would hope so - otherwise it was negligent to NOT report and act upon such a crack BEFORE the collapse.

It would be oddly coincidental for the crack to be the existing tower and only to have appeared AFTER the collapse. I'm tempted to think that the cracks existed and were explained away by management intent on completing the bridge before the overrun got much worse.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[3DDave]

In Engineers of Dreams a cantilever bridge is noted by on site people as having bent members over period of months. At first it was thought that they were arriving already bent, so the plan was to carefully note if any new members were bent before installation. It got bad enough that workers were refusing to show up.

The consulting engineer, who had initially declined to participate due to health reasons and remained in his home hundreds of miles away, was contacted multiple times and for reasons that are unclear found excuses. When the worker situation became critical he was contacted again. He eventually sent back word to cease work and vacate the bridge.

While those responsible for the site discussed what to do, the bridge collapsed, taking 86 workers with it and killing 75 of them.

I found another report, "Collapse of the Quebec Bridge, 1907.pdf" at
https:\\engagedscholarship.csuohio.edu/cgi/viewcontent.cgi?article=1020&context=encee_facpub

Similarly the Shuttle O-ring failure.

People get used to unexpected failure and start to ignore it because nothing bad has happened yet.

 

[IRstuff]

The cable reinforcement looks sketchy to me; there appears to be as many as there are in my post-tensioned slab, which is not under anywhere near the same tension stresses.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[Ingenuity]

...there appears to be as many as there are in my post-tensioned slab...

And if you slab (on-grade) is with UNbonded PT, it is probably cracked too!

 

[X4vier]

Primer reporte Técnico de Mexpresa

First Report of Mexpresa.

There was only twelve 0.6" tendons in the tension direction and 122 tendons in transversal orientation.

 

[Agent666]

Thanks for that, I've run it through OCR and google translate to get a rough english version which you can sort of follow through and get the idea of whats going on. (quality of the scan is quite low though which impacts on the accuracy of this process)

I would hazard to guess that something must have seriously gone wrong with the design for the cross tie to have that low level of reinforcement. Guess time will tell why it made it through into the construction.

 

[waross]

Page 14;
The existing prestress in the braces is....................316.92 ton which is less than existing tension load of 375.48 ton.....
The remaining tower is cracking and has been declared in imminent danger of collapse.

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

 

[X4vier]

The cost of this collapsed bridge was only 25 millon dollars.
Can probably this low cost may one of the cause.
Constructors can't contract suitable proffesionals with these low costs?

 

[Ingenuity]

The cost of this collapsed bridge was only 25 millon dollars.

What is your source for the $25M?

Others have previously posted that the bridge cost was in the billions.

 

[racookpe1978]

Well, the entire road construction cost was quoted as billions above, but 25 million for one bridge (even down south) seems much too low.

 

[X4vier]

El-puente-de-Chirajara-costo-72000-millones-de-pesos
That's around 25 millions!
Maybe the low cost can be a indirect cause of Collapse. Because contractor can see his profit reduced by hiring ideal staff.

 

[BrianPetersen]

"Too cheap to be good" is a close relative of "too good to be true".

 

[LittleInch]

The article also says the other structure is Ok!!

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[IRstuff]

The article is nearly 2 months old, so probably not a reliable source of engineering material anymore.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[X4vier]

The article also says the other structure is Ok!!

What other structure? The other tower?

 

[X4vier]

The article is nearly 2 months old, so probably not a reliable source of engineering material anymore.

Why do you think is not reliable? It's a joke?