Check out yesterday's Wall Street Journal for a sharp piece of investigative reporting on seemingly shady contributions to Hillary Clinton's campaign.
A businessman named Hsu who is a big backer of Hillary and Democrats seems to have used a working class Chinese family in San Francisco to funnel $55,000 to Clinton's campaign and another 150k in lolly for other Dems. The businessman was an early promoter of "engagement" with the Chinese communist government, the Journal noted.
In today's edition, Hsu claims the contributions were by a man named Paw who is now working for him and that nothing illegal had occurred. Paw's father, a mail carrier, and other members of the Paw family live at an address in San Francisco previously used by Hsu.
The Journal pieces appeared during the transition from Bancroft control to Murdoch takeover. Given Murdoch's own coziness with Chinese reds and his detente with Hillary, it looks like the staff chose their publication time wisely.
Update Aug. 30
Hsu has been a fugitive from California for 15 years, reports the LA Times. He was facing three years in prison in a stockholder swindle. Rather than escaping to Hong Kong, as was assumed, he went to New York and resumed his wheeling and dealing, this time becoming a major Democratic Party contributor.
He was hiding in plain sight, often being photographed at Democratic events. Yet, Clinton's staff evidently did no check on Hsu's background to forestall questions about "Asian moneymen" that dogged her husband's campaign.
Hsu may have felt that being politically connected would protect him, as well it might have, had not the WSJ staff had the nerve to run a story that the incoming Murdoch may well have found objectionable.
I'm also wondering about the source of Hsu's wealth. Did Beijing have anything to do with his obtaining seed money for new ventures? Did a connection with Beijing have anything to do with his ability to evade arrest? These are questions for the FBI, of course -- if we could trust that bureau, which we can't.
Wiretap wobbles
Intelligence chief Mike McConnell's public admission that telecom companies are a crucial part of warrantless wiretapping may have damaged the government's claim that lawsuits against those firms must be barred based on the "state secrets" privilege.
But, even had he not said so, wouldn't introduction of the state secrets argument imply that the telecom companies were involved? So the secrets must be about specific aspects of the raft of surveillance programs authorized by Bush after 9/11. Yet it is hard to believe that judges aren't competent to winnow out those aspects that must remain classified.
Upon signing the bill into law, Bush himself said that he wants Congress to pass better (he meant retroactive) lawsuit liability protection for entities that "allegedly helped" American security. The term "allegedly" was no doubt inserted by a lawyer, but its use is logically absurd. That is, "allegedly" means "yes or no." So if telecom firms didn't help, they don't need liability protection. They only need that protection if they helped the NSA or other spook outfits. So we have Bush and McConnell both in effect lifting the states secret ban when it suits their public policies.
As I said in a Znewz1 circular, though Congress rushed through a bad provisional warrantless wiretap law, what we really see is that the control clique is scrambling to try to regain their accustomed unfettered access to anybody's communications. In the wake of the New York Times' NSA disclosures, a number of news reports pointed out that long before 9/11 feds had enjoyed special "national security" arrangements with telecom firms whereby company executives simply looked the other way and didn't inquire about warrants.
The lawsuits have forced these firms to tighten up and make sure that laws are obeyed. Their best protection against liability is a warrant issued by a court.
But even a crooked judge is not going to grant the unfettered access that spook control freaks, representing the Council of Oligarchs, want. This lack of access may not have much to do with terrorists, but it has a lot to do with the economic advantage that comes with being an insider.
Bush is right about the current law being inadequate: it's inadequate for the oligarchs. Because telecom lawyers will be watching every P and Q for the remaining five months of the interim law's time span. Telecom statisticians, who are top rank, will be, or should be, watching government activity for signs of irregularity that could imply abuse.
The "system" has always relied on the power of intimidation. We can listen in at any time. So don't cross us. But now that effect is greatly weakened. The intimidators and control freaks have to go to all the bother of sending out spook crews to monitor specific political or economic "undesirables."
But even if a pro-oligarch law eventually is passed by Rockefeller and others, the telecom firms could still face hassles. A judge might view a hold-harmless clause with jaundiced eyes if their is sufficient evidence to indicate the firm should have had reason to believe that the government order was illegal. Obeying an illegal order can itself be illegal.
