[CDL.TO]

The Big Dig cost almost $24 billion dollars, and was shorter than the Gardner.

I knew someone was going to bring that up.

The Big Dig consisted of a lot more than the Thomas P. O'Neill Jr. Tunnel, the tunnel through central Boston, which is what most people think of when "Big Dig" is mentioned. It also included a 2.6 km tunnel under the harbour, 2 km of mostly tunnelled freeway leading to the new harbour tunnel, realignment of a subway line, reconstruction of two subway stations, building the widest cable-stayed bridge in the world, and realignment and reconstruction of many kms of the roads feeding into the corridor.

It was an absolutely massive project. It basically completely redesigned the road network for all of central Boston in one go. The act of moving the elevated central artery into a tunnel was a minority of the work that was done as part of The Big Dig.

I'm not saying that tunnelling the Gardiner would be cheap. I'm just saying that the $24 billion figure is completely irrelevant to any discussions about what to do in Toronto.

 

[aquateam]

The Big Dig cost almost $24 billion dollars, and was shorter than the Gardner.

Burying highways through downtown sounds like a good idea on paper, but in practice it's astronomically expensive and shows very little value for money. The Big Dig was financed by the Federal government, with money rained down on the city of Boston, and what they got out of it was of very little value. Seattle is experiencing the same thing right now burying their equivalent of the Gardiner. We should learn from other cities' experiences.

If anything is going to be buried through downtown, it should be the DRL. Way more capacity than an underground highway, but at a lower cost. Besides, I thought the main argument for removing the Gardiner was that we were beyond the point of spending hundreds of millions on highway infrastructure? For a large and dense city, geometrical constraints mean that public transit is the only way that people can effectively commute into the core. This article shows that if people commutted into NYC by car instead of by transit, Manhattan would be coated in bridges and surface area equivalent to the entire island would be required for parking. Not that the gardiner is the bottleneck for drivers (the DVP is).

 

[wopchop]

I knew someone was going to bring that up.

The Big Dig consisted of a lot more than the Thomas P. O'Neill Jr. Tunnel, the tunnel through central Boston, which is what most people think of when "Big Dig" is mentioned. It also included a 2.6 km tunnel under the harbour, 2 km of mostly tunnelled freeway leading to the new harbour tunnel, realignment of a subway line, reconstruction of two subway stations, building the widest cable-stayed bridge in the world, and realignment and reconstruction of many kms of the roads feeding into the corridor.

It was an absolutely massive project. It basically completely redesigned the road network for all of central Boston in one go. The act of moving the elevated central artery into a tunnel was a minority of the work that was done as part of The Big Dig.

I'm not saying that tunnelling the Gardiner would be cheap. I'm just saying that the $24 billion figure is completely irrelevant to any discussions about what to do in Toronto.

No doubt, but the article is about replacing 10km of the Gardiner. This would be from the Humber to the Don. Based on the render, looks like they've tunneled under both.

So maybe it doesn't cost $24billion, but I wouldn't doubt it would be astronomical.

EDIT:

Or we can look at the Alaskan Way. A 3.2km tunnel bore (2 lanes each direction) that I believe is supposed to cost around $3billion (the project is bigger, obviously, but includes seawall replacement and removal of the original viaduct). So ... for $3billion you only get a tunnel that is a third the length, with not enough capacity to replace the current Gardiner, and doesn't include any Humber or Don crossings.

 

[rbt]

So maybe it doesn't cost $24billion, but I wouldn't doubt it would be astronomical.

Indeed a very large value. I would expect close to $5B on land expropriation alone to enable cut & cover construction of the highway and ramps through a new corridor; nobody is going to be happy if Lake Shore and Gardiner both disappear completely for several years. I suppose you can go through the lake instead, but that puts massive constraints on construction.

 

[ttk77]

Would the cost of land expropriation for cut-and-cover be less than the additional costs that tunnelling under the existing roads would incur?

 

[rbt]

Would the cost of land expropriation for cut-and-cover be less than the additional costs that tunnelling under the existing roads would incur?

Ramps.

The bulk of the work isn't the nice 6 lane section at a fixed depth as extremely few people use Gardiner as a Toronto bypass. If you take the highway deep enough to go through bedrock and not disturb what's overtop then ramps become significantly longer and more disruptive.

