I had the pleasure tonight of attending an ASCE presentation on concept studies for the Bayonne Bridge. Short synopsis: In order to fit the new Panamax ships (213' tall) under the Bayonne Bridge, which currently has a 150' clearance, it either has to be raised or replaced. Off the table are options to construct a crossing in a different location or remove it entirely. The story is mildly complicated by the fact that the arch would have to remain because it's eligible for the National Historical Register (why it's not already on it is beyond me), but apparently it may be okay to leave the arch intact if a new bridge is built. The new bridge would likely be cable-stayed; duplicating the current design would probably not be cost effective (although it would solve the aforementioned problem).
Now to the fun part. The option that piqued my interest and may be the frontrunner is to keep the bridge as it is now, simply raising the entire thing 65 feet. Raising the roadway within the arch would just destroy the artistic profile, so that's pretty low on the alternatives rating. Raising the bridge would apparently be 30% heavier than any object ever lifted anywhere before. The bearings required to take the bridge forces as it is raised would cost nearly a million dollars EACH (times 8 - one at each end of the top and bottom chord on each side - or is that times 16?). However, it still comes out half a billion dollars cheaper than a new bridge.
I really hope they go ahead and raise the existing bridge. Now, I also don't think there are really traffic volumes there to warrant a bridge at all, but as I said, it's staying. As part of raising it, they would redeck it so it could finally have 12' lanes (instead of 10') and adequate shoulders. The cable-stayed bridge is pretty, especially with the arch behind it (and it would still have to be raised, just not as high and without the extra weight of the roadway on it), but it's just not the same. The issue with the new clearance is that the interchange with CR 501 in Bayonne would be blown out. Pending a traffic study, it was suggested the ramps may not be needed at all. I will differ - the City of Bayonne would likely not accept any alternative that removes such a critical access in the heart of the city. There's probably enough room to compensate for the grade differential and retain the connection, but preliminary and final design are still a few years down the road.
I do know a few more items than that - but since this is still at a preliminary stage, I don't see why I need to go into detail on uncertainties. Panamax ships are supposed to be operational in 2015, and this bridge likely would not be raised until that year - work completing in 2016-2017.
I'm surprised the Bayonne only carried 21,755 back in 2005 (from Page 110 of http://www.nyc.gov/html/dot/downloads/pdf/bridgetrafrpt05.pdf (http://www.nyc.gov/html/dot/downloads/pdf/bridgetrafrpt05.pdf)); I was expecting at least 35,000.
Port Authority commits $1B to Bayonne Bridge fix (http://content.usatoday.net/dist/custom/gci/InsidePage.aspx?cId=delawareonline&sParam=34537773.story)
QuoteBAYONNE, N.J. (AP) – The Port Authority of New York and New Jersey has agreed to spend up to $1 billion to find a solution to the Bayonne Bridge height problem.
The 151-foot-high road deck on the span connecting Bayonne with Staten Island is not high enough to accommodate the next generation of larger container ships.
Ships pass under the bridge to reach the Newark Bay port area.
The Army Corps of Engineers has said the best solution is to raise the bridge deck to 215 feet.
The Port Authority says options include jacking up the current road deck, creating a lift bridge mechanism at the center of the span or building a new, taller bridge.
The Port Authority said Tuesday that a prioritized list of alternatives will be completed by the end of the year.
I don't know specifics on this one, but does raising the Bayonne allow light rail to be built across to Staten Island?
Quote from: Zmapper on September 20, 2010, 04:07:54 AM
I don't know specifics on this one, but does raising the Bayonne allow light rail to be built across to Staten Island?
Light rail could already have been built across the Bayonne Bridge. Raising it has nothing to do with viability - if anything, it makes it harder to get the rail up to the bridge on either side. It's politics, residential concerns, and money.
Port Authority plan: Raise Bayonne Bridge roadway (http://content.usatoday.net/dist/custom/gci/InsidePage.aspx?cId=delawareonline&sParam=35410097.story)
QuoteBAYONNE, N.J. (AP) – The Port Authority of New York and New Jersey says raising the roadbed is the best way to fix the Bayonne Bridge so larger ships can pass underneath.
The 151-foot-high road deck on the span connecting Bayonne with Staten Island is not high enough to accommodate the next generation of larger container ships.