Kryptograff blog back
My Kryptograff blog came back to life (coincidentally with Gonzales' ouster) and after I asked Google/Blogger whether a federal agency had ordered the blog censored.
So far they haven't replied to my email.
That account has been beset with morphing bugs. I take that as a back-handed compliment to our influence.
Fisk joins 9/11 doubters
Go to The Independent and search Fisk to read British journalist Robert Fisk's puzzlement about a number of 9/11 mysteries.
He denies being a witting part of a coverup conspiracy but says some facts are just too hard to ignore. Though his column indicates he doesn't know much about 9/11 inconsistencies, at least we are seeing a shift in attitude by a well-known journalist. And, his paper didn't kill the piece.
In the age of the internet, a British journalist can have quite an impact in America. Remember the Downing Street memos?
Wednesday, August 29, 2007
Tuesday, August 21, 2007
Tenet seen as 9/11 slacker
The CIA's inspector general says George Tenet should be held accountable as the director who failed to institute proper coordination and planning that might have thwarted al Qaeda's attacks of 9/11.
I scanned the executive summary and found that the review team had ignored the truth: that al Qaeda was only a dupe in the attacks which were carried out by federally protected operatives. So the report is essentially worthless and simply tends to maintain the ludicrous fictional account. The IG should be held accountable for helping cover up treason.
It just dawned on me that my kryptograff blog was blacked out at about the same time the IG report was grudgingly released. The CIA hates being forced to declassify things, fearing it will look weak politically. So, maybe spookdom won't look so weak if a media critic's work is censored "coincidentally."
It should be easy enough to prove hacking by comparing my blogs with a random sample of other blogs to see whether the number of bugs on mine indicates a non-random pattern. But, why bother? Big Brother always has a Catch 22 to hide behind anyway.
I scanned the executive summary and found that the review team had ignored the truth: that al Qaeda was only a dupe in the attacks which were carried out by federally protected operatives. So the report is essentially worthless and simply tends to maintain the ludicrous fictional account. The IG should be held accountable for helping cover up treason.
It just dawned on me that my kryptograff blog was blacked out at about the same time the IG report was grudgingly released. The CIA hates being forced to declassify things, fearing it will look weak politically. So, maybe spookdom won't look so weak if a media critic's work is censored "coincidentally."
It should be easy enough to prove hacking by comparing my blogs with a random sample of other blogs to see whether the number of bugs on mine indicates a non-random pattern. But, why bother? Big Brother always has a Catch 22 to hide behind anyway.
Hacking: a form of hate speech
Those who have been playing games with my various blogs seem to be afflicted with one-up-itis, which is part of the control-freak syndrome.
The message is always essentially the same: We detest free speech and our only way to answer is by hacking and censoring.
For example, after I sent out a Znewz1 alert about federal employees censoring and spin-doctoring Wikipedia entries, my kryptograff blog was shut down, supposedly after a spam-hunter program spotted signs of spam. This happened previously to a related blog, but in that case one could still read it. This time not. Well, at least their cover stories are inconsistent...
The blackout was particularly irritating because I was unable to send a link summarizing the NIST's 9/11 collapse scenario for review by a group of scientists, some of whom were engaged in an email discussion of the plausibility of the government's 9/11 claims.
Whenever a particularly vexing bit of censorship (via some alleged bug or other computer "glitch") occurs, it always follows something I have written that threatens media control freaks: those who believe all power has been given unto them or at least who strenuously want others to think that.
Their game is, for one thing, to control the debate in the presidential campaigns. Simple as that.
Most likely suspects: feds operating through one or more cutouts.
The message is always essentially the same: We detest free speech and our only way to answer is by hacking and censoring.
For example, after I sent out a Znewz1 alert about federal employees censoring and spin-doctoring Wikipedia entries, my kryptograff blog was shut down, supposedly after a spam-hunter program spotted signs of spam. This happened previously to a related blog, but in that case one could still read it. This time not. Well, at least their cover stories are inconsistent...
