Parks Department: Greenway Bridge Rehab Depends on Amtrak Schedule

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We have a few bits of news on the upcoming closure and rehab of the bike-ped bridge that connects the Hudson River Greenway to Washington Heights and the George Washington Bridge.

The bridge is a crucial car-free link for commuters and other users, but Northern Manhattan parks administrator Jennifer Hoppa tells us that the Parks Department does not have user counts specific to the bridge itself.

Also, though the bridge is owned by Parks, the city will have to access Amtrak property to do the work. It is not yet clear how long the project will take — discussions among members of Community Board 12 reportedly suggested a time frame of 18 months to two years — but Hoppa says construction must be coordinated to minimize Amtrak service disruptions.

The city and Amtrak are still in talks regarding bridge design and construction logistics, according to Hoppa. The project start date and alternate route for bridge users are still to be determined.

The new bridge is one of several PlaNYC improvements coming to Washington Heights and Inwood.

  • Anonymous

    It took four years to build the George Washington Bridge (with 1920’s technology!), and it may take two years to fix this tiny pedestrian/bike bridge over land. Can some engineer explain to me how the scaling of construction time for bridges works?

  • Ian Turner

    qrt145: My guess is that it takes two years of time because you have 2-3 employees working 4 hour shifts and spending half their time setting up and breaking down. Don’t worry, though, we’ll pay them for a full 8 hours of work.

    Also, 55 people died during the construction of the GW bridge. Safety expectations are very different now.

  • JamesR

    Wouldn’t it be sad if this induced Upper Manhattan and Northwest Bronx bike commuters into driving to work? The section of Broadway that you’re forced onto is sketchy enough that it’s almost the better option at certain hours of the day. 

    Parks must find a way to do better than this. 

  • I think qrt has the more accurate outlook on this. This is a bridge that could be done easily in 6 months in the winter if the political will was there. But in order to save 20% on the budget they’ll stretch the timeframe to 300%-400%. This is every construction project in NYC lately. Ask the people on the East Side who keep hearing ridiculously that a tunnel boring project under 2nd Avenue is going to take 8-10 years to complete (for revenue service) when half the existing city’s subway was done in that time with 1930’s technology.  It’s bad public policy. Ask Cuomo why he’ll spend $6 billion (that he doesn’t have) on a TZB replacement but 100 $6mil bridges have to wait forever in line for fixes.

    (BTW this bridge should have been taken care of, one way or another, years ago. The thing has gaping holes in it. It’s in horrible condition. The sick thing is that we’re only talking now about a solution.)

  • KillMoto

    The bridge can be built in 2 weeks in China, shipped over here in 3 weeks, and craned into place in a day. 

  • Guest

    Isn’t there a very good alternative just south of the GWB?

  • Miles Bader

    @brianvan:disqus Hmm, given that the SAS is 4-5 times more expensive, per mile, than equivalent construction in other countries (even those with very high costs and difficult ), I’m not sure cost-cutting is the problem there…

    [Or would construction on a more aggressive schedule make it 10 times more expensive than other countries?]

  • @google-9ed3368a6439fa92efd353af4436290d:disqus 

    Well, yes, there’s always that. It can’t be explained away by the differential in average salaries or materials cost, either. I would suggest that these construction bids demand scrutiny, but I wouldn’t hold my breath waiting for that to happen. (And we must have such a terrible economy if people feel it necessary to steal THAT much from the public trough. We really are a third world country, aren’t we?)

    As for an alternate path on the south side of the bridge: as far as I’m aware, there’s a “path” but it is an extended series of staircases that barely connects with the road network. The next entry to the river path south of the 170’s is at 158th Street. I would be happy to be incorrect here, though, but I’ve never discovered a rideable ramp on the south side of the bridge down to the waterfront.

  • Bridges-R-Us

    KillMoto: your 1-day replacement time estimate is generous.

    is but one of many sources of pre-built (in the US) truss bridges.

    Of course once the existing bridge is removed, it may become apparent that there’s need for work on the one or both abutments, but 18 – 24 months is absurd.

