Northern Avenue Bridge Fort Point Channel

Unpopular opinion: the Northern Avenue Bridge was ugly the day it was built. No idea why so much importance is attached to preserving it.
It should be knocked down and replaced with a tied arch bridge. You could have this all done in a week.
 
The pedestrian viewing platform on that most recent render is on the wrong side. A fully built-out Ft. Point Channel will be more visually interesting than the airport across the harbor.
 
It should be knocked down and replaced with a tied arch bridge. You could have this all done in a week.

Agree 100%. It would be cheap, easy to float in and jack up into place, and it would look good too. Win win win.
 
It should be knocked down and replaced with a tied arch bridge. You could have this all done in a week.
Agree 100%. It would be cheap, easy to float in and jack up into place, and it would look good too. Win win win.

Would there be any problem doing that given that the current bridge is a (locked-open) swing bridge? I feel like the feds might have some issues with sticking a fixed bridge over what I think is still technically a navigable waterway. (And rebuilding the approaches to have a higher fixed span isn't a drop-in replacement.)

Of course, the channel still being Coast Guard jurisdiction at all seems a little ridiculous at this point (not that that argument is necessarily persuasive to the feds, well, ever).
 
Every other bridge across the channel (Seaport BLVD, Congress, Summer) is inoperable or was built fixed. Unless there’s something special on the block between Northern and Seaport it shouldn’t make a difference. I like having something there for the pedestrian experience but I agree, scrap it all and build it into the new dam/gates with a simple fixed structure
 
Every other bridge across the channel (Seaport BLVD, Congress, Summer) is inoperable or was built fixed. Unless there’s something special on the block between Northern and Seaport it shouldn’t make a difference. I like having something there for the pedestrian experience but I agree, scrap it all and build it into the new dam/gates with a simple fixed structure

Yeah, but the clearance under Seaport Boulevard's quite a bit higher than the deck level of the Northern Avenue bridge (probably how it could be built as a fixed span). I agree that a fixed span for the Northern Avenue replacement is probably possible, just that it probably requires more than a simple drop-in replacement unless the state can get the channel declared non-navigable.
 
Boston's highest high water is 15.16 feet. From the graphic, the gates would apparently protect against a crest of 15.5 feet. Not much margin, unless the bridge deck provides an additional 2-3 feet, which might explain the chunky blocks instead of svelte piers. (That said, I did not check the crest height for the option, which probably can be found in the engineering drawings.)

Below is the base concept for the barrier. Combining the barrier with a new Northern Avenue bridge is the alternate. Pick your poison

SuAIyrC.png


gQSwYlZ.png


Engineering drawings for both can be found here.

https://www.bwsc.org/news-and-events/news/coastal-stormwater-discharge-analysis-project

^^^ Go to Fort Point
 
Boston's highest high water is 15.16 feet. From the graphic, the gates would apparently protect against a crest of 15.5 feet. Not much margin, unless the bridge deck provides an additional 2-3 feet, which might explain the chunky blocks instead of svelte piers. (That said, I did not check the crest height for the option, which probably can be found in the engineering drawings.)

Below is the base concept for the barrier. Combining the barrier with a new Northern Avenue bridge is the alternate. Pick your poison

SuAIyrC.png


gQSwYlZ.png


Engineering drawings for both can be found here.

https://www.bwsc.org/news-and-events/news/coastal-stormwater-discharge-analysis-project

^^^ Go to Fort Point
Maybe now would be a good time to start talking about a big barrier…
 
Boston's highest high water is 15.16 feet. From the graphic, the gates would apparently protect against a crest of 15.5 feet. Not much margin, unless the bridge deck provides an additional 2-3 feet, which might explain the chunky blocks instead of svelte piers. (That said, I did not check the crest height for the option, which probably can be found in the engineering drawings.)

Below is the base concept for the barrier. Combining the barrier with a new Northern Avenue bridge is the alternate. Pick your poison

SuAIyrC.png


gQSwYlZ.png


Engineering drawings for both can be found here.

https://www.bwsc.org/news-and-events/news/coastal-stormwater-discharge-analysis-project

^^^ Go to Fort Point
I like the location of the proposed pedestrian bridge, further north than the old Northern Ave bridge. The proposed location would provide a shorter and more direct pedestrian and bike route from the Downtown waterfront to the Seaport waterfront.
 
I visited Des Moines Iowa, and, I gotta say, their ability to build dramatic,functional bike-ped-only bridges seems several levels above Boston's game.
Downtown Rehabbing a rail bridge into bike/ped:
Des Moines Union Railway Bridge (south crossing for the downtown riverwalk)
Pedestrian Bridge HDR - Des Moines, Iowa (Project 50/50 - Week 16) by Jason Mrachina, on Flickr
Iowa Women of Achievement Bridge: single-arch, double-bikeway bridge (north crossing for the downtown riverwalk)
The Iowa Women of Achievement Bridge lit with Musco color-changing LED lights reflected in the Des Moines River


44th Street bridge (two arch, single ROW) (over interstate on its approach to downtown)
1678395439680.png


How does Des Moines pull this off and not Boston?
I'd be thrilled to get off-the-shelf derivatives of either of these arch bridges.
 
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I visited Des Moines Iowa, and, I gotta say, their ability to build dramatic,functional bike-ped-only bridges seems several levels above Boston's game.
Downtown Rehabbing a rail bridge into bike/ped:
Des Moines Union Railway Bridge (south crossing for the downtown riverwalk)
Pedestrian Bridge HDR - Des Moines, Iowa (Project 50/50 - Week 16) by Jason Mrachina, on Flickr
Iowa Women of Achievement Bridge: single-arch, double-bikeway bridge (north crossing for the downtown riverwalk)
The Iowa Women of Achievement Bridge lit with Musco color-changing LED lights reflected in the Des Moines River


44th Street bridge (two arch, single ROW) (over interstate on its approach to downtown)
View attachment 35073

How does Des Moines pull this off and not Boston?
I'd be thrilled to get off-the-shelf derivatives of either of these arch bridges.
You said why in your first sentence. They went pure bike/ped. Low cost and focused. They cut down the number of cooks in the kitchen. We try for bike/ped/bus/emergency vehicle/park, scenic overlook, historic recreation.... We end up with a Frankenstein's monster of a design.
 

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