The blackout was particularly irritating because I was unable to send a link summarizing the NIST's 9/11 collapse scenario for review by a group of scientists, some of whom were engaged in an email discussion of the plausibility of the government's 9/11 claims.
Whenever a particularly vexing bit of censorship (via some alleged bug or other computer "glitch") occurs, it always follows something I have written that threatens media control freaks: those who believe all power has been given unto them or at least who strenuously want others to think that.
Their game is, for one thing, to control the debate in the presidential campaigns. Simple as that.
Most likely suspects: feds operating through one or more cutouts.
Sunday, August 12, 2007
Surely your'e joking, Mr Conant
Draft 3
The Space Shuttle Challenger was destroyed because of an O-ring defect, claimed super-physicist Richard Feynman. Though the shuttle commission didn't agree that the cause was definitely the O-ring, it did concede the possibility and pointed to the joint where that gasket was located as the source of the problem.
The commission also made a brief comment that sabotage was not an issue.
This comes up because I have just read John and Mary Gribbins' account of Feynman's role in the Challenger investigation in their book Richard Feynman, a life in science (Dutton, 1997). The British couple, who have co-written many popular science books, handily pieced together their account from various sources, tossing many accolades toward Feynman for his alertness and brilliance in solving that puzzle, as he had solved so many other puzzles.
But as a journalist somewhat familiar with intelligence and security agency trickery, another possibility jumps off the page: Feynman was being led around by the nose with planted evidence and a craftily helpful general. One cannot be sure whether or not the Nobel laureate was willingly being manipulated. Though a brilliant physicist, at this point Feynmann was suffering the ravages of intestinal cancer and was on his last legs.
Shortly after accepting the call to serve on the panel, Feynman went over to Morton Thiokol where he quickly discovered a report mentioning the O-ring flaw (just like that!). Once in Washington, Feynman was prevented by Chairman William Rogers from doing independent research, but with the help of the NASA chief and the exceptionally helpful general he managed to skirt that proviso, though his preparation barely counts as research.
Feynmann's now famous demonstration of how the O-ring lacked sufficient elasticity when exposed to cold was reported by the Washington Post and New York Times as some sort of breakthrough. Yet, the inquiry was still in its early stages. Whatever happened to Feynmann's vaunted love for the scientific method? Yes, he loved to play the performer. But why perform when the research had only barely begun?
Also, what about the chain of evidence? Can we really be sure that the bit of rubber provided by NASA was the real deal rather than a defective piece in some spook switcheroo? Can you imagine that a security operation wasn't monitoring every move and breath uttered by every commissioner? If you can, you don't know Washington security-politik.
Of course the propaganda value of Feynman's ploy was overwhelming, and the administration no longer had to worry about the political impact from the fears of sabotage that had been current at the time.
Certainly Feynman was terribly ill. But he was alert enough in his reports and public appearances to make it substantially likely that he realized he had done no real science but rather had misled the public and press into thinking a solution had been verified before anyone could possibly be sure.
The commission continued its "work" and eventually issued a report that included an appendix by Feynman. Obviously both the CIA and FBI would have been all over that case long before Reagan suddenly appointed the panel, apparently in response to press reports that NASA employees were in fear of their lives about what they knew. So what was the view of those agencies? The commission seems to have glided over those federal inquiries.
It's quite plausible that the Challenger commission was required to reach a conclusion ordained by the security system. Perhaps security chiefs feared looking bad or -- a darker possibility -- perhaps Soviet moles (remember the Walker spy ring and Aldrich Ames?) were being protected.
Here is one of the reasons sabotage was suspected: Challenger was set to deploy the last satellite needed for activation of a classified three-satellite military communications system. Other satellites intended for this system had been orbited during previous Challenger missions but several had become disabled. News accounts of the time said that a number of military satellite launches had gone awry, though I can now find no reference to that story on the net.
I'm not one of those who think that Gorbachev meant to rein in the KGB. The politburo chose him, I think, because he had the friendly used car-salesman persona more acceptable to the West than did his Oriental potentate predecessors, Brezhnev, Andropov and Chernenko.
