Broadway Subway - Millennium Line Extension to Arbutus | U/C

[jollyburger]

Originally Posted by s211

Apologies if I'm unclear. It was my uneducated understanding that the deck is necessary to keep the road open while constructing stations underneath. I'd perhaps mistakenly surmised that the heights of the deck would be significant in order to permit street level access underneath, i.e. allow workers space under the deck to work while the road is deconstructed and to provide excavation access.

Perhaps the engineering is different than I'd assumed.

This photo might do a better job of explaining things.

[cganuelas1995]

Originally Posted by jollyburger

This photo might do a better job of explaining things.

That's like some minecraft stuff right there.

[Migrant_Coconut]

You can clearly see workers under the deck at the bottom-left. All they need to do is keep digging.

[aberdeen5698]

Originally Posted by Migrant_Coconut

You can clearly see workers under the deck at the bottom-left. All they need to do is keep digging.

I think the question is that in "Step 4" it doesn't look like there's enough space between the bottom of the excavation and the road deck to fit an excavator in there.

And I guess the unspoken assumption is that there's access to the excavation from a property beside it below road level in order to haul out the spoils...

[madog222]

Originally Posted by aberdeen5698

I think the question is that in "Step 4" it doesn't look like there's enough space between the bottom of the excavation and the road deck to fit an excavator in there.

And I guess the unspoken assumption is that there's access to the excavation from a property beside it below road level in order to haul out the spoils...

Yeah, access to bellow the deck will be from the worksite where the station house will be.

[Jimbo604]

Originally Posted by aberdeen5698

I think the question is that in "Step 4" it doesn't look like there's enough space between the bottom of the excavation and the road deck to fit an excavator in there.

And I guess the unspoken assumption is that there's access to the excavation from a property beside it below road level in order to haul out the spoils...

I think it is "makes for a nice diagram for people to look at" scale rather than everything to actual scale.

Also, is anyone else disappointed with the amount of surface disruption for a bored-tunnel approach? Originally I was thinking/hoping they could use the large properties they have lined up beside each station (Main/Cambie/Oak/Granville/Arbutus) for their station excavation, building etc.

[s211]

Thanks for the graphic. That helps a lot. I did not realize they were digging down before putting the deck on.

[Aroundtheworld]

Originally Posted by Jimbo604

I think it is "makes for a nice diagram for people to look at" scale rather than everything to actual scale.

Also, is anyone else disappointed with the amount of surface disruption for a bored-tunnel approach? Originally I was thinking/hoping they could use the large properties they have lined up beside each station (Main/Cambie/Oak/Granville/Arbutus) for their station excavation, building etc.

Along these lines, I would like to see Translink to look at Barcelona's approach for future tunnel bore projects. This video by RM Transit does a good job explaining it.

• Video Link

Basically, the way it works is:

• One 10m tunnel is excavated. Directions are stacked on top of each other.
• Since the tunnel is so wide, you don't need to dig station boxes, just elevator access
• The width also allows for switches to be easily built between track directions and flyovers for possible branches

The cost of Spanish metro projects is impressively low, about 2 or 3x less than an equivalent NA project. (And Spain is a developed country).

[Changing City]

Originally Posted by s211

Thanks for the graphic. That helps a lot. I did not realize they were digging down before putting the deck on.

They've started digging the trench for the north side deck for Cambie station too. At Main they'll now be digging a trench on the south side of the street, and putting another deck for that side, and then the normal street width should be available while they continue to excavate deeper underneath, and off to the south side where the station house will be.

[WarrenC12]

Originally Posted by Jimbo604

Also, is anyone else disappointed with the amount of surface disruption for a bored-tunnel approach? Originally I was thinking/hoping they could use the large properties they have lined up beside each station (Main/Cambie/Oak/Granville/Arbutus) for their station excavation, building etc.

Yeah that is what I've been commenting on since this all started. It's a lot of disruption and it's already behind schedule. Comparing timelines and costs to Cut and Cover might be interesting when all is said and done.

Unfortunately after the Canada Line, those are cursed words in Vancouver.

