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Pittsburgh tunnel widening

Started by Gnutella, May 07, 2015, 02:44:58 PM

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BrianP

Quote from: Gnutella on May 11, 2015, 08:08:37 PM
Quote from: froggie on May 11, 2015, 01:06:22 PM
Widening the existing tunnels is not an option.  You'd have to shut down one portal entirely in order to do it.

:banghead:

I mean, just breeze right on by the pictures in the first post of this topic that prove otherwise!
I don't think that method would work for the Fort Pitt tunnel.  The two bores for the Fort Pitt tunnel are too close together compared to the Nazzano tunnel.

I think this page shows the before image of the Nazzano tunnel. 
http://thecandelabra.blogspot.com/2014/03/galleria-di-nazzano-uneccellenza.html

vs Fort Pitt:
https://www.google.com/maps/@40.437851,-80.013266,3a,75y,239.02h,68.75t/data=!3m4!1e1!3m2!1sRDwHrXc4nyroLi4ymQozTg!2e0
Not to mention the added complexity of the eastern end of the bores being at different elevations.

The Nazzano tunnel seems more analogous to the PA turnpike tunnels e.g.
https://www.google.com/maps/@39.966013,-78.868212,3a,75y,100.09h,81.99t/data=!3m4!1e1!3m2!1sxXr9QoKBawa_3jWNK7-6WA!2e0


Gnutella

Quote from: BrianP on May 12, 2015, 01:13:10 PM
Quote from: Gnutella on May 11, 2015, 08:08:37 PM
Quote from: froggie on May 11, 2015, 01:06:22 PM
Widening the existing tunnels is not an option.  You'd have to shut down one portal entirely in order to do it.

:banghead:

I mean, just breeze right on by the pictures in the first post of this topic that prove otherwise!
I don't think that method would work for the Fort Pitt tunnel.  The two bores for the Fort Pitt tunnel are too close together compared to the Nazzano tunnel.

I think this page shows the before image of the Nazzano tunnel. 
http://thecandelabra.blogspot.com/2014/03/galleria-di-nazzano-uneccellenza.html

vs Fort Pitt:
https://www.google.com/maps/@40.437851,-80.013266,3a,75y,239.02h,68.75t/data=!3m4!1e1!3m2!1sRDwHrXc4nyroLi4ymQozTg!2e0
Not to mention the added complexity of the eastern end of the bores being at different elevations.

The Nazzano tunnel seems more analogous to the PA turnpike tunnels e.g.
https://www.google.com/maps/@39.966013,-78.868212,3a,75y,100.09h,81.99t/data=!3m4!1e1!3m2!1sxXr9QoKBawa_3jWNK7-6WA!2e0


What would have to happen is for the Fort Pitt Bridge end of the tunnel to be dug like this:



(NOTE: The bore would not be the size of the entire circle, just the top half or so.)

What might have to happen is for the tunnel-boring machine to dig 95% of each tube from the Green Tree Hill side of the tunnel with the protective barrier over the traffic, and the last 100' or 200' of each tube on the Fort Pitt Bridge side to be dug without the barrier in order to get their ends to align like I've indicated. This would probably require closure for a time of whichever tube is being expanded while the last 100'-200' is dug.

I'm not saying that expanding the Fort Pitt Tunnel would be easy, just that it's possible. It's also worth noting that a daily traffic count of more than 60,000 vehicles was enough for the Italian government to enlarge the Nazzano Tunnel, and the Fort Pitt Tunnel has a daily traffic count of more than 100,000 vehicles.

ARMOURERERIC

I wish I had the ability to create the kind of mapping yo all do, I could see the boring of 2 additional 3 lane tubes about 500 feet east of the exisiting tubers that lead onto an identical Ft Pitt bridge that only carries 376 thru traffic, severing the required rampage to make the existing Ft Bridge downtown and 279 bound traffic only.  On the west of the hill side have the carrigeways split near the top of Greentree hill with braided ramps to/from Banksville Road.  Saw Mill Run traffic would use the existing carrigeways.

Gnutella

Quote from: ARMOURERERIC on May 14, 2015, 02:56:04 PM
I wish I had the ability to create the kind of mapping yo all do, I could see the boring of 2 additional 3 lane tubes about 500 feet east of the exisiting tubers that lead onto an identical Ft Pitt bridge that only carries 376 thru traffic, severing the required rampage to make the existing Ft Bridge downtown and 279 bound traffic only.  On the west of the hill side have the carrigeways split near the top of Greentree hill with braided ramps to/from Banksville Road.  Saw Mill Run traffic would use the existing carrigeways.

I'm not so sure about building a new bridge because I'm trying to keep the footprint of the highway as small as possible, especially since there's already eight lanes on the Fort Pitt Bridge as it is. Maybe two extra two-lane tubes on each side of the existing tunnel would be the best solution after all, but if the existing tubes get enlarged, then I'd say have the two right lanes going down Green Tree Hill marked for I-376, and the left lane marked for I-279.

I'm currently attempting a reconfiguration of the connector between the Fort Pitt and Fort Duquesne Bridges to make at least one lane from the Fort Pitt Bridge continuous for I-279.

iBallasticwolf2

Quote from: Gnutella on May 14, 2015, 08:16:46 PM
Quote from: ARMOURERERIC on May 14, 2015, 02:56:04 PM
I wish I had the ability to create the kind of mapping yo all do, I could see the boring of 2 additional 3 lane tubes about 500 feet east of the exisiting tubers that lead onto an identical Ft Pitt bridge that only carries 376 thru traffic, severing the required rampage to make the existing Ft Bridge downtown and 279 bound traffic only.  On the west of the hill side have the carrigeways split near the top of Greentree hill with braided ramps to/from Banksville Road.  Saw Mill Run traffic would use the existing carrigeways.

I'm not so sure about building a new bridge because I'm trying to keep the footprint of the highway as small as possible, especially since there's already eight lanes on the Fort Pitt Bridge as it is. Maybe two extra two-lane tubes on each side of the existing tunnel would be the best solution after all, but if the existing tubes get enlarged, then I'd say have the two right lanes going down Green Tree Hill marked for I-376, and the left lane marked for I-279.

I'm currently attempting a reconfiguration of the connector between the Fort Pitt and Fort Duquesne Bridges to make at least one lane from the Fort Pitt Bridge continuous for I-279.

That would make alot of sense to have a continuous lane for I-279
Only two things are infinite in this world, stupidity, and I-75 construction



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