Be that as it may. I well recall a news story of the era that reported that NASA had -- before the arrival of congressional investigators -- buried under tons of concrete in deep pits nearly all the physical evidence recovered after laborious undersea operations. You probably won't find that story via Google.
On the day after the disaster (or maybe that night), NASA held a teleconference session with journalists from around the nation. One guy had the audacity to ask whether sabotage was a possibility. His connection went dead and the NASA person acted as though he hadn't heard the question -- which he may not have. That didn't happen to any other questioner, none of whom brought up that already taboo subject.
Yes all this may be so, but why Feynman?
One cannot help but wonder whether a chit was being called in for a youthful indiscretion.
Feynman was a pet of J. Robert Oppenheimer, head of the Manhattan Project. Later, the whiz kid made light of his propensity for breaking into safes, rather than bothering with red tape, in order to provide Oppenheimer with secured documents. Recent scholarship makes a strong case for Oppenheimer having been a crypto-communist before being called to lead A-bomb research.
Though liberal scientists still believe Oppenheimer got a bum rap for what they see as his principled resistance to development of the H-bomb, more jaundiced eyes wonder whether a communist conspiracy was in action to thwart development of the super. (Let it be known: I detest nukes and totally agree with James B. Conant's principled opposition to development of the super, though I see that such a program became inevitable.)
The Venona files tend to indicate that Soviet intrigue in Washington was, if anything, worse than anything Joe McCarthy could have imagined, and also tend to substantiate Whittaker Chambers' general claims, though not all his details. (Do you suppose the NSA is not still holding back much that is in those files?) George Kennan, in his memoir, averred that the communist conspiracy in Washington had, McCarthy notwithstanding, been quite bad.
At the time MIT graduate Feynman went to Los Alamos from Princeton University, communism was the "in thing" among young Jewish intellectuals as well as generally among those youths who considered themselves knowledgeable atheists. Sorry if you don't like that. True anyway. Think of physicist Theodore Hall, who changed his name from Holtzberg to avoid anti-semitic bias. The Harvard whiz kid, who joined the Manhattan Project as an 18-year-old, was identified as a Soviet agent in Venona files released in the 1990s. Before his death, Hall admitted having been a Soviet sympathizer willing to assist Stalin's A-bomb aims.
Then there was Michael Straight, who used his progressive magazine New Republic to thump McCarthy, while concealing the fact that he had been one of those reds in the State Department that McCarthy was targeting. Straight had joined the communists along with Kim Philby and others while students at Cambridge and had gone onto become an NKVD operative in the State Department -- though he served in World War II as a bomber pilot. President Nixon appointed Straight, a scion of the wealthy Whitney family, as a cultural czar at the National Endowment of the Arts, despite his having secretly confessed to having been a communist spy.
Most kids grow out of such conceits. But, once compromised, how does one escape control? An analagous situation would be that of a young drug dealer forced to do dirty work every now and then for the DEA or some other federal agency. Blackmail may easily have been at work in Feynman's case. Not that he is likely to have cared about himself. But his son, just embarking on a career in science, would have been a worry.
Of course, when assessing motives we should take into account Feynman's idiosynchratic character.
The Gribbins recount the ultimate Feynman anecdote:
In 1981, a colleague, Brian Hatfield, happened upon a van decorated with Feynman diagrams that was parked at Caltech. Hatfield noticed the indices on the symbols were down, as in xi rather than up, as in xi. Knowing Feynman's casual disregard for such conventions, Hatfield immediately suspected that Feynman was the van's owner.
Peeking in a window, Hatfield spotted a bale of hay. That clinched it! Had to be Feynman.
[A previous draft of this post misspelled Feynman.]
The Space Shuttle Challenger was destroyed because of an O-ring defect, claimed super-physicist Richard Feynman. Though the shuttle commission didn't agree that the cause was definitely the O-ring, it did concede the possibility and pointed to the joint where that gasket was located as the source of the problem.
The commission also made a brief comment that sabotage was not an issue.