[twoNeurons]

Originally Posted by WarrenC12

Yeah that is what I've been commenting on since this all started. It's a lot of disruption and it's already behind schedule. Comparing timelines and costs to Cut and Cover might be interesting when all is said and done.

Unfortunately after the Canada Line, those are cursed words in Vancouver.

People think bored tunnels mean no disruption, but the reality is that there's almost always surface disruption at station boxes, no matter what you do. Cut n' cover is better if you can swing it politically.

[jollyburger]

If you built the stations offset from the road wouldn't you essentially be limited any future construction along the line if the stations were kept at ~20m. You would also need to probably tear down additional buildings for the staging area.

The Barcelona Metro 9 line is like $7.5 billion overbudget and 14 years behind schedule so there's no magical panacea with stacked tunnels.

https://en.ara.cat/misc/line-9-metro-tub...na-over-budget-late-audit_1_1038504.html

[Migrant_Coconut]

Stacked tunnels also mean twice the escalators ($$$ in overhead) and an extra inconvenience for riders on the bottom platform. King Ed is slightly less pleasant than the other stations.

[jollyburger]

Originally Posted by Migrant_Coconut

Stacked tunnels also mean twice the escalators ($$$ in overhead) and an extra inconvenience for riders on the bottom platform. King Ed is slightly less pleasant than the other stations.

Those tiny footprint station designs needed a ton of elevators since it's not really practical to switchback escalators that deep (60-90m)



https://www.tkelevator.com/global-en/new...e-in-barcelonas-metro-stations-1616.html

[jollyburger]

This says labour costs is where Spain saves a lot of money.

Although the material and equipment costs are similar (within 10%) for projects in the United States and in Europe, labor costs are substantially higher in the United States as outlined above. For example, in California the average billing labor rates for qualified tunnel workers is about $70/hr and the average New York labor rate of qualified tunnel workers is at over $100/hr, whereas in Germany (one of the high labor rates countries in Europe) the comparable labor rate is about $30/hr. In other European countries such as Spain, Portugal, Italy, Poland, etc., labor rates are even lower.

https://tunnelingonline.com/why-tunnels-in-the-us-cost-much-more-than-anywhere-else-in-the-world/

[officedweller]

Once the road deck is completed at each station - a much shorter period than an open station excavation - the disruption won't be as noticeable as there will be 4 lanes of traffic restored.
You have to expect disruption for big projects.

[Tvisforme]

Originally Posted by Migrant_Coconut

Stacked tunnels also mean twice the escalators ($$$ in overhead) and an extra inconvenience for riders on the bottom platform. King Ed is slightly less pleasant than the other stations.

Why did they stack the tracks at King Edward, when the stations on either side have their tracks on the same level?

[aberdeen5698]

Originally Posted by jollyburger

Those tiny footprint station designs needed a ton of elevators since it's not really practical to switchback escalators that deep (60-90m)

They should use Paternosters!

They have the advantage of continuous operation without having to wait for a car to make a round trip.

[Changing City]

Originally Posted by Tvisforme

Why did they stack the tracks at King Edward, when the stations on either side have their tracks on the same level?

I'm pretty sure it's because Cambie switches there from the wide boulevard to the narrower street through the section to Broadway (where the shops are). To build a wider, shallower, cut-and-cover section would have effectively closed the entire street. The deeper but narrower slot for stacked lines meant less disruption on the surface. As we know, that didn't exactly work out well for businesses, so it's good to remember it could have been worse! The changing grade, and the benefit of having the tunnels nearer the surface for the Broadway station (and therefore leaving space to thread an east-west route underneath later) put the tracks side-by-side in Broadway-City Hall station. You can see just how huge the excavation for the station was here.

[jollyburger]

Yeah Vancouver Sun article confirms that.

RAV tunnels to be stacked
For much of the Cambie section, the lines will run one atop the other, not side by side



William Boei

Vancouver Sun

Tuesday, January 25, 2005

The Richmond-Airport-Vancouver rapid transit line will run through "stacked" tunnels -- one on top of the other -- rather than side by side for much of its journey beneath Cambie Street, new documents filed by Ravco indicate.

