Date:
Tuesday, December 05, 2006
Contact:
Amy Grotefendt, Alaskan Way Viaduct and Seawall Replacement Project, (206) 267-3789, cell (206) 295-9846
Kristy Laing, Alaskan Way Viaduct and Seawall Replacement Project, (206) 382-6361, media cell (206) 437-5061
SEATTLE – Retrofitting the Alaskan Way Viaduct to a reasonable standard of seismic safety would cost $2.3 billion, almost as much as a brand new elevated structure and without bringing the added benefits or overall lifespan of a new facility. WSDOT concluded that replacing the viaduct is the most responsible investment of taxpayer dollars.
An independent internationally-recognized engineering firm, T.Y. Lin International, has developed the approach to a retrofit that would be necessary to adequately protect the existing viaduct to accepted standards of seismic risk. For an earthquake of serious severity likely to have a one in 10 chance of occurring in the next 50 years, the standard would require that the viaduct, though it might be damaged, would still be usable after repairs. T.Y. Lin’s report outlines what would be necessary to meet this standard, including new bracing and other improvements, and also strengthening the footings and piers located in the weak and earthquake vulnerable soil on which the viaduct rests.
T.Y. Lin also developed a plan for the improvement to meet the standard for an even more severe earthquake that would be expected to have a one in 50 chance of occurring in the next 50 years. The applicable standard stipulates that a structure like the viaduct would not collapse in this type of earthquake even though it might suffer serious damage that would require major repair or even full replacement.
Using T.Y. Lin’s work, WSDOT estimates that retrofitting the structure to these standards would cost $2.3 billion.
A retrofitted viaduct would have an anticipated life span of 25 years, while a new structure will last 75 to 100 years. While a retrofitted structure helps with seismic improvements, the seawall replacement would still require construction disruption along the waterfront and the retrofitted structure would not have the safety improvements such as wider lanes and shoulders. The traffic disruptions during construction of a retrofit will likely be significantly longer than suggested by the Viaduct Preservation Group.
David Goodyear, T.Y. Lin’s principal investigator, said, “We learned from previous work that the viaduct today comes nowhere close to meeting current earthquake standards, and Victor Gray’s retrofit proposals do not make enough difference to close the gap.”
“Based on T.Y. Lin’s work, we have developed a cost estimate that accounts for design costs, future inflation, and necessary strengthening of the structure” commented Ron Paananan, Alaskan Way Viaduct and Seawall Replacement Project Director. “With a retrofit, we could buy, at a very high price, some additional measure of protection. Unfortunately, we get little or nothing else from the investment, such as the overall life span of the new structure, and safer, more efficient traffic management for everyday drivers. We think the report makes the case stronger than ever: that replacing the viaduct is the responsible investment of taxpayer money.”
More information about the Alaskan Way Viaduct and Seawall Replacement Project is available at www.wsdot.wa.gov/projects/viaduct.
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