Millennium Line - Broadway Extension: Planning & Pre-Construction - Page 390

aberdeen5698 · #**7781** Posted **Mar 29, 2017, 3:27 PM**

Quote:

Originally Posted by Reecemartin

Some on the Eglinton Crosstown are also being mined.

I'm no geotechnical engineer, but I've gotta imagine you need pretty solid ground to do that. Bored tunnels maintain their integrity by installing the concrete rings that line the tunnel as boring machine moves, preventing the overburden from collapsing. It's hard for me to imagine having the same opportunity to do that when mining the cavernous space required for a station.

White Pine · #**7782** Posted **Mar 29, 2017, 4:13 PM**

Apparently Ottawa's bedrock is pretty shallow in most of the downtown area.

Reecemartin · #**7783** Posted **Mar 29, 2017, 9:14 PM**

[Deleted]

jsbertram · #**7784** Posted **Mar 30, 2017, 12:49 AM**

Quote:

Originally Posted by aberdeen5698

I'm no geotechnical engineer, but I've gotta imagine you need pretty solid ground to do that. Bored tunnels maintain their integrity by installing the concrete rings that line the tunnel as boring machine moves, preventing the overburden from collapsing. It's hard for me to imagine having the same opportunity to do that when mining the cavernous space required for a station.

The earth under downtown and False Creek was good enough to run the TBM tunnels from Olympic Stn to Waterfront, so I doubt the earth under Broadway is substantially different to prevent using a TBM for the Broadway tunnels too.

As for mining the stations ... I think that's new for Vancouver.

aberdeen5698 · #**7785** Posted **Mar 30, 2017, 1:28 AM**

Quote:

Originally Posted by jsbertram

The earth under downtown and False Creek was good enough to run the TBM tunnels from Olympic Stn to Waterfront, so I doubt the earth under Broadway is substantially different to prevent using a TBM for the Broadway tunnels too.

As for mining the stations ... I think that's new for Vancouver.

I never said that boring a tunnel is an issue. I said that tunnel boring machines insert concrete rings as they go to prevent tunnel collapse - so they're a lot less prone to issues with unstable ground.

I'm saying that mining a station cavity might be problematic unless the ground is very stable, because you don't have those concrete rings to support the overburden.

Reecemartin · #**7786** Posted **Mar 30, 2017, 2:07 AM**

[Deleted]

VancouverOfTheFuture · #**7787** Posted **Mar 30, 2017, 2:39 AM**

they take core samples to know what is there. if it is determined that mining stations is the route to go THEN IT IS SAFE TO DO SO; otherwise they wouldn't do it. i don't understand this whole thing with a bunch of armchair engineers being all "oh i don't think that would work; that's not going to work; that's not a good idea; how will that work." well, they have the geotechnical report, they are the engineers, and they have enough information and brain power to determine what is safe and doable.

jollyburger · #**7788** Posted **Mar 30, 2017, 3:01 AM**

Quote:

Originally Posted by VancouverOfTheFuture

they take core samples to know what is there. if it is determined that mining stations is the route to go THEN IT IS SAFE TO DO SO; otherwise they wouldn't do it. i don't understand this whole thing with a bunch of armchair engineers being all "oh i don't think that would work; that's not going to work; that's not a good idea; how will that work." well, they have the geotechnical report, they are the engineers, and they have enough information and brain power to determine what is safe and doable.

Isn't that the whole purpose of this forum.. to second guess every architectural, transportation, engineering decision in the city?

aberdeen5698 · #**7789** Posted **Mar 30, 2017, 3:27 PM**

Quote:

Originally Posted by VancouverOfTheFuture

they take core samples to know what is there. if it is determined that mining stations is the route to go THEN IT IS SAFE TO DO SO; otherwise they wouldn't do it. i don't understand this whole thing with a bunch of armchair engineers being all "oh i don't think that would work; that's not going to work; that's not a good idea; how will that work."

I'm not questioning any decisions they make, I'm questioning the armchair engineers that say "hey, why don't they just mine it?". If they decide not to mine it, then they have good reasons for doing so. It may be that they consider it more costly, or it may be that the ground isn't suitable.

My main point is that mining may not be possible for Broadway, even though it's perfectly OK to bore a tunnel through it.