Ships pass under the bridge to reach Newark Bay port terminals
The Port Authority said Wednesday that raising the bridge deck to 215 feet is the most cost-effective solution and will have the least environmental and neighborhood impact. If approved, crews would reconstruct the existing approaches, ramps, and main span roadway to a higher elevation that would allow the crossing to accommodate larger ships for years to come.
Officials say this solution would also minimize visual and physical impacts to the historic bridge and seeks to preserve its iconic arch.
In October, the authority agreed to provide up to $1 billion in its capital planning process to help finance a Bayonne Bridge solution.
"This (raising plan) is an important next step to developing a cost-effective solution to address the Bayonne Bridge navigational issues," Port Authority Executive Director Chris Ward said.
Other options considered included installing a lift bridge mechanism at the center of the span or building a new, taller bridge. The Port Authority said its staff has begun working on engineering issues related to raising the roadbed.
"This plan provides fiscally appropriate and environmentally sound solution," Gov. Chris Christie said. "Modernizing the Bayonne Bridge is essential to maintaining port access for the next generation of transportation and shipping vessels and crucial to the economic future of New Jersey and the region. International trade is a key piece of our economic development strategy."
Quote from: AARoads on December 29, 2010, 03:57:57 PM
Port Authority plan: Raise Bayonne Bridge roadway (http://content.usatoday.net/dist/custom/gci/InsidePage.aspx?cId=delawareonline&sParam=35410097.story)
I've seen the plan, and this makes the arch terribly ungainly because only the roadway is being raised, not the arch itself. I'm sure there is no plan to improve that, either.
[I think this is an appropriate "bump" of an old thread]
NJ.COM: EPA questions Bayonne Bridge environmental assessment by Coast Guard (http://www.nj.com/news/index.ssf/2013/02/epa_questions_bayonne_bridge_e.html)
TOLLROADSnews: USEPA slow-tracks Obama's fast-track for Bayonne Bridge NY-NJ (http://www.tollroadsnews.com/node/6409)
So the EPA doesn't want the port to expand it operations beucase that would increase pollution? It seems like their dissent has nothing to do with the changes to the bridge or even the dredging of what has to be a very polluted pile of silt. Seems backwards to me.
Some shots from this weekend. There are a few more if you click through.
New embankment at the Staten Island side
(https://farm8.staticflickr.com/7515/16090458419_35ffc42d18.jpg) (https://flic.kr/p/qvRNGT)
Former northbound side seems to be being dismantled while traffic is one lane each way on the west (former southbound) side
(https://farm8.staticflickr.com/7551/16276584855_ea2022040e.jpg) (https://flic.kr/p/qNiKBn)
South tower being extended upward using faux-antique girders
(https://farm8.staticflickr.com/7506/16089218440_dea5a63875.jpg) (https://flic.kr/p/qvKs6W)
Launching crane, one of two poised at north and south ends
(https://farm8.staticflickr.com/7474/16275758812_103794b2f0.jpg) (https://flic.kr/p/qNew4f)
Just curious, but while they are there raising the road deck, I'm assuming the bridge is riveted together. Any thought about replacing them with those new high strength bolts?
I'm not anticipating an earthquake, but nor'easters, industrial accidents, error in navigation, yada, yada, yada, mebbee the bridge needs to be as strong and up to date all over as possible ?
Quote from: Pete from Boston on January 14, 2015, 12:15:00 AM
Some shots from this weekend. There are a few more if you click through.
This is a neat project, though I do wonder if the bridge will "look right" after it is complete.
Thanks for sharing the photographs.
It won't, but it would have been the largest item ever lifted if they pursued the option that kept the deck in the same relative place. I will miss its familiar form.
Quote from: Pete from Boston on January 15, 2015, 02:58:38 PM
It won't, but it would have been the largest item ever lifted if they pursued the option that kept the deck in the same relative place. I will miss its familiar form.
That would have been an
awful lot of weight to try and raise over 50 feet! I suppose the load could have been reduced by removal of the bridge deck, but still, that arch is not light.
Quote from: Jardine on January 14, 2015, 11:46:33 PM
Just curious, but while they are there raising the road deck, I'm assuming the bridge is riveted together. Any thought about replacing them with those new high strength bolts?
