Houblog

I started this post as a comment over at Steven Den Beste’s anime site, but it quickly got too long. Rather than abuse his tolerance, I brought it over here to Houblog.

I looked carefully at the security camera’s pictures of the collapse again, this time enlarging the picture.

Concentrate on the bottom of the section of the span visible just to the right of the fence edge (lower arrow). That one area deforms, and a shadow appears, which may be a gap that has opened in the “floor” of the arch. The top deck also appears to be “flat” at tha point, which would support the idea that the bottom of the arch has split at that point. Other than the shadow which definitely appears after the drop starts, I can’t tell for certain if the deformation of the bridge around the two arrows starts before, after, or at the same time as the drop. Of major importance in the film is that, other than the one spot, everything else drops “as is.” It’s all one unit, and it held together until it hit the riverbed. Then a few seconds later, you can see the far approach ramps fall.

Also note pictures 2, 3, and 44 and 47 in this slideshow. The bridge piers are visibly tilted. These appear to be the piers on the far end from the security camera, where we see the ramp falling. Did the ramp shove the pier or did the pier shift and drop the ramp?

As ridiculous as it is for me (a non-technical layman) to speculate, I’m going to do it anyway.

Several theories ran through my head as I looked at this. Originally, I thought a failure in the supports running from the arch to the deck had cascaded across, but that obviously wasn’t the case. For the whole thing to drop as a unit, either the near-side (to the camera) pier gave way, or the bridge’s “feet” somehow shifted off of the pier. Since the near end dropped first, thats where the the final catastrophic failure was, but not necessarily the initial failure that triggered the collapse.

My second theory was that the bottom of the arch gave way near the far pier. Before it could split all the way to the top and “break” that end of the bridge, the span “settled” slightly, pulling the bridge’s “feet” off of the near pier. With one end supported and the other falling, the arch completely separated along the line of the initial break, creating the visible gap.

Problem is, I’m not sure that one holds water either. If an arch breaks, it’s not going to pull inwards, if anything, its feet will shift outwards. (Granted, that could have the same effect–removing the feet from the pier.) But then it occurred to me that something was missing from all the pictures taken after the collapse.

Where is the near-side pier? That’s what took me so long posting this — I kept looking for it, and I can’t find it in the wreckage. No pier, no bridge. But again if it crumbled, is it a a cause or an effect?

Ok, time to shut up and wait on the experts. But forgive me if I can wait for someone to claim that the pier was dynamited by Bush/Cheney/Halliburton/whitey-oppressing-da-man.

This entry was posted on Thursday, August 2nd, 2007 at 11:51 pm and is filed under Current News. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.