It would be a very long project (decades) most likely rebuilding both the existing Gardiner and LakeShore in the process to get them out of the way.

 

[ttk77]

Thanks. Just trying to get my head around what was being presented in the article. Not actually advocating something like this.

 

[howl]

Ramps.

The bulk of the work isn't the nice 6 lane section at a fixed depth as extremely few people use Gardiner as a Toronto bypass. If you take the highway deep enough to go through bedrock and not disturb what's overtop then ramps become significantly longer and more disruptive.

It would be a very long project (decades) most likely rebuilding both the existing Gardiner and LakeShore in the process to get them out of the way.

I think if you had four lanes in a cut trench for through-traffic and four lanes covering it on top for local traffic then you could use two additional lanes as ramps between the two levels (essentially another lane that goes up and down - probably in the middle). It's basically the European service road model with the service lanes over the express lanes rather than beside them. It would be the equivalent of a ten lane boulevard with no traffic lights for four of the lanes.

Sort of like the Parramatta Road section of this proposed highway in Sydney Australia: http://www.tunneltalk.com/Australia...-West-Connex-project-towards-design-phase.php
http://www.tunneltalk.com/images/sydney-metro/3-West-Connex.jpg

 

[rbt]

I think if you had four lanes in a cut trench...

I assume the reason everyone likes the tunnel idea is they think it can be built without disrupting traffic.

An open-cut trench in the current Gardiner corridor, while a good final result, would be tricky to build with little disruption. You may be able to get away with only closing half of Lake Shore at a time and every North/South intersecting street twice (bridge north bit then south bit later). That'll still make it a 15 year project and assumes nothing on Gardiner like vertical support columns need to be relocated.

 

[ssiguy2]

I don't agree with a tunnel unless they can put the ST trains in the tunnel.

I do not think land would be of any cost because they would have to buy the land but then conversely would be able to see the land that the current Gardiner is on which is probably more valuable due to much being right up against the water.

 

[wopchop]

I don't agree with a tunnel unless they can put the ST trains in the tunnel.

I do not think land would be of any cost because they would have to buy the land but then conversely would be able to see the land that the current Gardiner is on which is probably more valuable due to much being right up against the water.

Sure it would be. A tunnel will require more land for the ramps, due to the depth. You will also need emergency exits, ventilation shafts, etc.

 

[CapitalSeven]

I would think of a tunnel or trench section as a bypass through the East Bayfront, from east of Cherry to Church or so. If you don't need to access anything in that zone, you go in then out of it. No exit ramps, just a dip down and then up again.

 

[howl]

I would think of a tunnel or trench section as a bypass through the East Bayfront, from east of Cherry to Church or so. If you don't need to access anything in that zone, you go in then out of it. No exit ramps, just a dip down and then up again.

That's true. If the idea is to move cars and trucks as efficiently as possible from Lakeshore and Yonge area to the bottom of the DVP then you wouldn't need any ramps, except for at the end.

As for the 'disruption' argument, there is going to be disruption no matter what you do. Even the 'maintain' option requires major work to be done on the existing structure which will require extensive closures of both the Gardiner and the Lakeshore, not just now, but again in other 30 years and then again 30 years after that.

 

[ttk77]

So it looks like more people support tearing down this section of road than support rebuilding it (45% vs 33%, across all demographic lines and city locations). I hope council will have some courage come next week.

 

[CDL.TO]

Tory's Director of Communications, Amanda Galbraith, has complained on Twitter that the poll is invalid because it failed to utilize the term "hybrid". She stated:

"unfortunately poll doesn't use name Hybrid, so how does it accurately present options? Debate but shld reflect actual choices"

The actual poll question was:

"And thinking of the plan to tear down the Gardiner east of Jarvis and replace it with a boulevard and the plan to mostly rebuild the Gardiner east of Jarvis as it is now, which do you prefer?"

Seems to me that it actually reflects the choices.

I think her response really proves the point that I made earlier that the term "hybrid" was specifically chosen to convey a sense of compromise and reasonableness which people are naturally inclined towards. When you describe the options without using that very important word, support declines.

Here are the expanded poll results: http://www.mainstreettechnologies.ca/45-support-tearing-down-gardiner-east/