They don't make 'em like this anymore...
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And, uh, sometime in the foreseeable future they'll be gone. Meet the Cape Cod Canal bridges (Sagamore Bridge top, Bourne Bridge bottom). They're both of an achingly beautiful through-arch design that combines a steel truss and suspension bridge into one. These are the only road connections if your destination is Cape Cod, Martha's Vineyard, or Nantucket. While only modestly large compared to modern bridges, when opened in 1935 their 1400-2400 ft lengths and 135 ft deck clearance were impressive.
They're still a sight to behold today, thanks to dramatic road grades and approaches that hide them from view until you're right on top of them.
That age, however, has been an issue. They need constant maintenance, the roadways are too narrow, there's no shoulders, no separation between the pedestrian walkways and road surface, and the on-Cape surface road interchanges are utter garbage that cause massive seasonal traffic delays. During summer holiday weekends it's not uncommon to be crawling in traffic a mile or more away from a bridge.
So, the obvious solution is to replace them. That's a problem though, as these bridges are veritable sculptures in steel. Doing it wrong risks destroying a lot of regional character and losing public goodwill. There's also the issue of the bill. They were originally built and to this date are maintained by the Army Corps of Engineers (also responsible for the canal), but this is apparently not enough to secure federal funding. This has left USACE and MassDOT pointing fingers at each other for the replacements, although whatever the case may be it's been decided that the replacement bridges will be fully owned by the state.
But, I digress. Let's get back to my point about bridge design. The project is underway, and while we're still years away from even an environmental impact study, some preliminary designs have been released to the public for scrutiny:
First up is this cable stayed design. On it's own it's nice, I guess, but the type is kind of overused in modern times and it's really at home in the city. It sticks out like a sore thumb in the otherwise mostly natural setting of the canal.
Next proposal is this box girder bridge which no fuck you MassDOT go shove a traffic cone up your ass how dare you
Lastly, we have this contemporary interpretation of the existing bridges:
This has obviously met with the most public approval, and they knew that'd be the case that since the proposal documents themselves recommend it. I dunno, though. I feel like they're not as pretty and I hope they can refine the design a bit. The steel trusses have a sort of flowing form that's lacking in this proposal.
These renderings were released back in May, with no further updates as to what design they're leaning towards. Like I said, construction is still a loooong way off. While MassDOT and USACE received a grant to start the planning process, they were denied funding from this round of Biden's big infrastructure bill. You can read more about the project here.
The person reading this is a doo-doo head
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But anyway, the bridges are clearly at capacity during the summer, and presumably high maintenance as well. Shame to see such attractive bridges go, but it doesn't seem like adding extra spans to preserve the originals would be a good use of money.
I disagree on the cable-stayed being a city thing, but agree completely that anyone who wants the concrete box girder should be immediately removed from the project.
It seems like it would make sense for a Bourne Bridge replacement to incorporate rail as well, to replace the railroad bridge. That's roughly the same age and presumably is also high maintenance, with the added problem of blocking the canal when it is used.
Also, it feels like if they are building new bridges, they should boost the height 50% to allow the possibility of New Panamax ships, though probably the detour around the Cape isn't long enough (and Boston isn't a major enough port), to justify the extra expense of accommodating such behemoths.
Edit:
We really need more attractive ways to keep people from falling/jumping off of bridges.
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@facw said in They don't make 'em like this anymore...:
It seems like it would make sense for a Bourne Bridge replacement to incorporate rail as well
I don't know if rail can make the required grade for clearance, but with the recent push for year-round commuter rail service who knows what'll happen.
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@facw said in They don't make 'em like this anymore...:
anyone who wants the concrete box girder should be immediately
removed from the projectthrown off said bridge.FTFY
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I don't know if rail can make the required grade
Okay so I'm having trouble sleeping and as a result ended up doing some number crunching. Generally rail lines in the US top out at a 2.2% grade. Any more and you may start needing special consists, especially for heavier freight trains.
The LOWEST of the four bridge approaches starts at about 30 ft above sea level, so to make the current 135ft clearance at 2.2%...
The rail line would have to leave highway grade and start climbing nearly a mile before the canal.
Best I can find the steepest regular passenger rail line in the US is Raton Pass in New Mexico. It hits 3.5% grade in parts, which still means almost 2/3 mile of runup to the canal bridge.