WarrenC12 · #**7790** Posted **Mar 30, 2017, 3:28 PM**

Quote:

Originally Posted by jollyburger

Isn't that the whole purpose of this forum.. to second guess every architectural, transportation, engineering decision in the city?

That and threatening to "start digging ourselves" to get some of these projects going...

jsbertram · #**7791** Posted **Mar 31, 2017, 2:04 AM**

Hey, to the CoV people reading this forum ....

I see the CoV owns the former ScotiaBank at Oak & Broadway, and the building next door (a tailor & a restaurant) is up for sale.

Why not grab this property too and merge them. Now you have a large plot to build new 100' tower (along with a Broadway M-Line entrance). The building can have its own access to the M-Line concourse.

Or lease the large plot to a developer to do the same.

VancouverOfTheFuture · #**7792** Posted **Mar 31, 2017, 4:24 AM**

this line is probably closer to an announcement then we realize. interesting the things the city is doing with this.

Quote:

Originally Posted by jsbertram

That was to get to the 80% engineering complete stage of the project.

This is primarily needed to sharpen the pencils on the cost estimates.

Core samples along the length of the route greatly help to discover what is underground that the TBM will have to dig through - and how expensive that will be.

I've heard the "80% engineering report" is done and being reviewed by everyone involved in the Broadway extension planning

should be interesting to see what the city decides to do about the construction on Broadway and all that traffic being diverted elsewhere.

Ramsay · #**7793** Posted **Mar 31, 2017, 3:26 PM**

Sounds like the Provincial gov is going to match the feds commitment..

B.C. government to match federal funding for Broadway SkyTrain Extension, Surrey LRT

http://www.cbc.ca/news/canada/british-columbia

s211 · #**7794** Posted **Mar 31, 2017, 4:56 PM**

Quote:

Originally Posted by VancouverOfTheFuture

should be interesting to see what the city decides to do about the construction on Broadway and all that traffic being diverted elsewhere.

I seem to recall the city doing SFA about traffic alternates when the Cambie line was undertaken.

SFUVancouver · #**7795** Posted **Mar 31, 2017, 4:57 PM**

Quote:

Originally Posted by Ramsay

Sounds like the Provincial gov is going to match the feds commitment..

B.C. government to match federal funding for Broadway SkyTrain Extension, Surrey LRT

http://www.cbc.ca/news/canada/british-columbia

This is good news, and expected, too, since the NDP has announced their intention to adopt a 40%/Federal matching approach to transit funding.

When the do tender for the SkyTrain Broadway Extension and the Surrey LRT line, I hope that it is a combined RFP so that a single builder is responsible for both. If the folly of the Surrey LRT line is about to be committed to, at least we can realize some cost savings from the efficiencies of running the two projects as a single endeavor.

Jebby · #**7796** Posted **Mar 31, 2017, 6:15 PM**

This is really predictable. I remember saying that it wouldn't surprise me if we got a provincial funding commitment in April/May 2017.

Reecemartin · #**7797** Posted **Mar 31, 2017, 6:58 PM**

[Deleted]

retro_orange · #**7798** Posted **Mar 31, 2017, 8:46 PM**

Quote:

Originally Posted by Jebby

This is really predictable. I remember saying that it wouldn't surprise me if we got a provincial funding commitment in April/May 2017.

I believe most on this forum were saying 'that' while you were still believing that the Canada line was operating at under capacity and stating the Broadway extension is not needed.

Kisai · #**7799** Posted **Mar 31, 2017, 9:27 PM**

Quote:

Originally Posted by Reecemartin

Hmm, seems like it would be more natural to have them as seperate projects, what if there was a funding issue etc, it might mean both get delayed.

They are separate RFP's, therefor they are going to be completely separate projects. That is how this PPP nonsense works.

SFUVancouver · #**7800** Posted **Mar 31, 2017, 11:04 PM**

My logic for having the two projects combined is that the combined dollar value of the project(s) would make it a globally significant RFP and we would likely get more bidders from outside of Canada (and the US), driving down costs and likely attracting parties who do this stuff more often.

There would also be efficiencies to be gained: soft costs on the engineering and architectural side of things; one concrete precast plant; one rail order, etc.