WI - 35W bridge in Minneapolis collapses!

[Trino]

http://kstp.com/article/stories/s156988.shtml?cat=63.shtml?cat=1

Oh, gosh, now we can blame the pigeons!

 

[Mysticchic]

HI Greta. Did you fly in the private plane again? One thing I love is the NTSB loves to talk.

 

[southcitymom]

I don't see it as keeping my head buried in the sand, but I'm not going to live my life in fear and cry terrorism every time something bad happens. What a foolish and sad way to live.

:clap: :clap: :clap: :clap: :clap:

 

[sleuthin4fun]

The one thing that I keep thinking about is that this bridge was designed and built over 40 years ago. I am sure that they allowed for population growth to some extent but, did they ever expect Minn to grow as it has? Was it truely built to handle all that weight?

Also, I read on the FOX ticker that this bridge was declared unsafe in 1990. 17 years is a long time to wait to fix a bridge. JMO

 

[Buzz Mills]

The one thing that I keep thinking about is that this bridge was designed and built over 40 years ago. I am sure that they allowed for population growth to some extent but, did they ever expect Minn to grow as it has? Was it truely built to handle all that weight?

Also, I read on the FOX ticker that this bridge was declared unsafe in 1990. 17 years is a long time to wait to fix a bridge. JMO

Fox has a habit of saying things that aren't true. In example, they kept using the word explosion, despite the person they were interviewing not using that word at all.

 

[cheko1]

The one thing that I keep thinking about is that this bridge was designed and built over 40 years ago. I am sure that they allowed for population growth to some extent but, did they ever expect Minn to grow as it has? Was it truely built to handle all that weight?

Also, I read on the FOX ticker that this bridge was declared unsafe in 1990. 17 years is a long time to wait to fix a bridge. JMO

Thats just the reason some heads will role over this disaster.

My son said PCI (a company) was working on the south side of bridge. He stated there were at least 8 workers who were jack hammering, taking out row bar & resurfacing / I think thats what he called it. He said you get that many on the bridge jack hammering its like a mini earthquake.

He figures the Engineers etc will place all blame on PCI. He said they'll find some way to shift the blame off the Government. Sounds about right!!!!

 

[JBean]

The one thing that I keep thinking about is that this bridge was designed and built over 40 years ago. I am sure that they allowed for population growth to some extent but, did they ever expect Minn to grow as it has? Was it truely built to handle all that weight?

Also, I read on the FOX ticker that this bridge was declared unsafe in 1990. 17 years is a long time to wait to fix a bridge. JMO

Is 40 years really that old for a bridge? Doesn't seem like it.

 

[Mysticchic]

Wasn't the Brooklyn Bridge built in the late 1800's?

 

[JBean]

I don't think the workers had anything to do with it. Seems their work was just so superficial, nothing structural or critical in any way.

I wonder if this is going to go back to initial construction and if any serious corner cutting went on originally.
Has anyone heard if that is even on the radar?

 

[Buzz Mills]

I don't think the workers had anything to do with it. Seems their work was just so superficial, nothing structural or critical in any way.

I wonder if this is going to go back to initial construction and if any serious corner cutting went on originally.
Has anyone heard if that is even on the radar?

The bridge was designed with single points of failure, rather than the highly preferred redundancy in safety. Only two lanes were open in each direction, so it wasn't overloaded; however this could have caused an imbalanced load, depending on the structure, and which lanes were open. Whether the construction/resurfacing is involved is dependent on how much of the roadbed they were removing at given points. I've heard conflicting reports as to whether construction was still going on at 6:00PM--there are always harmonics that could be involved. and the train was passing by underneath the bridge at the time.

 

[Buzz Mills]

Is 40 years really that old for a bridge? Doesn't seem like it.

40 years old is relatively new as far as bridges go. But with those cold MN winters, and warm summers??

 

[JBean]

40 years old is relatively new as far as bridges go. But with those cold MN winters, and warm summers??

what about water eroding away the bridge at the bottom? Is that a possibility?

 

[JBean]

sorry if I am asking dumb questions or things you all have discussed. I have been able to watch zero news coverage and am trying to catch up.

