Posted on 03/15/2018 11:32:16 AM PDT by Red Badger
There’s a presser ongoing. It was a bit of a mess until the NTSB chair did some catherding. The upshot is authorities are expecting to find victims under the rubble, no idea how many. There are all kinds of allegations being made about who knew and/or did what, and other than some info about the recovery phase, nobody is providing any answers. Who made the decision to allow traffic to flow, for example, was left unanswered.
UPDATE, March 16, 2018, 11 a.m.: To clarify, Leonor Flores did not work on the FIU-Sweetwater UniversityCity Bridge project in any capacity.
On March 1, 2013, workers began tensioning the 96 ASTM A354 Grade BD rods fabricated in 2008 for two of the East Span’s four shear keys. Shortly after that, it was discovered that 32 of the 96 rods had fractured. Engineers and metallurgists determined the bolts had cracked due to hydrogen embrittlement (HE), which occurs when excess hydrogen, a susceptible material, and tension are present.Last fall, Caltrans bridge inspectors found that more than 400 high-strength steel rods imbedded in the SAS tower’s foundation were not sealed properly, which failed to protect them from the environment. The anchor rods became the focus of attention when Caltrans discovered they were ineffectively grouted by the contractor and sitting in standing water. The threads of one rod stripped through its bottom nut and failed, prompting a thorough investigation of all the rods.
See Failed Anchor Rods on the San Francisco-Oakland Bay Bridge: A Corrosion Discussion by Norm Moriber and Kathy Riggs Larsen, 11/2/2015, Materials Performance Magazine.
I predict we will find at least one engineer onsite at the time of the in-place post-tensioning in this event. Ultimately, the key likely will be which entity was represented by that engineer force.
Make that “entities(s)”.
Trackhoe with jack hammer attachment just demolished the leaning portion of the bridge and it collapsed in a big cloud of dust. Fire department spraying debris to settle dust while trackhoe operator takes a break.
http://miami.cbslocal.com/video/channel/316-live-video/
There goes all the evidence!
It's a complicated story. I've got my own opinions.
There’s an overlying logic to the whole thing, and that is “Accelerated Bridge Construction”. This bridge was designed as a “cable stayed” bridge, and the blueprints and even animated images of this conception have been widely disseminated.
This design includes a tower with “stays” or “cables” or in this case what have been called “pipes”, providing slanting support from a single tower to hold up a a bridge deck which has been designed for this concept.
Enter “ABC” or “Accelerated Bridge Construction”. This stands in conflict with the cable stayed design, which requires a step by step addition of the bridge deck as the stays are added. Very meticulous and time consuming.
So, FIGG decides that this is all unnecessary, and the bridge deck can support itself. So powerful is this suggestion, that it is routinely reported that the bridge is of a “truss design” and that the mast, with its cable stays, are COSMETIC, which I find shocking and astounding.
So in pursuit of this chimera, the bridge deck is installed, still festooned with the “cable stay” connection points, easily visible in the news photos of the installation and subsequent wreckage.
Then, in a matter of hours, the bridge deck starts to disintegrate, as it is under tension, which it was never designed for. All this “testing” is a euphemism for a desperate attempt to save the bridge by compressing the length of the deck with preinstalled cables ( an established technique, but entirely inadequate in this case. ) So the deck sags, and the poor roof, enlisted as a top girder, gives way, as plainly evident in the widely promulgated “collapse video”, and the deck falls like so many bags of sand.
Just a scandal. No excuse. I’m waiting for the call from the networks.
that is the dumbest engineering I have ever seen . There is no way that span could stay up without center support. It is my opinion that it was criminal negligence with massive civil liability in the hundreds of millions.I lived in Miami and it is a corrupted city with huge criminal graft and kick backs. The first wave of Cuban refugees were wonderful people of great value but the second wave and third generation of the first wave were not worth anything. That Contractor was minority and lacked competence and track record but the money flowed from back to the elected officials, in my opinion.All I can say is that the voters of Miami are IDIOTS!!
Well, now we're getting down to it. The whole thing is very plain to me, but we'll have to see how it pans out.
My big worry is some kind of whitewash which lets everybody off the hook.
Well i assure you it will not be revealed!! there will be no investigation. It will be covered up and forgotten. Miami is totally corrupt top to bottom. Jounalism is dead as well,
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