how about floating roads instead of bridges?

Discussion in 'Boat Design' started by Squidly-Diddly, Oct 20, 2019.

  1. Squidly-Diddly
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    Squidly-Diddly Senior Member

    There is some talk of adding another bridge across SF Bay (location to be determined).

    As long as it doesn't cross path of big ships that anchor in region just south of Bay Bridge, why not pontoon bridge? Restrict it to everything except the super-heavy trucks if needed. Have one or two sections with about 40' vertical clearance for most boats, and ability to swing open a 100' wide section semi-regular, like certain early morning hours on weekends when other bridge traffic is light and more people will be out sail boating.

    Sure it might need more ongoing maintenance man-hours, but those are actual "local jobs" (VS Bay Bridge replacement that got outsourced to China).

    I'm sure a floating bridge could be built lot faster and cheaper than real bridge. Its all already been long pre-engineered by every large army in the world to be able to carry 50+ ton tanks with steel treads.

    Probably get past Environmental Impact better than real bridge. Its really just like a bunch of boats dropping anchor, and that is already fully legal, so the NIMBYs can be told to STFU. If anything it would be more habitat.

    As noted, on the weekends traffic would be light, so maybe it could become a dedicated boat launch and fishing pier on non-work days.
     
  2. rwatson
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    rwatson Senior Member

    Used to have one of those.

    This one is next to the Pylon Bridge that replaced it.
    It was a pain in the *** when boats (even small ones) required to pass through the navigation gap and stopped all the traffic.

    FloatingBridge.png
    Hobart's Floating Bridge http://www.visithobartaustralia.com.au/floating-bridge.html

    Then, after a few years of operation, the pylon bridge was knocked down by a ship.
    And even now, all traffic stops when a decent-sized ship has to go through, but not for every yacht and motorboat at least.
    The maintenance was really, really high on the floating bridge towards the end of its life

    Oh yes, it was a real pain in winds
    . FloatingWeather.jpg
     
  3. ondarvr
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    ondarvr Senior Member

    Seattle has two large ones over Lake Washington, they replaced one bridge a while back, they sold some of the used sections to be used as floating docks and resorts in remote parts of Canada and Alaska.
     
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  4. Squidly-Diddly
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    Squidly-Diddly Senior Member

    looks fine, really. Nice to see the floating arch is all sorted out and able to let large ships pass. I lived on Island of Alameda in SF Bay that has draw bridges that stop traffic.
    We don't allow any real weather in CA. Redwood City and Oakland (on either side of bay) both lay various claims to "best weather in USA, by Govt test" etc.
    Built in 1938, and stuff has come long way since. "The maintenance was really, really high on the floating bridge towards the end of its life" Yeah, but now we got epoxy paint and have been anchoring massive oil platforms in deep stormy oceans for decades.

    Now that I've seen the floating arch, I think SF Bay could use 2 new floating bridges:

    1) between Bay Bridge and San Mateo
    2) between San Mateo and Dumbarton

    PS-we don't allow weather, but we do have earthquakes, but floating bridges not bothered by quakes. SF Bay has never had a tsunami, due to chicken throat (but deep) opening.
     
  5. Squidly-Diddly
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    Squidly-Diddly Senior Member

    thats what I'm talking about. modular and reusable. If they dragged to remote Canada and Alaska AFTER its regular service life it must be pretty good stuff.
     
  6. jehardiman
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    jehardiman Senior Member

    You left out the Hood Canal Bridge. Important to note, is of those three floating bridges, two of them have previously sank.
    Realistically, there are only a few scenarios where the need and the environment make a floating bridge the engineering answer of choice.
     
  7. gonzo
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    gonzo Senior Member

    Driving over a floating bridge can be done at moderate to slow speeds. However, the bridge will roll, pitch and heave like a boat does. It is much harder to drive over than a standard bridge. Another challenge is to keep the approaches, which need to adjust for water level, at a moderate slope. Otherwise, it can be really hazardous. The maintenance of the hinges, anchors, chains and other attachment points is very high compared to a standard bridge also. Further, required elements like safety rails and handrails are an engineering challenge to achieve code compliance. I can only see the application for the military when they will be used for short periods of time and there is no code compliance.
     
  8. ondarvr
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    ondarvr Senior Member

    The Hood Canal Bridge sank in 1979 in a storm with 120 mph gusts. It was built in 1961 and wasn’t engineered well enough to withstand that type of wind. It was rebuilt to a much higher standard.

    The Interstate 90 bridge sank while it was closed for renovations, it was reported that hatches were left open and pumps weren’t working.
    It had been built in 1940.

    There was already a newer floating bridge right next to it carrying the traffic.

