Retrofit a cost-effective answer
The debate over what to do with the Alaskan Way Viaduct has taken a new turn. Now, the surface/transit alternative is being pushed...
Special to The Times
The debate over what to do with the Alaskan Way Viaduct has taken a new turn. Now, the surface/transit alternative is being pushed as a viable option, assuming that a no-no vote is the voters' choice on March 13. Even with a no-yes vote, the new elevated viaduct would be opposed by the city of Seattle and possibly delayed so as to make the surface/transit option again the choice. Should not the retrofit of the current viaduct also be considered as an alternative?
The proposed retrofit of the viaduct has been on the table for more than two years. It should be recalled that during the 2001 Nisqually earthquake, only two structural units out of the 64 that make up the 2.2-mile-long viaduct were damaged. Those were repaired immediately and the viaduct was returned to service.
The existing structure can remain in service for many years if properlyretrofitted by bracing and foundation work. We estimate the cost of theretrofit at $1.2 billion.
The Washington State Department of Transportation rejected the retrofit as a possible solution, claiming it would cost some $2.3 billion, or about 80 percent of the cost of the proposed rebuild's $2.8 billion. WSDOT also claimed that the retrofit would last only about 25 years.
How the department could ignore even a $500 million savings, and without a thorough investigation of thelifespan of a retrofit, remains a good question.
The $2.3 billion cost figure was carried in a WSDOT release in December without any detailed backup. We asked for backup data and on Dec. 20 received only incomplete data. With this limited information, we were still able to show that the costs could be substantially reduced. The state again ignored our analysis.
WSDOT has long ignored any retrofit. In a Nov. 13 report, T.Y. Lin, the transportation department consultant, agreed that the viaduct could be retrofitted along the lines that our group suggested. But, again, the Department of Transportation has elected to ignore any retrofit.
The retrofit can last for at least 50 years if maintained. Consider the ages of many Seattle bridges that have been retrofitted and are still in heavy use: the Montlake Bridge, 1917; the University Bridge, 1919; the Fremont Bridge, 1917; the Ballard Bridge, 1917; the Aurora Bridge, 1932; the Spokane Street Viaduct, 1930. The estimated 25-year lifespan of an Alaskan Way Viaduct retrofit is more misinformation by WSDOT.
One major issue the state and the city seem to ignore is that a new elevated structure or tunnel would shut down or disrupt watefront traffic for years. That traffic disruption would clog all adjacent streets and severely impact waterfront businesses. The financial impact is expected to be more than $2 billion each year of closure, according to Hebert Research.
The state estimates that a four-lane tunnel would take about seven years, while the rebuild would take 10 years. By comparison, the retrofit can be started in a short period of time and can be completed in about three years. The viaduct can be kept open to traffic during the retrofit.
The retrofit provides a reasonable, cost-effective solution to the viaduct problem and should be adopted.
Victor O. Gray is a retired structural engineer and member of the Viaduct Preservation Group. He, along with the late Neil H. Twelker, began suggesting the retrofit approach as early as 2001.