Here in Seattle they just tore down a 13-story skyscraper. It was built about 10 years ago. They started having corrosion in the pre-tensioned wires. They were supposed to have a dab of epoxy on the ends. The guy didn’t do his job. And managers, inspectors, etc. didn’t do their jobs. They spent millions trying to fix the problem to no avail.
Funny thing is, it was built by the carpenter’s union FOR the carpenter’s union. To be a source of income for their pensions.
I’m guessing it will be a tad more expensive to tear down the bridge and start from scratch.
“....Replacement of the rods, which are embedded in the foundation, would be difficult if not impossible. “My concern with the (tower) anchor rods is that there’s no redundancy,” Chung said. “Once they break, there’s nothing you can do.”
Chung and Thomas also identified unexplained hardness profiles in many rods, including those at the main cable eastern anchorage and those anchoring the tower. Contrary to normal expectations, some of the rods are harder internally than at their edges....”
I’m feeling a bit of schadenfreude for the carpenters union there.
http://www.seattlepi.com/local/article/High-rise-unsafe-hundreds-uprooted-884077.php
In Boston's Big Dig, a tunnel panel came down and crushed a lady in a car. Apparently epoxy was used to hold them up. A friend's dad who had extensive experience in that area said that there were probably two issues--first, the strength of the epoxy was mixture-sensitive, but second (and probably more importantly) the joint had to be completely clean before the cement was applied--no residual concrete dust. Wouldn't you suspect worker sloppiness in this area? A lot of time and money was spent inspecting the remaining panels, and there were a lot of poor joints.
Another 7.0 like the Loma Prieta quake will make quick work of the destruction. Just pray you're not on the span when it ends up on the bottom of the bay.