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

 

[Spartan5]

It's the same thing as in the image of the still-standing tower:

https://www.msn.com/en-us/news/world/colombia-brid...

I was looking more at the think horizontal line. There is a failure that progresses from there as the video advances. Or maybe not *shrug* I see those two nearest cables to the left slacking, then getting blown outward as debris from a compressive failure there shoot some debris outward. Maybe I'm just a grassy knoll kind of guy. I'll put together a slow animated gif together later. But meanwhile, go to the start of the 18 second mark and slow the youtube down with the settings to 0.25 speed.

 

[IRstuff]

I see it, but it seems to lag the far leg's buckling, and the loss of tension on the cables.

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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[waross]

When the tower legs start to spread, the top rigid joint has to break somewhere. I think that that crack is an effect rather than a cause.

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

 

[LittleInch]

The promised initial report mentioned in the link from j Stephen doesn't seem to have made it. Mind it didn't say which Jan 31 it was supposed to be issued. Nothing turns up in a search unless it's all in Spanish.

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

 

[Ingenuity]

The Columbian government's National Agency of Infrastructure (ANI) released the following statements on 01/18/18 and 01/26/18. Translated it states:

Bogotá, Cundinamarca (@ANI_Colombia), January 18, 2018. - The commitment was established at the meeting led today by the president of the National Agency of Infrastructure (ANI), Dimitri Zaninovich, after the tour of supervision of the activities that are being carried out in the area of ​​the Chirajara viaduct.

"The first and most important thing was to take stock of the attention to the victims. We also ask for permanent psychological and social support for all families at this time of so much pain. And finally, we have asked the Audit Office to provide us with a first report at the latest on January 31 to evaluate the main causes that explain the situation, "said Zaninovich.

He added that only until the investigation is completed will the reality of what happened occur. "Until now we do not know the causes of this event and it is very premature to venture into different hypotheses," said Zaninovich, who was accompanied by civil engineer Jesus Manzo Suarez, Mexican expert in the construction of bridges and viaducts, and recognized world authority in the assembly of cable-stayed.

The Mexican specialist will collaborate, together with more than 30 people of the Interventoría, in the collection of material and documentary analysis.

At the same time, the Office of the Public Prosecutor of the Nation advances the collection of evidence at the scene and will isolate the area completely between one and two weeks. Local authorities asked the general public not to approach the area in the presence of unstable debris.

At the evaluation meeting held on the viaduct, the ANI asked the Coviandes dealer to support the working conditions of more than 130 workers who had been working on the construction of this structure.

With psychological support, Coviandes continues with the accompaniment of the families of the fatal victims. Of the nine injured, eight were discharged and only one remains in a clinic in Bogota, overcoming a mild trauma.

The 459-meter-long viaduct - with three-span cable stayed system - is under construction and had not been put into operation. The ANI will inform in a timely manner the results of the investigations on this fact.

Original Press Release 01/18/18 here.

Bogotá, Cundinamarca (@ANI_Colombia), January 26, 2018. - A group of experts, all belonging to the American Concrete Institute (ACI ), will end Friday's two-day field visit to the Chirajara viaduct. to collect samples that - added to the review and analysis of documents, photos and videos - allow to establish the causes of the collapse of the western structure.

The experts have been able to collate in the place of the facts information received of studies, designs and plans of construction, previous authorization of the authorities.

The ACI is a technical, specialized entity with recognized experience and independence worldwide . "This group of experts, all with great international experience, will collaborate with the National Government to establish the causes of the collapse of one of the structures of the Chirajara viaduct," said the President of the National Infrastructure Agency (ANI), Dimitri Zaninovich.

The scientific team is accompanied by representatives of the ANI and the Interventoría. Once the analysis is finished, it will deliver its conclusions to the ANI, in an estimated time no longer than a month.

The specialists who are in the area belong to the Committee 133 of the ICA, dedicated to the study of the behavior of concrete (or concrete) structures during disasters.

They are experts with doctorate in structures and with extensive international experience in the study, evaluation and diagnosis of failed or collapsed structures.

Santiago Pujol , civil engineer from the National University of Colombia. PhD and professor at Purdue University (Indiana). Walter L. Huber Civil Engineering Research Award from the American Society of Civil Engineers and Chester Paul. Siess Award for Excellence in Structural Research from ACI.

Michael E. Kreger , internationally recognized as a leader in reinforced concrete structures and earthquake engineering. Featured by the American Society of Civil Engineers TY Lin Award in 1991 and 2009 and Arthur J. Boase Award of the Concrete Research Council of the American Concrete Foundation in 2011.

Arturo Schultz , professor of Civil Engineering at the University of Minnesota. BS summa cum laude in Civil Engineering from Southern Methodist University and MS and Ph.D. degrees in Civil Engineering from the University of Illinois at Urbana-Champaign. Collaborator of the Faculty with the Testing Laboratory of Multiaxial Subsets (MAST).

The 459-meter-long viaduct over the Chirajara creek was under construction and had not been put into operation. The ANI will inform in a timely manner the results of the investigations on this unfortunate event.