I'm not anticipating an earthquake, but nor'easters, industrial accidents, error in navigation, yada, yada, yada, mebbee the bridge needs to be as strong and up to date all over as possible ?
I don't think that is part of it. They'll probably have already inspected the entire bridge to make sure what they have is in tiptop shape.
Would raising the bridge deck lower clearance for trucks?
Quote from: mapman1071 on January 16, 2015, 11:52:19 AM
Would raising the bridge deck lower clearance for trucks?
No, it's going to go through a different part of the arch and it will of course have full Interstate clearance (16'-6" I believe) because of the port areas it connects.
Some shots from today:
(https://farm1.staticflickr.com/770/32272185802_a48abd315c_h.jpg)
(https://farm1.staticflickr.com/717/32302281001_85740b158c_b.jpg)
(https://farm1.staticflickr.com/720/31611580983_93a75064a3_b.jpg)
More at https://flickr.com/photos/93617544@N08/sets/72157679378431905
Nice pics. I take that the other half of the road will be built after the original approaches have been dismantled.
I was wondering how they got the new roadway piers into place with the old one there. Now I see they got part of the current roadway "cut out" to allow the new deck's piers. Great caption of the whole project.
Quote from: roadman65 on January 21, 2017, 09:06:02 AM
Nice pics. I take that the other half of the road will be built after the original approaches have been dismantled.
I was wondering how they got the new roadway piers into place with the old one there. Now I see they got part of the current roadway "cut out" to allow the new deck's piers. Great caption of the whole project.
It's really something to visit in person. The piers go seemingly right through the existing deck. It took some close inspection to reveal how they got it done. And yes, they will open the new half-roadway to 2 lane traffic (which is all they're running now anyway) before dismantling the original roadway and building the rest. 440 doesn't need more than 2 lanes here, it's all just for safety.
I will never take another photo of the bridge. The last ones I took captured the new deck closing in on the old. The beautiful, graceful lines will be lost forever. Ammann will be spinning in his grave.
Quote from: Alps on January 21, 2017, 04:35:02 PM
Quote from: roadman65 on January 21, 2017, 09:06:02 AM
Nice pics. I take that the other half of the road will be built after the original approaches have been dismantled.
I was wondering how they got the new roadway piers into place with the old one there. Now I see they got part of the current roadway "cut out" to allow the new deck's piers. Great caption of the whole project.
It's really something to visit in person. The piers go seemingly right through the existing deck. It took some close inspection to reveal how they got it done. And yes, they will open the new half-roadway to 2 lane traffic (which is all they're running now anyway) before dismantling the original roadway and building the rest. 440 doesn't need more than 2 lanes here, it's all just for safety.
I will never take another photo of the bridge. The last ones I took captured the new deck closing in on the old. The beautiful, graceful lines will be lost forever. Ammann will be spinning in his grave.
While I am not imposing the same moratorium as you, I am right there with you. From the moment this project was proposed, I cringed. Ruins the proportions and lines. The grace of the approachway arches will also be lost in favor of the ungainly, artless concrete pillars going in.
Quote from: Alps on January 21, 2017, 04:35:02 PM
I will never take another photo of the bridge. The last ones I took captured the new deck closing in on the old. The beautiful, graceful lines will be lost forever. Ammann will be spinning in his grave.
I read someplace (perhaps on the PANYNJ Web site) that project managers got "approval" from the Ammann family (his children?) to raise the deck of the roadway with the understanding that the arch would remain as before.
Quote from: Pete from Boston on January 22, 2017, 08:51:23 PM
While I am not imposing the same moratorium as you, I am right there with you. From the moment this project was proposed, I cringed. Ruins the proportions and lines. The grace of the approachway arches will also be lost in favor of the ungainly, artless concrete pillars going in.
While respecting your opinions, I am not as negative as you guys, since the only viable alternative seems to have been an entirely new bridge, presumably leading to the eventual removal of the arch.
Do I like the "new" appearance of the bridge? No, not at all. But it had to be raised, and it seems that raising the arch was apparently not workable.
Quote from: cpzilliacus on January 22, 2017, 10:10:42 PM
Quote from: Alps on January 21, 2017, 04:35:02 PM
I will never take another photo of the bridge. The last ones I took captured the new deck closing in on the old. The beautiful, graceful lines will be lost forever. Ammann will be spinning in his grave.
