December 30, 2002
The Quakeproof Bridge
After nine months of work, the Burnside Bridge has become the "first and only one of Multnomah County's six Willamette River bridges to be strengthened against damage" should a major earthquake strike the Portland area:
"It is one of the critical pieces of infrastructure as an emergency transportation route," said Doug McGillivray, county Emergency Management director.
The bridge is part of the county's lifeline corridor if people must evacuate the central area. It is the midpoint of Portland, connecting north and south, east and west. West Burnside Street stretches from the bridge to Washington County. East Burnside Street/Sandy Boulevard stretches to east Multnomah County.
For what it's worth, according to the Portland Timeline, a civil defense test evacuation in September of 1955 found it "took 19 minutes to evacuate the downtown core." At the time, the population of Portland as a whole was somewhere around 375,000 people, although I have no idea how many were involved in the test evacuation of the city core.