I have previously posted in other threads that a new replacement for the GMT would be in the 2025 - 2030 time frame. Still makes sense.
Clark said that a new replacement would be at least 10 years out. In that vein, we would be looking at 2022 - 2023 at the earliest. But that could have also been the project definition report ("PDR") release within that time frame. Remember that the PDR for the Hwy 1/PMB was not released until 2006, then public consultation, then environmental assessment/ certification, then construction.
All told, from commencement, the Hwy 1/PMB upgrades will have taken 6 - 7 years until final completion.
A September, 2009 article from the Journal of Commerce stated:
Massey Tunnel seismically upgraded to today’s standards
The Deas Island tunnel was designed in the 1950s when seismic stability played a lesser part in the design process.
Awareness of the effects of serious seismic activity has increased dramatically since construction was completed in 1959.
The river bed is a 600 metre thick layer of sediment on top of bedrock.
This sedimentary layer could liquefy during a major earthquake, causing serious damage to the tunnel.
Buckland & Taylor Ltd. was retained in 1999 to prepare a seismic assessment of the structure, which identified seismic vulnerabilities and established feasible seismic retrofits and costs.
A retrofit project was then initiated to increase the survivability of the tunnel in the event of a significant earthquake.
In May 2001, Buckland & Taylor Ltd. was selected to prepare the final design for the seismic retrofits.
Subsequently, the B.C. Ministry of Transportation upgraded the pumping and emergency power system and Buckland & Taylor Ltd. performed this work. The retrofits were completed in 2006.
Upon completion, the ministry decided not to proceed with the other improvements. A second value engineering exercise took into consideration that there is a plan to replace the tunnel with a new crossing in the next 20 years.
So a completion date would be ~2029 in that regard. Again, makes sense. Again, we would be looking at a PDR in the ~2023 - 2025 time frame.
The Greater Vancouver Gateway Council ("GVGC") utilized Delcan Engineering for a July, 2003 analysis of contemplated upgrades to Hwy 99/ GMT. Back then, a new 2-lane immersed tube upstream was proposed for a 3 + 1 HOV flow in each direction at peak hours. IOW, an 8-lane crossing (in terms of counterflow at peak) 10 years ago.
The PDR won't likely be produced for another 10+ years and it will also need to look at longer term future traffic flows. That's why I'm convinced that a 2+3+3+2 c/d cable-stayed bridge will also be its replacement. BC MoT has now learnt something from it's initial dabbling in a c/d for the new PMB. The new major river crossing template, so to speak.
And I still think that the existing GMT could be utilized for a future lrt line.
The GVGC report also includes an expansion of the Oak St. Bridge to 6 lanes. I suspect that an entirely new structure will replace the OSB as part of the new "system-wide" upgrades for Hwy 99/GMT down the road.