I read someplace (perhaps on the PANYNJ Web site) that project managers got "approval" from the Ammann family (his children?) to raise the deck of the roadway with the understanding that the arch would remain as before.
Quote from: Pete from Boston on January 22, 2017, 08:51:23 PM
While I am not imposing the same moratorium as you, I am right there with you. From the moment this project was proposed, I cringed. Ruins the proportions and lines. The grace of the approachway arches will also be lost in favor of the ungainly, artless concrete pillars going in.
While respecting your opinions, I am not as negative as you guys, since the only viable alternative seems to have been an entirely new bridge, presumably leading to the eventual removal of the arch.
Do I like the "new" appearance of the bridge? No, not at all. But it had to be raised, and it seems that raising the arch was apparently not workable.
Raising the arch was one of the options. Another option was keeping just the arch, moving it a bit, and building a new bridge. Raising the arch had the issue of the approaches becoming much longer, which became too expensive due to interchanges on either side.
I've probably already said this upthread, but I recall the phrase "largest object ever lifted" being used in regard to the arch-raising option.
Quote from: Alps on January 22, 2017, 10:48:19 PM
Raising the arch was one of the options. Another option was keeping just the arch, moving it a bit, and building a new bridge. Raising the arch had the issue of the approaches becoming much longer, which became too expensive due to interchanges on either side.
I think you said (upthread) that raising the arch (because of the weight) would have been an enormously difficult thing to do (but the cool factor would have been approaching infinity to raise it).
Again, I respect and agree with your comments about the arch not looking nearly as nice when this job is completed, but I am very glad that the iconic arch will still be standing there.
Yes, the bridge won't be the same once the new roadway is solely the bridge. Even with the iconic arch still in place, the beauty of the bridge is altered now forever.
Also the arched piers on both sides supporting the approachways was a great feature of the bridge that the new modern piers can't hold a candle to those. Only the Outerbridge Crossing will have those as even the Goethals will never have them once the old bridge is history.
Hey, at least it's not being replaced with yet another cable stayed bridge. In Vancouver, BC, they replaced the 50 year old Port Mann Bridge which was a beautiful arch bridge (and the inspiration for the design of Portland's Fremont Bridge) with an extremely ugly looking cable stayed bridge (and yes, it is ugly!) in 2012, and I am still very disappointed about this. They could have just twinned the bridge, but no. They gave some justification like "well, we're going to have to replace it in fifty years, so we're saving money in the long run" even though the original arch bridge was designed to last 100 years, but frankly, I was sad to see it go. :(
So, it could be worse, guys...
Quote from: compdude787 on January 25, 2017, 02:52:34 AM
Hey, at least it's not being replaced with yet another cable stayed bridge. In Vancouver, BC, they replaced the 50 year old Port Mann Bridge which was a beautiful arch bridge (and the inspiration for the design of Portland's Fremont Bridge) with an extremely ugly looking cable stayed bridge (and yes, it is ugly!) in 2012, and I am still very disappointed about this. They could have just twinned the bridge, but no. They gave some justification like "well, we're going to have to replace it in fifty years, so we're saving money in the long run" even though the original arch bridge was designed to last 100 years, but frankly, I was sad to see it go. :(
So, it could be worse, guys...
I agree, but mostly because I come from the time before cable-stayed bridges were common in the US. I like lots of steel.
That said, the design variety of the several very large cable-stayeds in New York is a little blah. The Goethals, Tappan Zee, and Kosziusco are all very similar. Yes, the same could be said of the Whitestone, Throgs Neck, and Verrazano, but I think they could have made these new three a little more distinctive.
I may be younger than you, but I still think cable stayed bridges get a bit monotonous once you have more than 2 or three in a city. At first, yeah, they're cool and all, but eventually they get to be boring.
I don't get the attraction of cable stayed bridges. They definitely don't have the graceful curves of arch bridges and suspension bridges, nor the classic charm of cantilever and truss bridges (or covered bridges). They're just one step above a simple beam bridge. Plus they're so overused these days that they're practically a cliche!
Quote from: vdeane on January 25, 2017, 09:45:36 PM
I don't get the attraction of cable stayed bridges. They definitely don't have the graceful curves of arch bridges and suspension bridges, nor the classic charm of cantilever and truss bridges (or covered bridges). They're just one step above a simple beam bridge. Plus they're so overused these days that they're practically a cliche!
