Feb. 28 update: A week in review: Bertha repair plan, ERP’s 2014 report and a viaduct weekend closure reminder

Posted on Feb 28 2014 2:45 PM

Over the past two weeks, Seattle Tunnel Partners (STP) and Hitachi Zosen, the tunneling machine’s manufacturer, have been developing a plan to fix the seals on the machine. Today, STP notified us that they need to continue to work on the plan and expect to have it ready in the coming weeks. While we are anxious to receive a final plan, this is a complicated fix that requires significant calculation and planning. Their preferred option continues to be excavating a vertical shaft in front of the machine, driving the machine forward into the shaft and then making the needed repairs. At a media briefing this afternoon, Chris Dixon, STP’s project manager, estimated that this work will take six months or more.

On Thursday, the Alaskan Way Viaduct Replacement Program’s Expert Review Panel (ERP) released their 2014 report and recommendations. The Legislature has directed WSDOT to reconvene the panel annually since 2011 to review the program’s finance plan. While we are still reviewing the report, the panel has told us that they have confidence that the project can be successfully built.

This weekend, the Alaskan Way Viaduct will close for its semi-annual inspection. We inspect the viaduct four times a year and two of those inspections require a full closure of the structure. WSDOT bridge crews will close both directions of SR 99 between Denny Way and South Spokane Street from 6 a.m. to 6 p.m. Saturday and Sunday, March 1 and 2. During the inspection, crews will measure existing cracks, look for new ones, check for structural movement and evaluate the integrity of the viaduct’s foundations. Inspection results will be available in mid-March. Crews will also close both directions of SR 99 from Valley Street to the south end of the Battery Street Tunnel from 10 p.m. Friday to 6 a.m. Sunday to shift SR 99 lanes to the east side of SR 99 just north of the Battery Street Tunnel.

There were several reports in the media this week about the viaduct settling due to construction. We’ve done a significant amount of work to reinforce and maintain the viaduct over the years. Immediately after the Nisqually quake, we repaired damaged support columns and expansion joints to make the structure safe and functional. As discussions about how to replace the waterfront section of the viaduct continued, we implemented an automated closure system that consists of traffic gates at all viaduct access points controlled by an earthquake detection system. When the bored tunnel was selected as the preferred option and it was determined it would pass beneath the viaduct, we made strengthening portions of the structure near the tunnel route a requirement of the tunnel contract. STP has since implemented those requirements.

In addition, we have more than a hundred monitors on the structure so that we can watch the structure’s behavior in real time. Safety is our number one priority and we will not let the traveling public use the facility if the structure settles to unacceptable levels.

Previous updates 

Feb. 27, 2014 update - How is an early or late tunnel opening addressed in the design-build contract?

Feb. 25, 2014 update - Ground settlement near the viaduct is safe, expected

Feb. 21, 2014 update – Seattle Tunnel Partners will dig access shaft to reach tunneling machine

Feb. 14, 2014 update – Repair plan to be finalized by the end of February

Feb. 12, 2014 update – Video of Tuesday's news conference