This comes up because I have just read John and Mary Gribbins' account of Feynman's role in the Challenger investigation in their book Richard Feynman, a life in science (Dutton, 1997). The British couple, who have co-written many popular science books, handily pieced together their account from various sources, tossing many accolades toward Feynman for his alertness and brilliance in solving that puzzle, as he had solved so many other puzzles.
But as a journalist somewhat familiar with intelligence and security agency trickery, another possibility jumps off the page: Feynman was being led around by the nose with planted evidence and a craftily helpful general. One cannot be sure whether or not the Nobel laureate was willingly being manipulated. Though a brilliant physicist, at this point Feynmann was suffering the ravages of intestinal cancer and was on his last legs.
Shortly after accepting the call to serve on the panel, Feynman went over to Morton Thiokol where he quickly discovered a report mentioning the O-ring flaw (just like that!). Once in Washington, Feynman was prevented by Chairman William Rogers from doing independent research, but with the help of the NASA chief and the exceptionally helpful general he managed to skirt that proviso, though his preparation barely counts as research.
Feynmann's now famous demonstration of how the O-ring lacked sufficient elasticity when exposed to cold was reported by the Washington Post and New York Times as some sort of breakthrough. Yet, the inquiry was still in its early stages. Whatever happened to Feynmann's vaunted love for the scientific method? Yes, he loved to play the performer. But why perform when the research had only barely begun?
Also, what about the chain of evidence? Can we really be sure that the bit of rubber provided by NASA was the real deal rather than a defective piece in some spook switcheroo? Can you imagine that a security operation wasn't monitoring every move and breath uttered by every commissioner? If you can, you don't know Washington security-politik.
Of course the propaganda value of Feynman's ploy was overwhelming, and the administration no longer had to worry about the political impact from the fears of sabotage that had been current at the time.
Certainly Feynman was terribly ill. But he was alert enough in his reports and public appearances to make it substantially likely that he realized he had done no real science but rather had misled the public and press into thinking a solution had been verified before anyone could possibly be sure.
The commission continued its "work" and eventually issued a report that included an appendix by Feynman. Obviously both the CIA and FBI would have been all over that case long before Reagan suddenly appointed the panel, apparently in response to press reports that NASA employees were in fear of their lives about what they knew. So what was the view of those agencies? The commission seems to have glided over those federal inquiries.
It's quite plausible that the Challenger commission was required to reach a conclusion ordained by the security system. Perhaps security chiefs feared looking bad or -- a darker possibility -- perhaps Soviet moles (remember the Walker spy ring and Aldrich Ames?) were being protected.
Here is one of the reasons sabotage was suspected: Challenger was set to deploy the last satellite needed for activation of a classified three-satellite military communications system. Other satellites intended for this system had been orbited during previous Challenger missions but several had become disabled. News accounts of the time said that a number of military satellite launches had gone awry, though I can now find no reference to that story on the net.
I'm not one of those who think that Gorbachev meant to rein in the KGB. The politburo chose him, I think, because he had the friendly used car-salesman persona more acceptable to the West than did his Oriental potentate predecessors, Brezhnev, Andropov and Chernenko.
Be that as it may. I well recall a news story of the era that reported that NASA had -- before the arrival of congressional investigators -- buried under tons of concrete in deep pits nearly all the physical evidence recovered after laborious undersea operations. You probably won't find that story via Google.
On the day after the disaster (or maybe that night), NASA held a teleconference session with journalists from around the nation. One guy had the audacity to ask whether sabotage was a possibility. His connection went dead and the NASA person acted as though he hadn't heard the question -- which he may not have. That didn't happen to any other questioner, none of whom brought up that already taboo subject.
Yes all this may be so, but why Feynman?
One cannot help but wonder whether a chit was being called in for a youthful indiscretion.
Feynman was a pet of J. Robert Oppenheimer, head of the Manhattan Project. Later, the whiz kid made light of his propensity for breaking into safes, rather than bothering with red tape, in order to provide Oppenheimer with secured documents. Recent scholarship makes a strong case for Oppenheimer having been a crypto-communist before being called to lead A-bomb research.
