some bay bridge construction time lapse videos

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4 Responses:

  1. mattyj2001 says:

    I'm no engineering nerd but this project amazes me. I still would like to know how the detached and scooted aside the old section of bridge.

    Here's an idea. When the bridge is finished and the start tearing down the old one, cut out little pieces of the scrap and sell them attached to a special edition DVD. I'd pay $100 for that.

    • dasht says:

      I only know what I get from TV but how they did it according to the reporting on KRON-4:

      They custom built two massive jacks - one for under the new section, one to get jacked up under the old. These jacks rest on teflon skids.

      The bridge architecture is naturally segmented although, from what I could tell, the road-bed itself was not. So they had to just detach the segment being removed and attach the new segment, but also do a bit of torch work cutting up rebar or some such on the road bed.

      Before detaching the old segment, because its removal would change the mechanical stresses on adjacent segments, they installed massive (bigger than you) C-clamps on some structural elements of adjacent segments. Yes, they clamped the bridge during this to make sure it didn't tear itself apart.

      Having detached the old segment, they lubed up the teflon skids with a few cases of dishwashing soap purchased (after a competitive price analysis) from a Costco. I think it was "Dove" brand soap they used but I could be wrong. I'm not sure whether or not they had to do an environmental impact report about the consequences of dumping a large quantity of dish soap so near the bay.

      Then they slid aside the old segment and got ready to slowly lower it to the ground for demolition and slid in the new segment to be attached.

      There was apparently a tiny but noteworthy chance that the old segment would, as it was slid aside, structurally fail and demolish itself, coming crashing to the ground. The engineer that was reporting that bit of trivia remarked that "If that happens, it will be a little embarrassing." Alas, it turns out we get the expected boring outcome that it will be lowered gently to the ground for demolition.

      And, yes, C.C. Myers Co. and CalTrans just seem to be obnoxiously competent at this kind of thing. They make it look easy.


    • dasht says:

      Oops.. sorry... I think I mis-spoke. The teflon skids, I gather from the vids, were atop rather than underneath the jacks.


  2. learath says:

    Impressive, most impressive.