Other info about #bridges like the one that collapsed in #Pittsburgh: the particular #bridge type (steel girder or frame), has actually declined in use 14% for #highwaybridges since 1992 (173k to 148k). #BridgeCollapse #infrastructure @USDOTFHWA@twitter.com @ASCETweets@twitter.com @USDOT@twitter.com @ASCE_SEI@twitter.com