Though liberal scientists still believe Oppenheimer got a bum rap for what they see as his principled resistance to development of the H-bomb, more jaundiced eyes wonder whether a communist conspiracy was in action to thwart development of the super. (Let it be known: I detest nukes and totally agree with James B. Conant's principled opposition to development of the super, though I see that such a program became inevitable.)
The Venona files tend to indicate that Soviet intrigue in Washington was, if anything, worse than anything Joe McCarthy could have imagined, and also tend to substantiate Whittaker Chambers' general claims, though not all his details. (Do you suppose the NSA is not still holding back much that is in those files?) George Kennan, in his memoir, averred that the communist conspiracy in Washington had, McCarthy notwithstanding, been quite bad.
At the time MIT graduate Feynman went to Los Alamos from Princeton University, communism was the "in thing" among young Jewish intellectuals as well as generally among those youths who considered themselves knowledgeable atheists. Sorry if you don't like that. True anyway. Think of physicist Theodore Hall, who changed his name from Holtzberg to avoid anti-semitic bias. The Harvard whiz kid, who joined the Manhattan Project as an 18-year-old, was identified as a Soviet agent in Venona files released in the 1990s. Before his death, Hall admitted having been a Soviet sympathizer willing to assist Stalin's A-bomb aims.
Then there was Michael Straight, who used his progressive magazine New Republic to thump McCarthy, while concealing the fact that he had been one of those reds in the State Department that McCarthy was targeting. Straight had joined the communists along with Kim Philby and others while students at Cambridge and had gone onto become an NKVD operative in the State Department -- though he served in World War II as a bomber pilot. President Nixon appointed Straight, a scion of the wealthy Whitney family, as a cultural czar at the National Endowment of the Arts, despite his having secretly confessed to having been a communist spy.
Most kids grow out of such conceits. But, once compromised, how does one escape control? An analagous situation would be that of a young drug dealer forced to do dirty work every now and then for the DEA or some other federal agency. Blackmail may easily have been at work in Feynman's case. Not that he is likely to have cared about himself. But his son, just embarking on a career in science, would have been a worry.
Of course, when assessing motives we should take into account Feynman's idiosynchratic character.
The Gribbins recount the ultimate Feynman anecdote:
In 1981, a colleague, Brian Hatfield, happened upon a van decorated with Feynman diagrams that was parked at Caltech. Hatfield noticed the indices on the symbols were down, as in xi rather than up, as in xi. Knowing Feynman's casual disregard for such conventions, Hatfield immediately suspected that Feynman was the van's owner.
Peeking in a window, Hatfield spotted a bale of hay. That clinched it! Had to be Feynman.
[A previous draft of this post misspelled Feynman.]
Saturday, August 11, 2007
Less is more in some vote recounts
The 2004 Florida election debacle is only one of a number of recent races in which the razor-thin result was slimmer than the margin of error.
But a vote-by-vote recount is a somewhat dubious proposition. How could one substantially lower the margin of error in the recount? The more votes that are counted, the greater the likelihood of error.
I recall that media firms hired a polling expert to redo the Florida count. Apparently he took measures to lower the error rate, but I am unsure by how much.
So a thought occurs: Why not simply do a random sample when recounting? There is always a specific number of sample elements that will do for a specific overall number of votes to get the result within a 99 percent (or greater) confidence level.
That sample number is always far lower than the population size. So -- as long as care was taken to assure true randomness in the sample -- one would expect that the error in counting votes in the sample would be much lower than in counting votes in the population. So that error, plus the error implicit in the normal curve, might well be kept lower than the error in a recount. That is, the sample result would, in these special cases, give the winner with more confidence than with a full recount.
Will states, or some election judge, authorize such a procedure in a very tight race? It would be a tough sell politically, since the public is likely to believe that a full recount would be more accurate in exceptionally tight races than a random sample result.
But a vote-by-vote recount is a somewhat dubious proposition. How could one substantially lower the margin of error in the recount? The more votes that are counted, the greater the likelihood of error.
I recall that media firms hired a polling expert to redo the Florida count. Apparently he took measures to lower the error rate, but I am unsure by how much.
So a thought occurs: Why not simply do a random sample when recounting? There is always a specific number of sample elements that will do for a specific overall number of votes to get the result within a 99 percent (or greater) confidence level.