    Sections from the old bridge were the ones sold.
     
  9. ondarvr
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    ondarvr Senior Member

    These aren’t small bridges like used by the military.

    Lacey V. Murrow Memorial Bridge - Wikipedia https://en.m.wikipedia.org/wiki/Lacey_V._Murrow_Memorial_Bridge
     
  10. W9GFO
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    W9GFO Senior Member

    We've got three floating bridges around here, two on Lake Washington (fresh water) and one in Hood Canal. I have felt more movement on regular bridges than these three floating ones.

    The Hood Canal floating bring is unique in that it must cope with 10+ ft tides. I think floating bridges are only practical over large spans of deep water - in relatively protected areas.
     
  11. Squidly-Diddly
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    Squidly-Diddly Senior Member

    Yeah, but issue with SF Bay rush hour traffic jams is they ARE slow, so "moderate" would be a huge improvement. Main issue is one wreck or even stall instantly adds several hours of wasted time and gas for about a million people. Approaches to South SF Bay are completely flat, like Tidal Mud Flats flat for near a mile on both sides. Real issue would be "has anyone ever put a 'floating' bridge on MUD FLATS?" Mud Flats can be a challenge, especially at low tide when I think even speical outboard "mud buddy" rigs would get stuck. I have seen Rescue Teams training with hovercraft at Palo Alto baylands park. South SF Bay doesn't get much swells, but can be choppy. Several spots attract Wind Surfers. Unlike a Military Bridge, if needed, it would be perfectly OK to widen the pontoons out a few yards on either side if that was needed to mitigate rolling.
    On going maintenance is an issue, but consider the massive cost assplosion of the recent Bay Bridge remodel. bay bridge cost overruns - Google Search https://www.google.com/search?client=firefox-b-1-d&q=bay+bridge+cost+overruns "from 250 million to 6.5 BILLION" I hear its actually much higher, when stuff like added interest etc is included. Bonus: its all totally defective from Day One, and due to "all or nothing" nature of such structures, there is no way to fix it. :) Everyone is basically resigned to hoping another big quake doesn't hit before all the guilty parties can hide the money. Bad steel, rust, leaks, and even microbes now. Steel Strength Raises Questions about Bay Bridge Safety https://www.courthousenews.com/steel-strength-raises-questions-about-bay-bridge-safety/

    The Mystery of the Brand-New Bay Bridge's Corroded Steel https://www.wired.com/2015/06/mystery-brand-new-bay-bridges-corroded-steel/

    Microbes reportedly corroding submerged Bay Bridge welds https://www.sfgate.com/bayarea/article/Caltrans-bay-bridge-microorganisms-corrosion-12528952.php

    In contrast, if you build a Floating Bridge, and something needs changed, there would be literally thousands of qualified contractors ready and able to do the job and very competitive rates, and there would be several ways to go about it, and no matter how bad anyone fails someone else could fix it.

    I've recently done a bunch of land-lubber construction work installing ADA etc code handrails etc. Even with a gaggle of no-nothing inspectors and "project engineers" to help, its really not a challenge or even expense. Little drilling, welding, grinding and painting and GTG for next 30-40yrs like the stuff we're replacing/upgrading (in SF Bay water side environment).

    In SF Bay Area, the real challenge is always the NIMBYs. SOMEONE is gonna wanna object if the expressway near their house is scheduled to take on some new traffic, and someone might even object if relieving brutal rush hour traffic jams diverts traffic away from their business.
     
    Last edited: Oct 21, 2019
  12. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I'd also be interested in a Floating Bridge that has a section that, instead of raising up, swings away to allow ships of unlimited size to pass.
    Sure, the towers allow for simple push button operation, once engineered and built, but it seems like a few cables and winches could be used to open and close a section. Little more operator skill and training, but much less initial investment, as well as less risk of things going horribly wrong. Its assumed any Floating Bridge already has built in ability to get built, which means adding sections, so it would just be one or two sections with more active connections. Yeah, might take longer to open and close.
     
  13. W9GFO
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    W9GFO Senior Member

    The Hood Canal bridge does not raise up like a drawbridge, instead it raises a long section of roadway vertically, then retracts the rest of the roadway underneath to form the passage. When both sides retract this makes 600 ft of space for ships to pass through.

    Video of retraction
     
  14. gonzo
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    gonzo Senior Member

    There aren't thousands of qualified contractors to work on floating bridges. Bridge contractors need to be certified and vetted, which is a lengthy and convoluted process. Have you ever towed barges? It is not something that operators with little skill can do. Even floating docks can be a challenge with wind and current.
     

  15. ondarvr
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    ondarvr Senior Member

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