This forum post is hidden because you have chosen to ignore WernerS2. Show Details
This forum post is hidden because you have submitted an abuse report against it. Show Details
CBS/AP/ May 25, 2013, 5:33 PM
Thousands of U.S. bridges vulnerable to collapse
Thousands of bridges around the U.S. may be one freak accident or mistake away from collapse, even if the spans are deemed structurally sound.
The crossings are kept standing by engineering design, not supported with brute strength or redundant protections like their more modern counterparts. Bridge regulators call the more risky spans "fracture critical," meaning that if a single, vital component of the bridge is compromised, it can crumple.
Those vulnerable crossing carry millions of drivers every day. In Boston, a six-lane highway 1A near Logan airport includes a "fracture critical" bridge over Bennington Street. In northern Chicago, an I-90 pass that goes over Ashland Avenue is in the same category. An I-880 bridge over 5th Avenue in Oakland, Calif., is also on the list.
(continues at above URL)