Wednesday, March 21, 2018

Miami concrete pedestrian bridge; Our great system

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2)          3-21-18   The documents show the Florida Department of Transportation told FIU and its contractors in October 2016 to move one of the bridge's main support structures 11 feet (3 meters) north to the edge of a canal, widening the gap between the crossing's end supports and requiring some new structural design.
  Videos of Thursday's collapse show that the concrete, prefabricated segment of the bridge started crumbling on the same end of the span where the tower redesign occurred, two days after an engineer on the project reported cracks in the same location.  The segment that failed had been placed atop the pylon's footing; the taller tower section was to be installed later.  http://www.newsobserver.com/news/business/article206149809.html
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3)       3-20-18    Henry Petroski, a Duke University civil engineering professor, said even seemingly minor changes in a bridge's design can lead to failures.  "Once a design is completed, subsequent modifications tend to be suggested and approved without the full care that went into the original design.  This has happened time and again in bridges and other engineering structures," he said....
Robert Bea, a University of California, Berkeley engineering professor, said:  "However, the movement of the (pylon) footing led to the requirement for one of the temporary steel supports to be relocated to be able to travel on the highway."  http://www.miamiherald.com/news/article206070889.html
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4)   When you think of the bridge type, you probably envision a metal structure—usually used on railroad bridges—that relies on triangular trusses that bear the load of the bridge.  In this case, however, the bridge had concrete trusses.  That’s unusual, says bridge expert John J. Myers, a structural engineering professor at Missouri University of Science and Technology.  “Trusses are more commonly made of steel elements,” he says.  But since concrete is impervious to corrosion and requires less maintenance than steel, he adds, it’s become increasingly popular in all bridge construction in the last few decades. 
Tensioning work is delicate work, says Myers.  “You could create a torsion or eccentricity in the structure,” he says.  But though over-tightened cables can lead to dangerous twisting or cracking, it’s unclear if that’s what happened in this case.
On March 13, the lead engineer on the bridge project left a voicemail with the Florida Department of Transportation notifying the agency of cracking on the north end of the span. Tragically, the message wasn’t retrieved until after the collapse.   https://www.popsci.com/failed-florida-bridge-what-went-wrong#page-2

Read more here: http://www.miamiherald.com/news/article206070889.html#storylink=cpy



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5)

Erik Olson 3-16-18
  Well, if you look at the renderings and then the top of the collapsed bridge, you will note that the cable suspension towers weren't installed.  What is unclear is where the cable towers would have distributed the load to?  That 120' span should have been shored from underneath, with lanes closed, while the towers and suspension cables were installed.
  Typically, a primary cable tower would be at a fulcrum point, sometimes with a structure under it that carries the load all the way down to bedrock, with all the cables being made to the top, and then continuing off to a massive concrete caisson.
  In the renderings, you see a column in the median of the road.  No such column was there when they dropped the bridge into place over the weekend.  In the collapse coverage, you can see that there are large rectangles with bolts protruding on the canopy of the bridge. Ostensibly, these would have been where plates would be installed to catch the dead end of those suspension cables.  None of that suspension material was in place when the bridge was placed over the weekend.
  At minimum, you would think that massive timbers would have been stacked under the center (or more) of that span until the suspension assemblies were placed and tensioned.
People are going to jail, but it will be little comfort to the families of those who died for this stupidity and "innovative" folly.    http://wfae.org/post/nc-engineer-explains-instant-bridges-weighs-bridge-collapse#stream/0
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 6)       Now it's called "Deep State” but the banal Wall Street dictatorship--above all keyed to absolutist monopoly capitalism--is in full dive as usual.  This is why Trump will not okay a real investigation of the Clintons since they also work for Wall Street, also why recently Trump dumped decent Tillerman and brought in as chief economic adviser a guy who recently recommended that people “buy dollars and sell their gold.”   To ice the recent cake Trump congratulates Putin on an “election victory,” and the Western press has no comment!++   So much for the populist mask!—while dictators celebrate together, and big media smirks at the sea of peasants.     -r

++Sen. Ben Sasse (R-NE) on the Senate floor  
...even turned Trump's signature campaign phrase against him, condemning a "Russian despot that aims to make Soviet tyranny great again."
"The President of the United States was wrong to congratulate him, and the White House press secretary was wrong to duck a simple question about whether or not Putin's reelection was free and fair.  It was not.  The American people know that, the Russian people know that and the world knows that," Sasse said.  "The White House refused to speak directly and clearly about this matter; we were weakened as a nation and a tyrant was strengthened."    https://www.politico.com/story/2018/03/21/sasse-trump-putin-russia-479045
         "I called President Putin of Russia to congratulate him on his election victory (in past, Obama called him also).  The Fake News Media is crazed because they wanted me to excoriate him.  They are wrong!  Getting along with Russia (and others) is a good thing, not a bad thing," Trump said.  "They can help solve problems with North Korea, Syria, Ukraine, ISIS, Iran and even the coming Arms Race.  Bush tried to get along, but didn’t have the 'smarts.'  Obama and Clinton tried, but didn’t have the energy or chemistry (remember RESET).  PEACE THROUGH STRENGTH!" he added.
    Sasse's comments on the floor came over an hour after the President's tweets.  He called on members of the Senate to be able to say "basic true things" about what happened Tuesday.  https://www.washingtonexaminer.com/news/congress/ben-sasse-a-tyrant-was-strengthened-when-trump-congratulated-putin
Hey, Putin is not "President" Putin, he's the KGB head; like in China, the Communist Party chief.     -r
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7)       2-11-2018      This development of a two-level or dual state (covert and overt) has been paralleled by two other dualities: the increasing resolution of American society into two classes – the “one percent” and the “ninety-nine percent” – and the bifurcation of the U.S. economy into two aspects: the domestic, still subject to some governmental regulation and taxation, and the international, relatively free from governmental controls.     -Prof. Peter D. Scott   https://www.globalresearch.ca/the-state-the-deep-state-and-the-wall-street-overworld/5372843

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