Agreed 100%.
I like to know why DelDOT used one on DE 1 in Sussex County, DE to replace a Bascule Span Bridge instead of your typical high rise that usually replaces an inlet crossing.
I know in Brunswick, GA they redid the Sidney Lanier Bridge that was a vertical lift span with the current cable stayed crossing because the Port Authority wanted big ships that would not pass beneath a regular high rise. However, this channel along Delaware's coast is not a major port for commerce and mainly for pleasure boats.
Quote from: roadman65 on January 26, 2017, 12:42:23 PM
I like to know why DelDOT used one on DE 1 in Sussex County, DE to replace a Bascule Span Bridge instead of your typical high rise that usually replaces an inlet crossing.
I know in Brunswick, GA they redid the Sidney Lanier Bridge that was a vertical lift span with the current cable stayed crossing because the Port Authority wanted big ships that would not pass beneath a regular high rise. However, this channel along Delaware's coast is not a major port for commerce and mainly for pleasure boats.
Using Wikipedia, for what that's worth, it sounds like a history of scouring has undone many bridges there. Thru just 80 years, 5 bridges have been built on this site; with the other 4 either collapsing or in danger of collapsing. Almost sounds like a long history of bad engineering.
The current bridge was built, it appears, to withstand changes in the ocean and inlet currents for decades to come. It certainly does seem overbuilt for what it needs to cross though!
They specifically didn't want piers in the canal as they posed a navigation hazard.
Quote from: jeffandnicole on January 26, 2017, 01:19:36 PM
Quote from: roadman65 on January 26, 2017, 12:42:23 PM
I like to know why DelDOT used one on DE 1 in Sussex County, DE to replace a Bascule Span Bridge instead of your typical high rise that usually replaces an inlet crossing.
Using Wikipedia, for what that's worth, it sounds like a history of scouring has undone many bridges there. Thru just 80 years, 5 bridges have been built on this site; with the other 4 either collapsing or in danger of collapsing. Almost sounds like a long history of bad engineering.
The current bridge was built, it appears, to withstand changes in the ocean and inlet currents for decades to come. It certainly does seem overbuilt for what it needs to cross though!
Scouring was indeed a big problem with at least the 1965 Indian River bridge-it underwent frequent underwater checks in its last years after one inspection revealed that the narrow channel was about 90' deep and there wasn't really much holding up the bridge. Large boulders were routinely dumped into the channel. (Fun fact: highest point in Sussex Co is only about 75'.) I'm too lazy to see if Wikipedia covers it adequately, but the first attempt at building the newest bridge was halted after it was noticed that all the fill (and the ground it was sitting on, namely wet sand) had sunk several feet. Supposedly the tidal flow would be enough to generate serious electricity, if anybody could figure out how to keep the turbines from washing away.
Back to Bayonne...
Quote from: davewiecking on January 26, 2017, 05:12:06 PM
Quote from: jeffandnicole on January 26, 2017, 01:19:36 PM
Quote from: roadman65 on January 26, 2017, 12:42:23 PM
I like to know why DelDOT used one on DE 1 in Sussex County, DE to replace a Bascule Span Bridge instead of your typical high rise that usually replaces an inlet crossing.
Using Wikipedia, for what that's worth, it sounds like a history of scouring has undone many bridges there. Thru just 80 years, 5 bridges have been built on this site; with the other 4 either collapsing or in danger of collapsing. Almost sounds like a long history of bad engineering.
The current bridge was built, it appears, to withstand changes in the ocean and inlet currents for decades to come. It certainly does seem overbuilt for what it needs to cross though!
Scouring was indeed a big problem with at least the 1965 Indian River bridge-it underwent frequent underwater checks in its last years after one inspection revealed that the narrow channel was about 90' deep and there wasn't really much holding up the bridge. Large boulders were routinely dumped into the channel. (Fun fact: highest point in Sussex Co is only about 75'.) I'm too lazy to see if Wikipedia covers it adequately, but the first attempt at building the newest bridge was halted after it was noticed that all the fill (and the ground it was sitting on, namely wet sand) had sunk several feet. Supposedly the tidal flow would be enough to generate serious electricity, if anybody could figure out how to keep the turbines from washing away.
