In the fall of 2009, two major U.S.
bridges were closed. The San Francisco–
Oakland Bay Bridge was closed for a
weekwhenabeamcamecrashingdown
on the lower roadway. The beam was
part of an emergency repair of the eastern
part of the bridge, connecting Oakland
to Yerba Buena Island. The eastern
section includes a large cantilever truss
spanandisbelievedtobevulnerabletoa
large earthquake. Part of the span, in
fact, failed in during the Loma Prieta
Earthquake of 1989; an approach span
of the upper roadway collapsed onto the
lowerdeck,resultinginlossoflif