  • Joe R.

    @c44dc01f8107c1b33104b538f33b734d:disqus I agree 100% with your idea. Better yet, have workers from China come and and build our infrastructure projects, including finishing up the 2nd Avenue subway (I’ll bet they could finish from Hanover Square to the Bronx in a few years). Things will get done at 10% of the cost and 10% of the time. Like everyone else posting here, I’m just so sick and tired of every infrastructure project taking forever and costing a fortune. If anything, with the technology available today, we should be able to build things faster and cheaper than 50 years ago.

  • Anonymous

    Fiber Reinforced Plastic Bridge – The Graduate was right – the future is Plastic.

    FRP bridges are now state of the art, not bleeding edge, and they are ready for prime time.
    The biggest advantage is that it is much lighter than steel/concrete/wood; second that FRP has a very long useful life without rust, rot, or corrosion.  FRP  can be pre-fabricated – here in the USA, and not China; being lighter, it’s much easier to ship to the site.

    Biggest factor at this location, is that the FRP bridge is so much lighter than steel ect. that it can be swung into place by one crane, complete.  The path access to the bridge site is very tight so a not too big crane would be needed.  Staging the bridge would also be tough, possibly on the path, or on a rail car below. But being light, it can be swung in place quickly.  Worse case, or maybe best case, a FRP bridge this size can be brought in by helicopter in one pass.  This has been done at multiple difficult locations.

    The bridge can be set in place with deck and railings already installed – saves weeks of setup time.

    The only unknown is what is the condition of the abutment – the concrete supports – under each end of the bridge.  If these have to be totally rebuilt, traditionally, it involves weeks to months, of cutting and replacing.  Factor in protecting the Amtrak service below and it can stretch out forever.  A few cubic feet and stop for the next train.

    The design engineers have to be creative here.  They have to see if they can prefabricate a support structure that can be fastened in place overnight.  Or they have to try to drill down with new supports behind the current wall in a way that won’t drop anything on the trains.  Combine this creative abutment with the lighter weight FRP bridge deck, and possibly Amtrak impacts can be held to a very small window.

    Unfortunately, the Parks Department does not have a good track record in hiring and directing this sort of creative design team.  Same old boiler plate – literally – gets built.

    Side point – pun intended – is that a prefab temporary bridge could be laid across the Amtrak cut along side the current bridge – with side paths swinging around the construction zone.  Yes, a few trees may have to be cut for the side bridge, but unless there is a safe alternative, or a FRP bridge can be flown in and installed in a day, this may be the only viable detour.

  • Anonymous

    Brian Van Nieuwenhoven wonders why the 1904 subway could be built rapidly and cheaply with cut and cover while 2nd Ave tunneling seems slow and expensive.
    Utilities.  There were very few utilities under the streets in 1904, and what there was, was simple to move aside.

    Today, besides the basic water, gas and sewer pipes, there are wires.  Lots and lots of wires, plus fiber optics, plus steam lines.  The electrical system is fairly complex, but the real budget killer is the telephone/communication network.  Every phone and fiber line has to be individually protected from end to end. No wire can be cut, and none can be crossed.  Junction points have thousands of connections, and it’s all hand work to rewire.  None of this existed in 1904.  It was dig a hole, support the pipes as you dig, put in walls and the roof and start running trains.  Can’t do that today.

    Even in the 1970’s, the digging was easier.  There are complete subway tunnels north of 96th to 120th St already dug as cut and cover under 2nd Ave.  The plan was to do the same south of 96th St, but factoring in the utility moves, deep tunneling was much less disruptive and cheaper.  Really. 

    All that mess on 2nd Ave now?  Almost all is just for the new station access.  Imagine if every inch of subway had to be cut down from the roadway?  Most of 2nd Ave did not have to be cut for the subway tunnels, just for the station access.  And for most of that distance, the utilities did not have to be disturbed either.

