Bay Bridge fasteners withstand testsDon't Miss:Best pot for depressionSaunders: Retrofit needs a retrofitGarchik: Soothing a politicianTasty Quinto SolInstagramming Burning ManThe construction continues on the eastern section of the Bay Bridge as seen from Treasure Island, in San Francisco, Calif., on Tuesday August 13, 2013. After years of delays, cost increases and complications on the $6.3 billion Bay Bridge project, finally there's some good news. The new east span will open to drivers traveling in both directions by the end of 2013 instead of the earlier plan to make eastbound motorists wait until 2014.Photo: Michael Macor, San Francisco ChronicleThe construction continues on the eastern section of the Bay Bridge.Tests that Caltrans launched to predict the reliability of hundreds of atrisk steel fasteners on the new Bay Bridge eastern span after 32 rods failed this year are giving rise to cautious optimism that the parts will not need to be replaced, agency engineers say."I'm pleased with what I'm seeing so far," , Caltrans' chief engineer for the span, said after seeing early results of tests intended to gauge the steel parts' ability to hold up in a marine environment."These tests are going really well," Maroney said. "While it's too early to draw conclusions, so far it's good news."The tests, which started this month, were ordered by Caltrans after the 32 rods installed on seismicstabilizing bridge structures in 2008 snapped when workers tightened them in March. It turned out that the rods' hardened, galvanized steel had been contaminated by crackinducing hydrogen, Fred Jackson Jersey either during manufacturing or from being left in holes that filled up with rainwater.The mass cracking threatened to delay the span's Sept. 3 opening. Caltrans eventually found a quick fix that passed muster with federal highway officials, but that left unanswered the question of what to do about 2,200 similar steel bolts and rods on the $6.4 billion span.Galvanized steelAll the fasteners are made of a grade of galvanized steel that Caltrans prohibited in bridge construction because of its vulnerability to cracking. Caltrans decided that such bolts, specially processed to avoid hydrogen contamination, could work on the Bay Bridge a conclusion that some outside experts have since criticized as faulty.Of the 2,200 rods and bolts at issue, more than 400 anchor the eastern span's tower and cannot be reached for replacement. Caltrans hopes to keep many of those and more than 1,100 other steel fasteners dry and at a low tension, reducing their risk of being contaminated by hydrogen and cracking.That leaves 700plus rods and bolts thought to be at greatest risk of cracking because they are extrahard, under high tension and exposed to the moist, hydrogenrich air. Caltrans has indicated it might replace them, pending the outcome of tests to determine whether that is necessary.Saltwater dunksSome of the tests involve dunking samples of the rods in saltwater tanks designed to mimic a decade http://www.billsofficialnflstore.com/Black+Fred+Jackson+Jersey of weather conditions and slowly pulling them apart to simulate their susceptibility to environmental forces.Caltrans has not provided any specifics as to the cost of the testing effort or who will pay for it. Each 23day test involves using 300ton hydraulic jacks to subject the samples to steadily greater stress.As http://www.billsofficialnflstore.com of Friday, Caltrans said, three of the four samples being tested had been stretched to loads at least as great as they will be subjected to on the bridge, without breaking. The tests will continue until the rods snap, to predict how much stress they can take."So far, not only in this test, but in other tests," Maroney said, the rods "have not shown the poor properties we saw" in the steel fasteners that broke Fred Jackson Jersey Ebay in March.Other tests include hitting the metal with mechanical hammers to test the steel's toughness, as well as examining its metallurgical structure for signs it could be susceptible to becoming brittle."It takes times to do these tests," Maroney said, but "if we get good, strong extra evidence that says the (rods and bolts) are not sensitive to that kind of stress in the environment," chances are they will be left in place on the new bridge.Caltrans doesn't "want to spend a penny of taxpayer money on replacing a rod if there is not a need to do it," Maroney said.Caltrans' tests questionedSome outside experts, however, questioned whether the Caltrans tests would accurately predict how the rods and bolts will hold up on the bridge."It's really hard and requires of lot of thought and luck to recreate the field situation in a laboratory I have spent 30 years doing it," said , a hydrogenassisted cracking and corrosion expert in Texas."Sometimes you can't get it to fail, no matter what you do," Kane said. "You have to know all the variables. In complex, engineered structures, it's impossible to know all the variables."The topic the articlehttp://www.friendster.dk/index.php?do=/public/blog/view/id_177010/title_an-can-play-the/http://www.halfproshop.com/index.php?option=com_blog&view=comments&pid=191770&Itemid=182http://www.desempregados.net/activity/p/36294/