The pre-1965 Indian River bridge was indeed a bascule bridge that was undermined in the March 1962 nor'easter and closed well into that summer.
Although he was just an R&D tech, my late stepdad would probably say about the current bridge, "That bridge was 200% overdesigned!"
ixnay
Yeah they could have came up with another design for sure.
Lets try to move this over to the Delaware thread, as we derailed. And I mean "We" meaning yours truly included.
Quote from: roadman65 on January 27, 2017, 11:56:12 AM
Yeah they could have came up with another design for sure.
Lets try to move this over to the Delaware thread, as we derailed. And I mean "We" meaning yours truly included.
I just did my part to this end by copying and pasting my previous post and the quotes therein to said DE thread. See you over there!
ixnay
Update to the Project.
Upper deck is now the only deck, lower deck removal being done, and is now Cashless.
http://www.nj.com/hudson/index.ssf/2017/02/bayonne_bridge_opens_to_drivers_but_construction_f.html
Quote from: vdeane on January 25, 2017, 09:45:36 PM
I don't get the attraction of cable stayed bridges. They definitely don't have the graceful curves of arch bridges and suspension bridges, nor the classic charm of cantilever and truss bridges (or covered bridges). They're just one step above a simple beam bridge. Plus they're so overused these days that they're practically a cliche!
Cable stayed bridges can, with modern construction techniques, be built faster than suspension bridges. Because of this, and because they use less material (they don't need anchorages), they are also less expensive. So the attraction of them is that they're cost effective. It doesn't really make economic sense to build a suspension bridge unless you need to span a fairly wide distance (>3,000 feet or so) in one go - the reason for this being that a suspension bridge can span the same distance with shorter towers than a cable stayed bridge can, so there comes a point where the cost saved by building shorter towers exceeds the extra cost of anchorages.
It's unfortunate since I, like you, prefer suspension bridges aesthetically. But practical considerations have made them outmoded in most circumstances. We will therefore continue seeing more cable stayed bridges until changing circumstances make a different (possibly newer) design cheaper.
Watching SteveG's video, the view reminds me of the few times I've crossed the Reedy Point Bridge on DE 9.
When the other two lanes reopen, it'll look from the dashboard like a mishmash of the Reedy Point and Summit (DE 896) Bridges. Both of those bridges cross the Chesapeake and Delaware Canal.
ixnay
Quote from: Duke87 on April 02, 2017, 10:06:35 PM
Quote from: vdeane on January 25, 2017, 09:45:36 PM
I don't get the attraction of cable stayed bridges. They definitely don't have the graceful curves of arch bridges and suspension bridges, nor the classic charm of cantilever and truss bridges (or covered bridges). They're just one step above a simple beam bridge. Plus they're so overused these days that they're practically a cliche!
Cable stayed bridges can, with modern construction techniques, be built faster than suspension bridges. Because of this, and because they use less material (they don't need anchorages), they are also less expensive.
Also, if four stay cable towers are used (instead of two), the resulting bridge is stiff enough to carry railroad tracks if desired. Suspension bridges do not generally carry railroads because by their nature, they are rather flexible.
Quote from: cpzilliacus on April 05, 2017, 02:06:18 AM
Also, if four stay cable towers are used (instead of two), the resulting bridge is stiff enough to carry railroad tracks if desired. Suspension bridges do not generally carry railroads because by their nature, they are rather flexible.
The Manhattan, Williamsburg, and Ben Franklin bridges would beg to differ. Other countries have even bigger bridges that carry tracks like the Tsing Ma Bridge in Hong Kong and the Øresund Bridge between Denmark and Sweden
Quote from: MrDisco99 on April 05, 2017, 01:29:02 PM
Quote from: cpzilliacus on April 05, 2017, 02:06:18 AM
Also, if four stay cable towers are used (instead of two), the resulting bridge is stiff enough to carry railroad tracks if desired. Suspension bridges do not generally carry railroads because by their nature, they are rather flexible.