Plus there's the matter of connecting to the existing rail line. After it crosses the lift bridge at the south end of the canal it actually runs north under both bridges almost at canal level. Linking up to that from either bridge would require an immensely large loop and a LOT of eminent domain.
Honestly the best solution for rail is just to bury the existing crossing, although that limits further deepening of the canal.
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@EssExTee
Nice bridges. Reminds me of one of the bridges in Merseyside.
Up front is the (1868) Ethelfleda Bridge (aka Runcorn Railway Bridge), then the (1961) Silver Jubilee Bridge and at the back, the (2017) Mersey Gateway Bridge.
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@EssExTee said
1935
@Svend said
1868
Oh for the days when “if it looks right, it is right” was state of the art in engineering. It gave us some things which looked very right indeed.
Jagroen fan & custodian of camellids. GT86, Octavia VRS, Pajero, Leaf
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@іди-на-хуй-Влад-formerly-known-as-Distraxi
There's Tarr Steps, Somerset. 1,000BC.
Exe Bridge, Exeter. 1215AD
Ironbridge, Shropshire. 1779AD
Gateshead Millennium Bridge, Gateshead. 2001
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@EssExTee I got nothing to add except the Gordie Howe international Bridge is coming along nicely.
Good luck on the funding. Only reason we got this is because Canada agreed to pay for it.
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Nice writeup of the situation!
We have similar issues with the Mississippi River bridge (Horace Wilkinson Bridge, but nobody calls it that). Traffic backs up for miles but it's not just the bridge that's causing it. Eastbound traffic starts with three lanes. Partway up the approach, a lane merges in from the right. That slows things down a bit, but things get really messy on the other side.
The signage makes you think there's only one lane that will keep you on I-10. People not familiar with the area will start merging left from the right lane. Others are merging right from the left lane. End result is a major traffic jam that can back up for miles.
Compounding the problem is that the two right lanes effectively become one after the highway turns south because the rightmost lane becomes an exit only lane.
Where does that exit go? It wasn't part of the original design but a local official threw a fit, saying that it was an injustice to cut off their neighborhood. There's another exit that provides better access a mile before this exit and yet another half a mile after this exit.
This is the only place, coast-to-coast, where I-10 is restricted to one lane by design.
Fortunately, as part of the widening project for I-10 east of the bridge, this is supposed to be corrected.
There are no plans to replace the current bridge, but they are talking about building a new one several miles south. The idea is to build a way for through traffic to go around Baton Rouge. It's the old idea of the interstates bypassing the small towns but taken to a much grander scale.
Never discount the possibility that you might live through it.
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@EssExTee I am not trying to partypoop anything here today...
Bridges - i think it would be more beneficial if I could appreciate bridges more. To me it's a structure that provides transportation from one shore to another.
Some bridges are just logs thrown across. Other bridges are concrete. Some others are ropes. I do not know how one bridge is different from another. Some engineers cream their panties looking at some bridges and I look at it like a dog looks at a side of a building. Yep. I can pee on it.Show me. teach me. why should i be excited about some bridge vs another?
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@partypooper2012
Just my peneth, it's design, form, architecture, function and how they mix together, being sympathetic to it's surroundings (you don't want some god awful structure planted down in an area of outstanding beauty), but then you may want something that stands out and becomes a focal point of the area, something that pushes technology, etc...
It's not about just spanning an area, a bridge like a building, car, etc... It's a working, function piece of art that done right will be there for generations. -
@Svend yes. i get that. I do not know bridge capacity and that makes my butt pucker up.
I have seen what appears to be a solid sturdy bridge wobble in the wind and collapse. I have seen brand new overpass bridge collapse 3 days after being installed.
I have heard of bridges collapsing after boat strike in the fog and bridge users plunging to their deaths.
I have a fear of 18 wheeler changing lanes into me as I am on either left or right most lanes. Forcing me off the bridge.
Beauty is secondary to stability of a bridge in my book.
I need to know capacities. I need to know stabilities. I need to know how sturdy that railing is - how much force could it withhold. I need to know inspection certificate dates like they have on elevators. -
@BicycleBuck said in They don't make 'em like this anymore...:
It's the old idea of the interstates bypassing the small towns but taken to a much grander scale.