really hard and requires
Bay Bridge fasteners withstand testsDon't Miss:Best pot for depressionSaunders: Retrofit needs a retrofitGarchik: Soothing a politicianTasty Quinto SolInstagramming Burning ManThe construction continues on the eastern section of the Bay Bridge as seen from Treasure Island, in San Francisco, Calif., on Tuesday August 13, 2013. After years of delays, cost increases and complications on the $6.3 billion Bay Bridge project, finally there's some good news. The new east span will open to drivers traveling in both directions by the end of 2013 instead of the earlier plan to make eastbound motorists wait until 2014.Photo: Michael Macor, San Francisco ChronicleThe construction continues on the eastern section of the Bay Bridge.Tests that Caltrans launched to predict the reliability of hundreds of atrisk steel fasteners on the new Bay Bridge eastern span after 32 rods failed this year are giving rise to cautious optimism that the parts will not need to be replaced, agency engineers say."I'm pleased with what I'm seeing so far," , Caltrans' chief engineer for the span, said after seeing early results of tests intended to gauge the steel parts' ability to hold up in a marine environment."These tests are going really well," Maroney said. "While it's too early to draw conclusions, so far it's good news."The tests, which started this month, were ordered by Caltrans after the 32 rods installed on seismicstabilizing bridge structures in 2008 snapped when workers tightened them in March. It turned out that the rods' hardened, galvanized steel had been contaminated by crackinducing hydrogen, Fred Jackson Jersey either during manufacturing or from being left in holes that filled up with rainwater.The mass cracking threatened to delay the span's Sept. 3 opening. Caltrans eventually found a quick fix that passed muster with federal highway officials, but that left unanswered the question of what to do about 2,200 similar steel bolts and rods on the $6.4 billion span.Galvanized steelAll the fasteners are made of a grade of galvanized steel that Caltrans prohibited in bridge construction because of its vulnerability to cracking. Caltrans decided that such bolts, specially processed to avoid hydrogen contamination, could work on the Bay Bridge a conclusion that some outside experts have since criticized as faulty.Of the 2,200 rods and bolts at issue, more than 400 anchor the eastern span's tower and cannot be reached for replacement. Caltrans hopes to keep many of those and more than 1,100 other steel fasteners dry and at a low tension, reducing their risk of being contaminated by hydrogen and cracking.That leaves 700plus rods and bolts thought to be at greatest risk of cracking because they are extrahard, under high tension and exposed to the moist, hydrogenrich air. Caltrans has indicated it might replace them, pending the outcome of tests to determine whether that is necessary.Saltwater dunksSome of the tests involve dunking samples of the rods in saltwater tanks designed to mimic a decade http://www.billsofficialnflstore.com/Black+Fred+Jackson+Jersey of weather conditions and slowly pulling them apart to simulate their susceptibility to environmental forces.Caltrans has not provided any specifics as to the cost of the testing effort or who will pay for it. Each 23day test involves using 300ton hydraulic jacks to subject the samples to steadily greater stress.As http://www.billsofficialnflstore.com of Friday, Caltrans said, three of the four samples being tested had been stretched to loads at least as great as they will be subjected to on the bridge, without breaking. The tests will continue until the rods snap, to predict how much stress they can take."So far, not only in this test, but in other tests," Maroney said, the rods "have not shown the poor properties we saw" in the steel fasteners that broke Fred Jackson Jersey Ebay in March.Other tests include hitting the metal with mechanical hammers to test the steel's toughness, as well as examining its metallurgical structure for signs it could be susceptible to becoming brittle."It takes times to do these tests," Maroney said, but "if we get good, strong extra evidence that says the (rods and bolts) are not sensitive to that kind of stress in the environment," chances are they will be left in place on the new bridge.Caltrans doesn't "want to spend a penny of taxpayer money on replacing a rod if there is not a need to do it," Maroney said.Caltrans' tests questionedSome outside experts, however, questioned whether the Caltrans tests would accurately predict how the rods and bolts will hold up on the bridge."It's really hard and requires of lot of thought and luck to recreate the field situation in a laboratory I have spent 30 years doing it," said , a hydrogenassisted cracking and corrosion expert in Texas."Sometimes you can't get it to fail, no matter what you do," Kane said. "You have to know all the variables. In complex, engineered structures, it's impossible to know all the variables."The topic the articlehttp://www.friendster.dk/index.php?do=/public/blog/view/id_177010/title_an-can-play-the/http://www.halfproshop.com/index.php?option=com_blog&view=comments&pid=191770&Itemid=182http://www.desempregados.net/activity/p/36294/