Bridge Collapse Caught On Security Video
UPDATE: Here's the video (via Hot Air):
CNN has the video from a security camera near the 35W bridge that catches the collapse. It shows it in the typical four-frames-per-second style of security video, but it quite clearly catches the sequence of the collapse.
The bridge appears to break, as one might guess from the pattern of the rubble, not in the center but as the span goes over the water of the river. The center section drops straight down, and the video briefly shows the cars that went down with it. A few seconds later, that first third of the bridge follows it down. In that first couple of frames, the steel structure buckles dramatically.
One point to note: it does not show the entire span of the bridge. The collapse could have started on the right of the camera, which is not shown. That would be the south end of the bridge; the video looks north across the river. So far, this has not been YouTubed, but if it does I'll post it here.
UPDATE: Here's MnDOT's picture at the edge of the collapse:
UPDATE III: Paul from Wizbang correctly notes that the video looks south, not north, which can he determined by the 10th Street bridge in the view.
Posted by Ed Morrissey on August 2, 2007 6:55 AM | Comments (21) | TrackBacks (3)
Comments (21)
Posted by Paul | August 2, 2007 8:03 AM
Ed,
You live there and I'm a looong way away but isn't that video shooting north?
The reason I ask is that that other bridge looks like it is on the right of the frame. And goolge earth tells me that other bridge is to the east...
The way I figured it, this was shot from the south west corner,
Did I miss something?
Posted by LagunaDave | August 2, 2007 8:30 AM
The first time I saw it, I thought the same thing you did - that the collapse started to the immediate right of the camera.
But looking at the first two frames again, it is odd how quickly the middle of the bridge starts to go, and how it splits so cleanly right in the middle.
There was no break in the trusses there in the middle (i.e. prior to the collapse). It almost seems to me now that the main truss failed near the center, much like the bridge in Milwaukee in 2000 (although that bridge had three rows of girders, and only two fractured, so it didn't collapse).
Posted by Peter Hoh | August 2, 2007 8:47 AM
That video is looking northeast, away from downtown. The woman's shadow would be pointing due east. The school bus would have been to the right of the video camera.
From the looks of it, the bridge seems to have fewer cars on it than I imagined when I heard the reports that traffic was bumper-to-bumper.
Posted by Teresa | August 2, 2007 8:57 AM
I had the same thought as Peter. The news media keeps talking about bumper to bumper traffic, but it did not look as if there were that many cars on the bridge from the video. Nor for that matter from the cars remaining on top of the rubble this morning. Hopefully the loss of life will be less than what was initially feared.
Posted by Neo | August 2, 2007 9:04 AM
Note that the girders just to the right of the top of the chain link fence are already buckling in the first frame of the video.
Posted by Neo | August 2, 2007 9:11 AM
The most scary part is that the section of the bridge in the distance stands for a bit after the center section drops, then it moments later drops as well.
It looks like the girders on the bottom of the inverted tressel of the center section buckled first (see post above), then the super structure compressed inward causing the entire center section to fail off it supports.
Posted by cirby | August 2, 2007 9:15 AM
It's like I said before - one of the supports seems to have failed. With this sort of bridge, that sets off a whole series of events leading to an overall collapse.
Once the first "leg" goes, the adjoining support suddenly has a double load, combined with a massive torque it wasn't designed to handle, so that part of the structure tends to fail as one piece.
Posted by Flash | August 2, 2007 9:55 AM
When will MN DOT release their video footage. There has to be a few different angle of it considering the number of cameras on that section of freeway.
Flash
Centrisity.com
Posted by Paul | August 2, 2007 10:22 AM
UPDATE III: Paul from Wizbang correctly notes that the video looks south, not north, which can he determined by the 10th Street bridge in the view.
No, you've still got this bass-ackwards. The view is to the north-northeast. Note morning shadows and 10th St. Bridge to the right hand side, downstream.
Posted by Neo | August 2, 2007 10:49 AM
Note that the girders just to the right of the top of the chain link fence are already buckling in the first frame of the video. The buckling occurs just below where the road deck of the center section "folds" later in the sequence.
I bet that the initial problem that caused the bridge to collapse with be determined to be an undermining of the support (visible in the video between the two section that collapse) by erosion of the water of the Mississippi.
Also, if you look carefully, there appears to be some puffs below the road deck, showing the compression of the steel below rubbing the concrete above. I bet some of the conspiracy nuts will claim this was part of a "controlled explosion" to bring the bridge down.
