Posted on 08/01/2007 4:28:27 PM PDT by ButThreeLeftsDo
Just turned on the news. 35W bridge collapsed in the Mississippi River. Cars, trucks, semis.....
Fires burning, tanker trucks, at least one school bus, more than ten cars......
Just now breaking.......
Et tu, Brute? I’ve been taken to task by the lesser lights here, but now...by the illustrious Don Joe?
Oh, the humanity!
Southack
wrote:
Why did both sections land flat with no twisting or turning?
Cantilever or pier/footing failure results in a straight vertical drop?
The left sidespan dropped like half a teeter-totter drops when it breaks in half in the center. It lost its counter balancing weight when the mainspan sheared off over the left (east?) pier.
The mainspan seems to have sheared at both ends and dropped straight down, but the images don’t guarantee that so far. I saw some video footage that seemed to show lateral (downstream) deflection on that end of the main span, side span, and supporting steelwork.
Right mainspan pier or associated steelwork, or possibly a right side approach span pier or deck. Either that mainspan pier failed on it’s own, or else something transferred many times design load to that pier very rapidly and it structurally vaporized.
I believe that’s the west end of the bridge, but some confirmation would be helpful as left and right are ambiquous, depending on POV.
Thanks.
Plausible, I suppose . . . not an engineer.
Prayers anyway.
And couldn't a drought cause shifting in the earth or footings? I still think the heat has something to do with it.
I believe there was only one school bus, and all passengers and the driver were evacuated from it. It was not in the water.
I am only stating what I know from watching this since it occurred, and the live broadcasts form KTSP.
~~~~~~~~~~~~~
I hope I’m wrong...
Thanks for your kind comments!
Actually, the KC bridge collapse happened was overloaded, but overloaded through bad design. It was an architecural/engineering error. The structural detail was changed during the project, and an inferior non-redundant detail was substituted. Too much load was transferred to the upper bridge beam. The effect was to double the load on one ‘nut’ that was literally holding up the platform. the beam split apart as people danced across the platform, causing vibrations. As the upper platform collapsed, it brought down the lower bridges.
http://en.wikipedia.org/wiki/Hyatt_Regency_walkway_collapse
Your welcome.
You are quite correct. It has been a long time since that happened. It was overloaded for the way it ended up being built. It was designed to handle the load, it was just the follow through that sucked.
Things were blowing up not down according to the woman in the red car.
[...]
When the bridge dropped, objects and people dropped slightly later, being momentarily suspended in mid-air, making it appear that things were flying upward. No blast.
Actually, she (or some other witness) said that it blew up and out (sideways).
Another witness said they had to leave because of the smell of the explosion, and then did an "unflush the toilet" move by aheming her way to "uh...'truck'" all in one swell foop.
ap update
7 killed in Minneapolis bridge collapse
PATRICK CONDON and GREGG AAMOT, Associated Press Writers
http://news.yahoo.com/s/ap/20070802/ap_on_re_us/minnesota_bridge_collapse
MINNEAPOLIS - An interstate bridge jammed with rush-hour traffic suddenly broke into huge sections and collapsed into the Mississippi River Wednesday, pitching dozens of cars 60 feet into the water and killing at least seven people.
The eight-lane Interstate 35W bridge, a major Minneapolis artery, was in the midst of being repaired and had several lanes closed when it crumbled.
—snip—
The steel-arched bridge, which was built in 1967, rises about 64 feet above the river. An estimated 50 vehicles plunged into the water and onto the land below.
A burning truck and a school bus clung to one slanted slab. The bus had just crossed the bridge before it crumpled into pieces.
Christine Swift’s 10-year-old daughter, Kaleigh, was on the bus returning from a field trip and called her mother. “She was screaming, ‘The bridge collapsed!’” Swift said.
She said a police officer told her all the kids got off the bus safely.
It appeared that the center section of the bridge dropped straight down and pancaked in the middle of the river, leaving several vehicles stranded on a broken island of wreckage. As divers plumbed the waters, other rescuers searched frantically for victims amid broken, zigzagged sections of blacktop. Some of the injured were carried up the riverbanks.
—snip—
Another good hypothesis.
I didn’t write “b4” - I was quoting another poster and added a reply/content to his post.
I heard on one station reports of two school buses going into the river. Not confirmed.
Reporting seven dead now.
No, the threaded rod and the nut and washer pulled though the welded joint in the box-welded beam.
Vehicles are scattered along the broken remains of the Interstate 35W bridge, which stretches between Minneapolis and St. Paul, after it collapsed into the Mississippi River during evening rush hour Wednesday, Aug. 1, 2007, sending vehicles, tons of concrete and twisted metal crashing into the water. (AP Photo/The Star Tribune, Heather Munro)
Emergency personnel respond at the scene of a freeway bridge collapse over the Mississippi River in Minneapolis Wednesday, Aug. 1, 2007. The entire span of the 35W bridge collapsed about 6:05 p.m. where the freeway crosses the river near University Avenue. (AP Photo/Adam Wolf)
Prayers up for families of victims and injured. Pray for them.
Yes.
If the pier or vertical members of the steel truss failed, the bridge would tend to drop straight down.
If the bridge swayed to either side during the fall, it is more indicative that the diagonal bracing between verticals failed first.
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