That sample number is always far lower than the population size. So -- as long as care was taken to assure true randomness in the sample -- one would expect that the error in counting votes in the sample would be much lower than in counting votes in the population. So that error, plus the error implicit in the normal curve, might well be kept lower than the error in a recount. That is, the sample result would, in these special cases, give the winner with more confidence than with a full recount.
Will states, or some election judge, authorize such a procedure in a very tight race? It would be a tough sell politically, since the public is likely to believe that a full recount would be more accurate in exceptionally tight races than a random sample result.
Tuesday, August 7, 2007
Most bridges lack dampers
A quick review of relevant Google pages convinces me that the vast majority of highway and train bridges lack dampers for absorbing vibration induced by earthquakes, vehicles, construction activity or other causes. Also, a question arises as to whether bridge repair crews should be required to bring portable dampers to the job site.
A federally financed study found in that computerized "smart dampers" could extend the lives of the nation's decaying highway bridges by many years. But no action seems to have followed that study.
A Taiwanese study pointed out the peril of resonance effects on truss-style train bridges and suggested that dampers would eliminate the dangerous resonance vibrations. Likewise, there is little or nothing on the net about use of such safeguards on U.S. railway bridges.
However, earthquake damage has prompted authorities in California and other quake-prone regions to order the retrofitting of bridges with dampers.
One type of damper is a counterweight that moves opposite the direction of swing and tends to tame the violence of the swinging. This type is found in skyscrapers and would have been in the twin towers, for example. Another type is a viscous or hydraulic damper which works exactly like an automobile shock absorber and is sometimes attached to cables on a suspension bridge or on a stay cable between the deck and the anchorage. (See Friction factor, Bridge Design and Engineering, July 10, 2003, via Google.)
Virtually no cantilever truss bridge -- the type that collapsed in Minnesota -- appears to come with dampers.
When tuned mass dampers are used on bridges, they are generally meant to subdue vibrations of the deck, rather than the structure as a whole, it appears. Of course, such dampers would still tend to curb vibration of the remaining structure if the vibration originated principally on the deck, as presumably occurred in Minnesota.
(For a good glossary of bridge parts, see http://nireland.com/bridgeman/Dictionary.htm )
A federally financed study published in 1999 by a University of Oklahoma team found that computerized "smart dampers" reduced maximum stress on highway bridges by as much as 65 percent in their computer simulation. The authors of the report, W.N. Patten, J. Sun and Annie Zeng, argued that such dampers could extend the lives of America's highway spans by many years, offering an intermediate alternative to the immediate replacement of the many substandard structures.
A Taiwanese study reports that though "steel truss bridges possess the advantages of light weight, high strength and ease of construction," a design problem is that high-speed trains may set off dangerous "multi-resonant peaks" of vibrations. That is, the bridge shakes in tune with its natural frequency, and may collapse.
Jong-Dar Yau, a construction technologist at Tamkang University, said his computerized model showed that tuned mass dampers effectively suppress these resonances during shaking from high-speed trains.
The tuning of a mass damper means to set it to absorb vibrations at specified frequencies. So one consideration might be whether in future construction crews bring mass dampers with them to offset construction vibration.
Regarding the resonance conjecture
I had forgotten the fact that soldiers are often ordered to break cadence when crossing bridges in order to avoid setting off resonance vibrations. We also know that the Millenium Bridge, a footbridge in London, had to be retrofitted with dampers after people walking on the bridge tended to match strides, triggering a resonance wobble.
Bizarre blackout
A spot check shows no further media interest in the matter of vibration or wobble and no interest at all in the matter of the use of dampers in order to safeguard lives. Either the search engines are being jiggered while I use them -- a distinct possibility -- or the word is out to avoid issues prominently mentioned here -- also a distinct possibility.
Aug. 10 2007.Yesterday's N.Y. Times had a story on a conjecture that a truss connector plate was the culprit. The story also acknowledged that some experts viewed jackhammer effects as a potential trigger.
