191 tons
Doomed bridge’s weakest areas carried 191 tons: Investigators highlight heavy load piled on Minn. crossing before collapse
Excerpt:
MINNEAPOLIS - More than 191 tons of construction material had been piled over the weakest areas of an interstate bridge that collapsed last August, according to federal investigators.
In a followup to a preliminary report released in January, the National Transportation Safety Board report that the piles of rock and sand were placed over steel plates that were thinner than they should have been.
Calculations by the agency have determined that the bridge in Minneapolis was carrying a 630-ton load at the time it fell into the Mississippi River. About half of that load was sitting on the center span.
The Aug. 1 collapse killed 13 people and injured 145.
The NTSB had previously cited the too-thin gusset plates and construction project weights as factors in the collapse, but Monday's update included drawings and tables that pinpointed the locations of those heavy loads on the structure.
Comment: See earlier CFG post: The straw that broke
Updated: NYTimes: Mounds of Sand Stressed Minnesota Bridge, Report Says
Yes, the bridge may have been carrying a certain weight; my back of the envelope calculation indicates the bridge itself was probably in excess of 5000 tons. A traffic jam would weigh far in excess of 600 tons.
ReplyDeleteAre they truly trying to argue that the bridge's safety factor was close to one--about 1.1 at best? And they allowed it to continue being used? Say what?