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druxey

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Posts posted by druxey

  1. I quote a retired civil engineer (I hope she won't mind) who designed bridges world wide:

     

    I saw the newsreel of the bridge collapse in Baltimore yesterday. I had always felt that these American 'girder bridges' were too lightweight (part of America's planned obsolesce design practice in place in those years). But I was astonished to see how little protection was provided to the main supports. It's a no brainer - if you knock out a main support, the bridge collapses! And the main supports next to the navigation channel require special attention. On the Queensferry Bridge, which was downstream of the Forsyth Naval Dockyard where they build and maintain aircraft carriers, we carried out a study, including model simulation, of just such an event and designed the main pier caissons not to fail. Luckily, the Americans loved simple span construction for their approach viaducts and this acted as a fuse . . . [for] progressive collapse of the whole crossing! . . . .  what happened using 'the past is a foreign country' adage. It was opened in 1977! I was working on the Itchen Bridge then in a similar, but not as exposed, location upriver from the port of Southampton. Our River piers were protected by a massive caisson that extended out from the main columns by sufficient distance to guard against the superstructure hitting the bridge even as the hull of the vessel crumpled onto the caissons.

     

    So, there you have it.

     

     

  2. The bow ports were not armed: no space for working a gun! The were used as bridle ports for anchor handling. The vertical half-port lids illustrated were 'for example' and not drawn for all the other ports. You could not have a conventional lid as there was nothing but the rail above the port opening. There was no place to fit a hinge to! The advantage of these lids was that in a heavy sea you would not ship as much water over the decks as would happen with open ports.

  3. There are several suggested routes you might take. Try this first, though:

     

    If you used white glue, rubbing alcohol will soften it so that you can disassemble the planks and try again. Wetting the planks , you can re-shape them, then let them dry. The second time you now know what to look for and check on. It's always a learning process, no matter how long you've been building models!

     

    'Sea' what you can do! (groan)

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