The Manhattan, Williamsburg, and Ben Franklin bridges would beg to differ. Other countries have even bigger bridges that carry tracks like the Tsing Ma Bridge in Hong Kong and the Øresund Bridge between Denmark and Sweden
Not without problems, though. The Manhattan Bridge flexes visibly when trains cross it:
It's perfectly safe, but all that flexing accelerates the aging of the bridge and makes it more expensive to maintain. Each pair of tracks on that bridge was closed for several years back in the 90s for repair/retrofitting work to try and address this. And because for the first five decades of the bridge's history it had trains going over its north side far more often than its south side, it to this day has a slight permanent northward lean.
So yes, you
can run trains across a suspension bridge, but it is generally not a desirable design for railroad bridges because of how flexible it is. Suspension bridges are great for evenly distributed loads. Concentrated loans make them do what you see in the video above.
Quote from: Duke87 on April 05, 2017, 08:15:49 PM
Quote from: MrDisco99 on April 05, 2017, 01:29:02 PM
Quote from: cpzilliacus on April 05, 2017, 02:06:18 AM
Also, if four stay cable towers are used (instead of two), the resulting bridge is stiff enough to carry railroad tracks if desired. Suspension bridges do not generally carry railroads because by their nature, they are rather flexible.
The Manhattan, Williamsburg, and Ben Franklin bridges would beg to differ. Other countries have even bigger bridges that carry tracks like the Tsing Ma Bridge in Hong Kong and the Øresund Bridge between Denmark and Sweden
Not without problems, though. The Manhattan Bridge flexes visibly when trains cross it:
It's perfectly safe, but all that flexing accelerates the aging of the bridge and makes it more expensive to maintain. Each pair of tracks on that bridge was closed for several years back in the 90s for repair/retrofitting work to try and address this. And because for the first five decades of the bridge's history it had trains going over its north side far more often than its south side, it to this day has a slight permanent northward lean.
So yes, you can run trains across a suspension bridge, but it is generally not a desirable design for railroad bridges because of how flexible it is. Suspension bridges are great for evenly distributed loads. Concentrated loans make them do what you see in the video above.
I wonder how much the ben franklin bridge flexes
I can't recall ever seeing it flex watching a train go by.
Quote from: jeffandnicole on April 09, 2017, 10:02:05 PM
I can't recall ever seeing it flex watching a train go by.
Oh, it does. I was watching it when we had an office in the building just to the south and you could definitely notice the train passing. I'd have to see a similar video to compare, though. But seeing a suspension bridge flex within its design tolerance doesn't squick me out. What do I know, I'm just a civil engineer.
Quote from: Alps on April 09, 2017, 11:21:38 PM
But seeing a suspension bridge flex within its design tolerance doesn't squick me out. What do I know, I'm just a civil engineer.
"Squick"? A civil engineering term?
Wikipedia article on the Manhattan Bridge is an interesting read about the effects of a series of train tracks on the structure, and what eventually happens if politicians overrule engineers' concerns about the need for repairs. Apparently loading the bridge such that one side dropped to 3 feet lower than the other side severely damaged the structure.
And now back to Bayonne...
Quote from: davewiecking on April 09, 2017, 11:48:21 PM
Quote from: Alps on April 09, 2017, 11:21:38 PM
But seeing a suspension bridge flex within its design tolerance doesn't squick me out. What do I know, I'm just a civil engineer.
"Squick"? A civil engineering term?
No, it's just a word that's rarely used unless you read TV Tropes, in which case it's used all the time.
Quote from: Alps on April 09, 2017, 11:21:38 PM
Quote from: jeffandnicole on April 09, 2017, 10:02:05 PM
I can't recall ever seeing it flex watching a train go by.
Oh, it does. I was watching it when we had an office in the building just to the south and you could definitely notice the train passing. I'd have to see a similar video to compare, though. But seeing a suspension bridge flex within its design tolerance doesn't squick me out. What do I know, I'm just a civil engineer.
I'm thinking of when I would go to the Camden Riversharks games and watching the train go by...and the traffic (and occasionally, I'd watch the game). I'm trying to recall any movement on the bridge, which I never recall seeing.
Taking a walk on the Walt Whitman one time when we were stuck in traffic due to an accident, that one I felt shake as the opposing traffic flew by. There was no mistaking that movement. But to the naked eye, I couldn't see the bridge itself move.
It's done now.
https://newyork.cbslocal.com/2019/02/11/four-lane-span-of-bayonne-bridge-opens-to-traffic/