 

[Buzz Mills]

what about water eroding away the bridge at the bottom? Is that a possibility?

Could be. We haven't seen enough of the support design, and placement. Anything is possible at this point.

 

[JBean]

The bridge was designed with single points of failure, rather than the highly preferred redundancy in safety. Only two lanes were open in each direction, so it wasn't overloaded; however this could have caused an imbalanced load, depending on the structure, and which lanes were open. Whether the construction/resurfacing is involved is dependent on how much of the roadbed they were removing at given points. I've heard conflicting reports as to whether construction was still going on at 6:00PM--there are always harmonics that could be involved. and the train was passing by underneath the bridge at the time.

The perfect storm.

 

[JBean]

Could be. We haven't seen enough of the support design, and placement. Anything is possible at this point.

wasn't this a factor in another bridge collapse years ago? I am trying to recall and I know it had to do with the waters effect on the supporting structures over time.

 

[JBean]

TEN YEARS SINCE MAJOR BRIDGE COLLAPSE

The catastrophic collapse of the Interstate 90 crossing of Schoharie Creek near Amsterdam, NY on April 5, 1987 was one of the most severe bridge failures in the United States. Two spans of the bridge fell into the flood waters after a pier, which supported the spans was undermined by scour. Before motorists could be warned, five vehicles plunged into the creek and 10 persons were killed. The National Transportation Safety Board concluded that the bridge footings were vulnerable to scour because of inadequate riprap around the base of the piers and a relatively shallow foundation. The I-90 collapse focused national attention on the vulnerability of bridges to failure from scour and resulted in revisions to design, maintenance, and inspection guidelines.

http://ny.water.usgs.gov/projects/scour/text.html

 

[JBean]

13.5 Bridge Scour

The most common mobile boundary analysis required of the engineer is likely to be the evaluation of scour impacts on existing or new bridges. In the United States, nearly 600,000 bridges carry the nation's highways over obstacles. More than 80 percent of these obstacles are creeks, rivers, and streams. An evaluation of bridge safety against scour is necessary because the bridge location on the stream is fixed, but the stream may scour channel material through the bridge reach and move laterally in the floodplain. The economic life of a bridge is often taken as 50 years following construction, but the actual life could be much longer. Therefore, an adequate evaluation of scour potential is quite important.
The analytical tools to address erosion and scour impacts at bridges were largely lacking until the 1960s. Early scour prediction equations and sediment transport models were available, but the analysis of a specific flood event to compute expected scour was seldom performed. This lack of analysis was mainly due to poor understanding of the physical process of bridge scour, the lack of adequate information for all the variables needed for such an analysis, and the inability to accurately model significant geometry changes for short-duration flood events.
Two major bridge failures in 1987 and 1989 emphasized the need for improved scour analyses, especially for older bridge structures. Erosion and undermining of a spread footing supporting a bridge pier carrying I-90 (the New York State Thruway) over Schoharie Creek resulted in a bridge collapse and the loss of ten lives on April 5, 1987 (NTSB, 1988). On April 1, 1989, a section of the State Highway 51 Bridge over the Hatchie River in Tennessee was destroyed by lateral erosion during a moderate flood, resulting in eight deaths (NTSB, 1990). Both of these disasters are described in more detail later in this section. The need for better bridge inspections and improved evaluation of potential scour situations for both existing and new bridges were mandated soon after the Schoharie Bridge failure (FHWA, 1988).
http://www.haestad.com/library/book...C_RAS&file=Floodplain with HEC-RAS-22-06.html

 

[Buzz Mills]

wasn't this a factor in another bridge collapse years ago? I am trying to recall and I know it had to do with the waters effect on the supporting structures over time.

They had the one where the barge hit the bridge support, and caused the bridge to collapse. It could have easily been prevented with a barrier bumper around the support, as barges do occasionally hit bridge supports.

 

[Buzz Mills]

This bridge had a single arch over the river, with supports on either side of the river---I don't know if the supports are even in the river?? It was built that way so as not to prevent any sizeable river traffic.