Transportation Nation (WNYC.ORG): Bridges In Washington Suffer Repeated Hits (http://www.wnyc.org/blogs/transportation-nation/2013/jul/16/bridges-washington-suffer-repeated-hits/)
QuoteThere are more than 200 bridges in Washington that could collapse if a key part fails. They're classified as being fracture-critical, just like the Interstate 5 span that plummeted into the Skagit River in May after it was hit by an oversized load. Out of those fracture-critical bridges, at least three others have been struck multiple times in the past five years. Experts say repeated bridge strikes can potentially cause catastrophic problems.
QuoteThe three fracture-critical bridges in the state that have been hit more than once are a US Highway 101 bridge, a state Route 4 bridge over the Elochoman River, and the Kummer Bridge along state Route 169.
Washington tends to have a pretty bad reputation with its bridges. Oregon is pretty bad too. *cough*Sellwood*cough*
I remember that a semi hit one of the overpasses on SR-14 in Vancouver, but it's a pretty modern structure. I think they had to replace the signs on it.