The state and the city have been pushing the tunnel at a cost of $4.5 billion and the rebuild at $3.5 billion and have tried to ignore everything else.

Recall that the viaduct is some 2.2 miles long, south of the Battery Street tunnel consisting of some 64 three-span structural units. But only two units were damaged during the Nisqually earthquake of Feb. 28, 2001 and those were repaired and the viaduct reopened to traffic.

The project now includes the lowering of Aurora and adding new bridges across Aurora. The project now also includes all of the 8,000-foot long seawall even though only 3,000 feet parallels the viaduct. Even that part of the seawall is far enough away to allow the allow the soils under the viaduct to be stabilized independent of the seawall. We wonder if that is the best use of State Department of Transportation funds to pay for these added items.

Our proposed retrofit also allows work on the viaduct to be done while traffic is maintained, preserves waterfront businesses, saves the cost of any demolition estimated to be $150 million, maintains existing ferry traffic and allows the continued use of the viaduct at a savings of some $140 million each year for vehicular traffic. Further the retrofitted viaduct will withstand the predicted 500-year earthquake without damage and also the 2,500-year quake with damage and a shut down.

The retrofit installs bracing and dampers on the lower level only, together with cement grouting of the foundation soils. The cost of this work is estimated to be $311 million for the viaduct only. We do allow for a contingency of $300 million and also another $200 million for the seawall work should that need to be included. That savings compared to the tunnel allows for $3 billion to be used for other needed transportation projects.

To confirm our findings, we retained the engineering firm of Miyamoto International to do a separate analysis and report. We forwarded that study to the state for review. They, in turn, retained another firm to review our proposals. No surprise that firm working for the state found all kinds of reasons why our retrofit would not work. We always thought that engineers should solve problems, not just talk about them.

The differences between our analysis and the state's involves several items. First the state says that our cement grouting will not work under the viaduct yet they propose to use it behind the seawall. The state says that the retrofitted viaduct will not with stand the 2,500-year earthquake. As a matter of fact most of our downtown structures would fail. Again even the 2,500-year quake is not realistic as even the evidenced by the recommendations of the American Association of State Highway and Transportation Officials, the national manual for bridge design. Their criteria would specify the 500-year quake level as being appropriate in this case.

The state wants to provide for heavier truck loadings, as well as wider shoulders. Those are desirable items but hardly worth the costs as the existing viaduct has handled the traffic for the last five years and is expected to do so for many more years if maintained.

The retrofit work could start in the near future and could be done in a few short years compared to the eight or 10 years for the tunnel or rebuild.

The retrofit is a reasonable answer at a great savings in cost and should be properly considered by the state and city

Victor O. Gray

Civil and Structural Engineer

Viaduct Preservation Group