    Want to point to the real villain that delayed 2nd Ave and cost us money?
    Try Rudi Giuliani  and his favorite governor.  Between them they held back the budget for 2nd Ave in order to push East Side Access ahead.  2nd Ave subway should have been in construction right after the civil work on the 63rd St Connection was wrapping up.  The Transit Authority had an experienced management team in place to switch from LIC Queens to 2nd Ave.  But Giuliani delayed the design work and EIS, and more than 5 years was lost getting started.  Any delay increases costs because materials and labor prices increase over time.  It increases costs because a whole new management team had to be created, and we all lose because we wait 5 or more years extra before we can benefit from the project.

  • Guest

    @Brownstone2:disqus – good list.  Life safety and ADA accessibility also increase costs above original construction.  This results in very high expenses for mechanical systems as well as property acquisition.

    In 1904, you put a few grates in the sidewalk and dropped some stairs on the sidewalk, and called it a day.  But today, to protect passengers from smoke in the event of a major fire, more extensive smoke purge systems are required.  Anybody notice the large ventilation buildings for the Second Avenue Subway? 

  • Zulu

    Yes you can pre fab a bridge, fly it over with a helicopter, inch it over from one side or the other but you are all missing one huge and obvious issue: railroad tracks. AMTRAK will never allow work on the right of way without the use of foul time or track outage. These are slots of time in which AMTRAK restricts the passage of trains on the track for purposes of construction crews. NYC Parks has to ask for these outages and AMTRAK has to give them out. Given that these tracks are used daily it becomes a very complex and slow operation dictated by train schedules.

  • Ryan

    Amtrak could run out of Grand Central for a Month like they used to and they could get a lot of repairs done.

  • Zulu

    As much as I would like that bridge to be repaired in a couple months instead of two years, it is unreasonable to expect AMTRAK to switch their operations for a “lowly” pedestrian bridge.

  • Ryan

    I bet there are a lot of other repairs they would do during those months that they’ve been holding off on for a while. But I agree…it was completely hypothetical.

  • Anonymous

     @be5555f82ee16ba420bee2ec0181a69b:disqus A helicopter would drop the bridge directly on its abutments, it would not be landed and then slid. 
    If they wanted to slide it, they could drive it in by truck.  If they can get the right crane in place, it can be swung in one move to its footings from a truck.  Trains would be stopped for under an hour.  It’s been done before.  That’s whole point in building the bridge in lightweight plastic.  Quick easy installation.

    As said below, the abutments have to be restored to a state of good repair first.  This could be the show stopper unless designed and managed carefully.  Since there are two tracks in the cut, running single track operation would work, while the crew is on the opposite rock face.  Building a construction shed over the single running track would protect the trains.
    This is about fixing a railroad, not rocket science.

  • Malcolm_in_WaHi

    How about say 1 month of inspection followed by 0 months of construction. I live 4 blocks from this bridge and bike over it from time to time. What evidence is there that it is unsound (for light pedestrian/bike traffic)?

    Is this a bridge that needs fixing or a contractor that needs a job getting together with a pol who needs an “accomplishment” to point to?

  • Spansaver

    The thought of replacing a historic bridge that could be cheaply rehabilitated for pedestrian traffic with a bridge made out of… PLASTIC! Are you guys serious!! Quit wasting taxpayers dollars so that the corrupt engineers, contractors and politicians can pad their wallets. I am a bridge inspector that specializes in old truss bridges and these structures are more than adequate to carry pedestrian traffic…and a whole lot more interesting to look at than a hunk of plastic. They just don’t bring as much money to the greedy powers that be!

  • The view is awesome but the bridge looks a bit narrow…

  • redbike

    Here’s a link reporting (with a pic) how a similar span connecting Liberty State Park and Jersey City has been replaced post-Sandy:

    Salient points include: the replacement span is pre-fab; and, elapsed time from the destruction through replacement was seven months, not two years.

    Considering that the work to replace the span bridging the rail cut north of the GWB is planned, I’d like an explanation why closure of this pedpath segment can’t be limited to a few days to remove the old span, repair the abutments if necessary, and install a new pre-fab span.