A federally financed study found in that computerized "smart dampers" could extend the lives of the nation's decaying highway bridges by many years. But no action seems to have followed that study.
A Taiwanese study pointed out the peril of resonance effects on truss-style train bridges and suggested that dampers would eliminate the dangerous resonance vibrations. Likewise, there is little or nothing on the net about use of such safeguards on U.S. railway bridges.
However, earthquake damage has prompted authorities in California and other quake-prone regions to order the retrofitting of bridges with dampers.
One type of damper is a counterweight that moves opposite the direction of swing and tends to tame the violence of the swinging. This type is found in skyscrapers and would have been in the twin towers, for example. Another type is a viscous or hydraulic damper which works exactly like an automobile shock absorber and is sometimes attached to cables on a suspension bridge or on a stay cable between the deck and the anchorage. (See Friction factor, Bridge Design and Engineering, July 10, 2003, via Google.)
Virtually no cantilever truss bridge -- the type that collapsed in Minnesota -- appears to come with dampers.
When tuned mass dampers are used on bridges, they are generally meant to subdue vibrations of the deck, rather than the structure as a whole, it appears. Of course, such dampers would still tend to curb vibration of the remaining structure if the vibration originated principally on the deck, as presumably occurred in Minnesota.
(For a good glossary of bridge parts, see http://nireland.com/bridgeman/Dictionary.htm )
A federally financed study published in 1999 by a University of Oklahoma team found that computerized "smart dampers" reduced maximum stress on highway bridges by as much as 65 percent in their computer simulation. The authors of the report, W.N. Patten, J. Sun and Annie Zeng, argued that such dampers could extend the lives of America's highway spans by many years, offering an intermediate alternative to the immediate replacement of the many substandard structures.
A Taiwanese study reports that though "steel truss bridges possess the advantages of light weight, high strength and ease of construction," a design problem is that high-speed trains may set off dangerous "multi-resonant peaks" of vibrations. That is, the bridge shakes in tune with its natural frequency, and may collapse.
Jong-Dar Yau, a construction technologist at Tamkang University, said his computerized model showed that tuned mass dampers effectively suppress these resonances during shaking from high-speed trains.
The tuning of a mass damper means to set it to absorb vibrations at specified frequencies. So one consideration might be whether in future construction crews bring mass dampers with them to offset construction vibration.
Regarding the resonance conjecture
I had forgotten the fact that soldiers are often ordered to break cadence when crossing bridges in order to avoid setting off resonance vibrations. We also know that the Millenium Bridge, a footbridge in London, had to be retrofitted with dampers after people walking on the bridge tended to match strides, triggering a resonance wobble.
Bizarre blackout
A spot check shows no further media interest in the matter of vibration or wobble and no interest at all in the matter of the use of dampers in order to safeguard lives. Either the search engines are being jiggered while I use them -- a distinct possibility -- or the word is out to avoid issues prominently mentioned here -- also a distinct possibility.
Aug. 10 2007.Yesterday's N.Y. Times had a story on a conjecture that a truss connector plate was the culprit. The story also acknowledged that some experts viewed jackhammer effects as a potential trigger.
Monday, August 6, 2007
A shaky situation
Every time a layer of concrete was removed from the I-35W bridge, it would wobble, construction workers have said.
The wobble would be a consequence of load redistribution, no doubt. The removal of the weight might cause the truss system to expand something like a spring. Now if those supports had fatigue cracks, those cracks could have expanded as the support system adjusted to the load change.
If the truss system would shift so noticeably after its load was lightened and shifted, one might expect that mechanical vibration from jackhammers and big pavement pounders would contribute to the weakening of the supports.
BTW, the word wobble appears in yesterday's stories, but not the word vibration.
The wobble would be a consequence of load redistribution, no doubt. The removal of the weight might cause the truss system to expand something like a spring. Now if those supports had fatigue cracks, those cracks could have expanded as the support system adjusted to the load change.
If the truss system would shift so noticeably after its load was lightened and shifted, one might expect that mechanical vibration from jackhammers and big pavement pounders would contribute to the weakening of the supports.
BTW, the word wobble appears in yesterday's stories, but not the word vibration.
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