AMERICAN CONCRETE INSTITUTE (ACI)

The American Concrete Institute (ACI) is a non-profit organization based in Farmington Hills, Michigan, United States, dedicated since 1904 to develop standards, standards and technical recommendations for reinforced concrete.

Original Press Release 01/26/18 here..


Jan 31 has come and gone (as LitteInch stated) - no preliminary technical report/s released thus far, it seems.

 

[Ingenuity]

Further digging...a report has been issued, as per this communique from Ministry of Transportation:

1. After receiving the first report of the intercontrol Interconcesiones on the causes that caused the collapse of the Chirajara viaduct, which identified imminent risks for users of the section adjacent to the collapsed infrastructure on the Bogota - Villavicencio road, at kilometer 62...

Communique dated 02 02 18

Emphasis is mine.

It appears the report has not been released to the public.

 

[Ingenuity]

Well this is interesting...a snip from a tweet dated Jan 31 by Ministry of Transportation.

...Consortium confirmed the imminent fall of the tower of the Chirajara viaduct that is still standing today and that is in an initial state of failure.

Source

And this also dated Jan 31:

Although there are reinforcement techniques that could rescue the structure that remained standing, we recommend making a safe demolition, which avoids the risk for both people and the surrounding structures.

Source

 

[Ingenuity]

...and from this Link: "...in the preliminary ruling of the collapse of the Chirajara bridge, a fault in the cross beam was identified".

 

[hokie66]

Sounds like it is as we suspected. The tie beam is the weak link, but the whole design and construction require scrutiny.

The demolition will be interesting. Drone emplaced explosives? Missile?

 

[JStephen]

Here's a subscriber-only article, if anyone cares to dig into it (I haven't):

https://www.bnamericas.com/en/news/...-to-design-flaw-in-colombian-bridge-collapse1

"Preliminary reports on the collapse of a suspension bridge on Colombia's Bogotá-Villavicencio highway point to an apparent design flaw in one..."

 

[LittleInch]

Not much more detail, but copied here for information.

Preliminary reports on the collapse of a suspension bridge on Colombia's Bogotá-Villavicencio highway point to an apparent design flaw in one of the cross beams of the structure.

The first study, done by the project's auditor Consorcio Interconcesiones with Mexican firm Mexpresa, recommended demolishing the section of the 459m structure that remained after the accident on January 15 that killed nine workers, the transport ministry said via its Twitter account.

Minister Germán Cardona said that concessionaire Coviandes was responsible for the design of the bridge and it must decide if it will demolish the rest of the bridge or repair the structure.
"This concessionaire had the obligation to deliver the bridge by June, so the respective sanctions will be applied, and in case the structure is rebuilt, no resources from the nation will be allocated to it," Cardona said via his office's Twitter account.

The ministry also decided to close the road in order to prevent further accidents.
Meanwhile, Coviandes announced that it will carry out an investigation of its own into accident, and that it has hired US firm Modjeski and Masters to do the studies, daily Portafolio reported.
Work on the highway between capital Bogotá and the city of Villavicencio entails widening and maintaining a 45.5km stretch between El Tablón and Chirajara, including four tunnels and 15 viaducts and bridges. Investment in the stretch is put at 2tn pesos (US$700mn). The work is part of the government's 4G highways program.

If the government stands by its public statement, the company will still officially need to re-build the bridge at its own cost ( or its insurers).

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

 

[MacGyverS2000]

Just for my own clarification...

This weakness in the currently-standing tower... does it only exist in the standing tower (i.e., may/may not have been caused by the other tower's collapse), or is it a design flaw that likely existed in the collapsed tower, as well (and possibly the cause)?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[12345abc6ttyui67]

I didn't see it explicitly written down, but my take is that they have identified a design flaw applicable to both towers, hence why the other must also be demolished.

This would make me think the original designers made a mistake in either calculating the applied tension load in the cross beam, or a mistake detailing the connection of the diaphragm to sustain those loads.

I suppose, there could also be defective construction materials or a mistake made on site...

 

[LittleInch]

It's interesting that when you look at other concrete delta towers, very few seem to have this diaphragm wall. It may have been required to reduce the potential for movement during an earthquake, but does seem to be a key difference between this bridge and others.



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

 

[12345abc6ttyui67]

No idea if I am right or not, but my gut tells me they were trying to 'distribute' the tension between the diaphragm and the tower legs over a longer length of the leg. Presumably this leads to a more economical design than would result if you designed for all of the tension at one point in leg as you would do with a tie beam.

The problem I see is that you will have more tension at the top of the diaphragm, with the tension reducing the further down the leg / diaphragm interface you move.

Perhaps they did not account for this properly (e.g. assumed the tension was constant at any point in the diaphragm / leg interface)? This would lead to local overstress at the top of the diaphragm and 'unzipping' of the diaphragm from the tower leg. To me, that is what the video seems to show just below the deck on the furthest leg.