Ravco, the company overseeing the $1.7-billion project for TransLink, filed documents totalling several thousand pages with the province's Environmental Assessment Office in support of its bid for environmental assessment certification.

Open houses will be held this week in Vancouver, Richmond and at the airport to give the public a look at the plan.

The documents reveal no major environmental problems associated with the line, but the public comment process has barely begun and does not end until Feb. 23.

The filings do reveal details of the project that have had little or no public exposure, including details of Ravco's tunnelling plans.

For example, along two stretches of Cambie Street totalling 44 blocks, the northbound tunnel will be stacked on top of the southbound tunnel.

That supposedly reduces "the excavation footprint" and site disturbance during construction, especially for stations, the documents say. The plan calls for construction to leave Cambie's scenic, tree-lined boulevard largely intact.

The north-on-top arrangement will minimize the time it takes northbound passengers to board trains during morning rush hour.

The planned route now includes:

- A side-by-side alignment in a cut-and cover tunnel from Waterfront Station to a point midway between Georgia and Dunsmuir Streets.

- Two separated bored circular tunnels beneath Granville Street to Second Avenue.

- Side-by-side tunnels from Second Avenue to 12th Avenue.

- Stacked tunnels -- the northbound tunnel on top of the southbound tunnel -- from 12th Avenue to 30th Avenue.

- Side-by-side tunnels from 30th Avenue, around Little Mountain, to 37th Avenue.

- Stacked tunnels from 37th Avenue to 63rd Avenue.

- An elevated guideway from 63rd Avenue over the North Arm of the Fraser River to Bridgeport Station.

- Elevated branch lines from Bridgeport Station to Vancouver International Airport, and to Richmond.

Service walkways will run along the entire length of the tunnels to allow emergency evacuations.

"In an emergency, the tunnel ventilation fan system will be activated and fresh air will be supplied to the exit path to protect the evacuees," the documents say. "Emergency lighting and handrails mounted on the tunnel wall will assist in demarcating the exit routes."

Where the tunnels run on top of each other, the evacuation path will be connected to vertical towers at stations so passengers can reach the surface.

The only public input to the Environmental Assessment Office so far is a letter from Richmond resident Bernard Papke complaining about Ravco's plan to build the line on a SkyTrain-like concrete elevated guideway through Richmond.

"Ugly cement pillars" like those supporting the Expo and Millennium SkyTrain lines "will not be acceptable in our community," Papke says in his letter.

However, he does not ask the EAO to order the line to be built at ground level as Richmond city council has done, but to ensure the guideways "feature sweeping curves and gothic-style arches" rather than plain concrete pillars.

The provincial agency will accept public comment through Feb. 23.

Among other documents, one of the environmental assessment reports filed by Ravco reports on drill cores to explore for archeological sites along the RAV Line route.

"No cultural deposits" were identified, the report says, but some areas where there could be deep deposits could not be tested.

"Therefore, there is a small possibility that archaeological sites are present but undiscovered within the RAV development zone."

The report says two sites -- on the south side of False Creek near Cambie and Second, and on the north shore of the Fraser where the line is to cross -- will be explored further before construction begins.

The public can view the RAV Line plans at three open houses:

- Today from 4 to 8 p.m. at the Roundhouse Community Centre, 181 Roundhouse Mews, Vancouver.

- Wednesday from 4 to 8 p.m. in the East Concourse, departures level, of the International Terminal Building at Vancouver International Airport.

- Thursday from 4 to 8 p.m. at Minoru Cultural Centre, 7700 Minoru Gate, Richmond.

RAV TUNNEL PLANS REVEALED:

The northbound tunnel will be stacked on top of the southbound tunnel along parts of the route.

Benefits include:

- The stacked configuration would reduce site disturbance during construction of the $1.7-billion project.

- It would also trim the "excavation" footprint when compared to running two tunnels side by side.

- It would leave intact Cambie Street's tree-lined boulevard.

https://www.gamesbids.com/forums/topic/420-the-rav-project-details-on-the-rapid-transit-line/