Posted by Hans | August 2, 2007 10:49 AM
Looks to me like there are plenty of cars on the bridge as it falls. It also looks like at least one person, maybe two, survived the fall and were on their feet within seconds of the span hitting the water. Check out the video at about the 35 second point where the girl is recrossing the screen moving toward our right. Someone is moving from the north side of the down span on the southbound side toward the south. Could it be a construction worker who survived? Someone who managed to get our of their car soon after the fall? Whoever it is, I'd love to hear their story. Amazing.
I lived five blocks from this bridge throughout college and seeing it down like this is very upsetting. I pray for everyone involved.
Posted by Neo | August 2, 2007 10:57 AM
It appears that the best part of the security video is that part just before the CNN clip.
Posted by Loren | August 2, 2007 11:30 AM
I think update 3 is incorrect, since that standing bridge is east of the collapsed 35w bridge. So I believe the video is looking north.
Neo, none of the brdge supports are in the water, and all supports are still standing.
Posted by Mike Porter | August 2, 2007 11:35 AM
The AP video has the Corps of Engineers identifier, indicating that the video was taken from near the lock on the south side, looking north.
The collapse starts from the right in the video, indicating a falure initiation on the south side. In the photos, the trunnions are missing from the tops of the pylons on the south side, but are still there on the north side. Also the east pylon on the south side appears to be shorter that the west pylon. Finally, the roadway fell to the east on the south end. All of this would point to a failure of in the region the east pylon on the south side.
Posted by Loren | August 2, 2007 11:35 AM
I think update 3 is incorrect, since that standing bridge is east of the collapsed 35w bridge. So I believe the video is looking north.
Neo, none of the brdge supports are in the water, and all supports are still standing.
Posted by Mike Porter | August 2, 2007 11:41 AM
The AP video has the Corps of Engineers identifier, indicating that the video was taken from near the lock on the south side, looking north.
The collapse starts from the right in the video, indicating a falure initiation on the south side. In the photos, the trunnions are missing from the tops of the pylons on the south side, but are still there on the north side. Also the east pylon on the south side appears to be shorter that the west pylon. Finally, the roadway fell to the east on the south end. All of this would point to a failure of in the region the east pylon on the south side.
Posted by Ann | August 2, 2007 12:35 PM
I agree with cirby, this is likely a failure not of the steel (fatigue fractured or not) but of the supports at the near end of the video.
Also, as Neo said, the first frame of the video comes to late. There is already damage visible from frame 1. I'd love to see the video expanded earlier in time to find the point where the damage first becomes noticeable.
That damage in the arch, however, I do not believe is the primary cause, but secondary. Something else caused that buckling. If that was the main cause, then the far section would have fallen as well and at the same time.
Instead we see the entire span fall from the support to that mid-area buckling.
My guess is that the support tipped in towards the river.
One piece of evidence would be if the sections of the bridge on the land side of that pier failed at the same time as the river side. If they did, that would be pretty good evidence that the support slipped away.
Posted by Loren | August 2, 2007 1:51 PM
Ann.
If you look at these pictures before the collapse, you can see the 4 supports of the bridge, none of which are in the water. http://www.visi.com/~jweeks/bridges/pages/ms16.html
Now http://www.foxnews.com/photoessay/photoessay_2152_images/0801072002_M_bridge4.jpg
shows the north end supports still standing.
and although I can't find a the picture now to link, the south end supports are also standing. If you see a picture with the truss lieing sideways, that is the one I remember. Now on the south end, the structure seems to have collapsed sideways to the east, and the west truss is seen lieing sideways. The south west support is seen in the picture i recall just holding up that side. The southest support is standing, with nothing on it.
All of that implies to me that something in the east truss, near the south support failed, and rolled to the east somewhat. The other sections failed due to the loss of the center span, which was holding the side sections in compression towards the banks on each end.
Posted by Loren | August 2, 2007 2:11 PM
I may eat some crow here, this shot of the north supports from another angle
http://ktlkfm.com/cc-common/gallery/thumb.php?src=/export/home//cc-common/mlib/2135/08/2135_11860602021.jpg&wmax=446&hmax=410&quality=90
show the supports at an angle decidedly off of the perpendicular.
Posted by Donna | August 3, 2007 1:06 AM
I think just about everyone on the planet has seen that video by now. http://www.skifactz.com/bridge/ has another clip.
Posted by Peter Hoh | August 3, 2007 9:48 AM
Loren, while the north support pier/foundation is off-kilter after the collapse, The portion of the bridge directly above it remained standing for a few seconds after the rest of the span collapsed. That suggests to me, at least, that the north supports were in place until they were hit by the collapsing superstructure on that side.