Then again, I might be totally wrong!

 

[LittleInch]

If you look at the picture of the presentation it seems to be talking about the beam (the red box). However maybe the beam was sized assuming some level of tension support from the web and if / when that failed then the tie beam wasn't man enough for the job?

Now which of the structural elements failed first isn't clear - beam or web?

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

 

[bimr]

An expert says that the images, revealed by the CM & newscast, would indicate problems in the construction or design.

The Noticiero CM & revealed a video recorded by a security camera where the Chirajara bridge collapsed. In the circle it is observed how the bases of the structure yield.

Argelino Duran, President of the Colombian Society of Engineers, says that the video would reveal problems in the construction or in the design or in those two variables.

"The support column of the bridge that in that area where the road goes opens in two in a geometry as a diamond begins to move and begin to break the vertices of that rhombus and the diamond, which was elongated, ends up trying to become like square as it falls. Those columns that were part of the diamond did not support the effort that at that time they had to endure, "said Durán.

The engineer Duran, warned that it is necessary to thoroughly review the part of the viaduct that remained standing and does not rule out that it must be demolished.

QBE Seguros, the company that has the policy that protects the construction of the structure of the Chirajara bridge, assures that it will wait for the end of the investigation to respond.

"Our obligation is to investigate the events that occurred, we have a team of internal and external experts who are in the work reviewing what happened and trying to find the cause of the incident," says Antonio Sales, vice president of QBE Seguros.

However, the vice president of the insurer says that the work has several policies and that some of them must already be responding for the nine people who died and the eight who were injured.

"From the insurance point of view, different types of insurance operate here, for the victims are the personal accident policies, the group life policies and the ARL policies," adds Sales.

Only when the investigation is over can the operation be started to remove the debris from the bridge from the bottom of the canyon. For now the government estimates that the collapse of the bridge will delay the delivery of the dual carriageway to Llano for at least two years.

https://noticias.caracoltv.com/colo...a-detalles-sobre-caida-del-viaducto-chirajara

Commission of international experts that analyzed the area warned that what affected the collapsed part could be replicated in the second.

The three American engineers members of the American Concrete Institute who visited the area concluded that the part of the bridge that is still standing presents a latent risk of collapse.

"They have been able to detect that the current bridge say that it is presenting a cracking that can make the collapse of this structure imminent," said Transport Minister Germán Cardona.

For this reason, the Ministry of Transportation informed the Coviandes concessionaire so that it immediately takes measures to guarantee the lives of the people who work in the area.

The president of the ANI explained that the North American experts have extensive experience in collapsed structures around the world and that they will deliver their report in one or two weeks.

https://noticias.caracoltv.com/colo...jara-que-no-se-desplomo-ante-riesgo-inminente

Coviandes, concessionaire of the road between Bogotá and Villavicencio, signed a contract with the American firm Modjeski and Masters (M & M), to carry out the studies and analyzes that allow determining the possible causes that led to the collapse of stack B of the Chirajara bridge, which is part of the works of the double carriageway in the second section of this road corridor.









󰁒Do not rule out demolishing remaining section of Chirajara bridge

The chosen firm will be accompanied by the American Geotechnical Engineering Services (Ages), with the aim of deepening the geotechnical analysis.

According to Coviandes, after doing a study of 20 foreign firms, the selection of Modjeski and Masters was made not only taking into account their great experience in this type of research, but also to "guarantee total independence and transparency in their conclusions".

As part of the contract signed, this February 1 will arrive in the country, to move to the site of the incident, eight officials of the firm, who in addition to their studies of Master and PhD have extensive experience in design and analysis of structures, as well as research forensics of bridge collapse. "The team will be led by M & M vice president Thomas Murphy," added the concessionaire.

The specialists will evaluate the causes of the incident on the Chirajara bridge, study the current condition of the bridge foundations and make an exhaustive review of all the designs of the structure. "The activities include sampling of parts of the collapsed structure and quality verification tests, thorough review of the construction procedures, the results of the tests that served to verify the quality of the works and compliance with standards," added Coviandes.

http://www.eltiempo.com/economia/em...revisar-colapso-de-puente-de-chirajara-177352

 

[Ingenuity]

From Bridge Design & Engineering magazine's website:

The transverse slab contained tensioning strands, but the preliminary report by Mexpresa suggest the section did not contain reinforcement, which could have caused the section to fail...

...Consultants from Mexpresa said that they found no evidence of steel reinforcement, although they had not yet ascertained whether such reinforcement would have been necessary given the presence of the tensioning strands. The experts also highlighted the configuration of the steel stressing tendons, which connected the slab to the columns, where there was a greater number in a longitudinal direction than in the transversal.

Source: Link

 

[hokie66]

Thanks for that link, Ingenuity, but the part you quoted is gibberish, talking about the slab, not the tie beam.

 

[12345abc6ttyui67]

I found the attached file last night. I don't know how highly I rate some of the potential causes noted and am unsure of the validity of some of the data and conclusion, but there are a lot of detailed pictures...