I read a book several years ago about the building of the American road system which was really interesting. Turns out Eisenhower wanted interstates to connect major cities, but not cut through them. But he wasn't much of a detail man, and he never actually read any bills. He had his aids do that for him. So when they said, "Here's that highway bill you wanted," he just blindly signed it. He was PISSED when he learned that they were cutting the interstates through the cities, which happened when he was visiting the construction site of such a project.
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@Shop-Teacher said in They don't make 'em like this anymore...:
@BicycleBuck said in They don't make 'em like this anymore...:
It's the old idea of the interstates bypassing the small towns but taken to a much grander scale.
I read a book several years ago about the building of the American road system which was really interesting. Turns out Eisenhower wanted interstates to connect major cities, but not cut through them. But he wasn't much of a detail man, and he never actually read any bills. He had his aids do that for him. So when they said, "Here's that highway bill you wanted," he just blindly signed it. He was PISSED when he learned that they were cutting the interstates through the cities, which happened when he was visiting the construction site of such a project.
And now we have grant programs to tear them down or develop user-friendly ways to reconnect the communities split by the interstates. Baton Rouge is a great example. I-10 divides it north and south, I-110 divides it east and west. Major east-west roads further subdivide it and the state actively fights any attempts to make them more pedestrian & bicycle friendly. They don't even want to add pedestrian crossings since they mess up the optimized traffic flow.
Never discount the possibility that you might live through it.
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@partypooper2012
Great detail has to be put into a bridge.
Which is amazing as it is detailed from terrain either side of the bridge and below it, what materials to use and how best to use them, not just what they'll need to be able to carry now but what they may have to carry in 50, 60, 70, etc... years time. Weather, not just norms but worst known or believed possible conditions.
Loads of studies, re-drawings, re-examinations, model testing and so on.
There are a number of documentaries, certainly in the UK on them, to watch.
With existing ones it's maintenance, etc..
By all accounts the US infrastructure hasn't been maintained all that well with third party and private companies monitoring dams and slipways, bridges crumbling, walkways collapsing, etc... -
@Svend Yep. I don't know of a single field in US that is thriving.
Education - trash
Healthcare - trash
Transportation - trash
Communication - trash
Infrastructure - trash -
@іди-на-хуй-Влад-formerly-known-as-Distraxi @Svend
1868... 1935... 1961
Then there's the Piscataqua River Bridge that carries I95 between the NH and Maine borders. It was built all the way in 1972.
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@Vondon302 because of course it's named after a hockey player
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I do like consistency in bridge design from an esthetic viewpoint. St. Louis has a number of bridges across the Mississippi, and they are all different styles.
Portland Oregon goes even further in bridge diversity.
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@Roadkilled and then there's fukkin Pittsburgh
The person reading this is a doo-doo head
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@Vondon302 Or, more to the point of Gordie Howe, 2 countries had to fight over the funding and Canada lost
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@EssExTee
Cincinnati -
@BicycleBuck said in They don't make 'em like this anymore...:
And now we have grant programs to tear them down or develop user-friendly ways to reconnect the communities split by the interstates. Baton Rouge is a great example. I-10 divides it north and south, I-110 divides it east and west. Major east-west roads further subdivide it and the state actively fights any attempts to make them more pedestrian & bicycle friendly. They don't even want to add pedestrian crossings since they mess up the optimized traffic flow.
They completely destroyed a lot of communities. The damage done can never be repaired.
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I have no problem with the concrete bridge. It's very minimalist and IMO does the least amount of intrusion on the viewshed/horizon. The arches underneath can be dressed up pretty nicely and no cables to worry about.
This is objective and not considering the expectation that the bridge needs to be aesthetically pleasing or historically accurate, just functional and as low-profile and low-maintenance as possible.
@svend I have a couple old film photos of myself exploring some of those Bronze Age short-span stone bridges in Somerset and Devon. So low-tech, but I can imagine the idea of keeping your feet dry was a big leap forward in the era. Or not having to balance while walking across a log or stepping stones.
Iron Bridge might be the worldwide symbol of the very earliest days of the Industrial Revolution.
Just imagine Ryan Reynolds' low-cost backup stunt double.
