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corrosion, was: Re: backyard/basement fallout shelter

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  • David
    ... Yes, indeed. Cathodic protection, to mitigate this, is a big deal. And not just for tankage, but pipelines and cabling as well. You deploy power supplies
    Message 1 of 5 , Aug 30, 2009
      > And as soon as the water pressure overcomes the surface tension of the
      > water, it will find its way to something metallic, and Mother Earth being
      > a Mother first and a Protector second, the process of corrosion will
      > begin.


      Yes, indeed. Cathodic protection, to mitigate this, is a big deal. And not
      just for tankage, but pipelines and cabling as well. You deploy power
      supplies and and sacrificial anodes, and send a guy out to tromp around
      measuring the voltage at every test station, and ....

      And where it gets interesting is when you have multiple cables/pipelines in
      a given area. See, what helps you hurts the others. There are semi-formal
      "cathodic protection councils" for a region that would meet to hash this
      all out...usually at a bar.
    • John Young
      I thought I was familiar with underground construction until I worked on a subway project some 200 feet below ground. What was eye-opening was how brute
      Message 2 of 5 , Aug 30, 2009
        I thought I was familiar with underground construction until I worked
        on a subway project some 200 feet below ground. What was eye-opening
        was how brute strength was used to overcome lighter weight design
        solutions. Again and again when I asked why not do something this
        way or that customarily used in relatively shallow underground
        construction, the engineers would laugh. That's not how we do
        it, they would say.

        Everything was solved by massive use of reinforced concrete with
        special mix designs: seismic, corrosion-resistance, moisture protection,
        electromagnetic protection, acoustic and vibration control, electrical
        arcing, you name it. More concrete, more reinforcing, more specialized
        mix designs.

        The main difference was in the far greater cost freedom for deep
        underground work than in shallower construction. Billions of dollars
        not millions or even hundred of millions.

        The argument for this approach was that these structures are not
        designed to deteriorate, be repaired or restored, or replaced. Instead,
        the design assumption was that these will be in place indefinitely,
        that repairs will be limited to the least possible amount if at all.

        And that forces working to cause deterioration or failure are so
        powerful that there should be almost no limit in design against them.

        Heh, for those of us accustomed to slaving under cost limitations,
        the tyranny of cost engineering which whacks away at the best of
        one's efforts, and having to accept that deterioration as a given to
        be passed on the next property owner or generation, this is strong
        medicine.

        These subway engineers, most of who had worked on underground
        projects for the military with very generous budgets for really
        demanding standards for durability, claimed it is no surprise to
        them that above ground and shallow underground structures
        deteriorate so fast and fail under fairly light natural disasters.
        It is not science or engineering that is lacking, it is the dominance
        of bean counters and profiteers who set and enforce building
        codes, safety standards and acceptable risks to the public.

        To be sure, anybody who has worked on a classified construction
        project will know what these gents are talking about. Commercial
        grade they are not: they don't fall down, float, sink, leak or come
        apart at the seams due to acts of God -- or man, unless a shrewd
        engineer sets off the biggest IED ever.
      • David
        ... And if you do screw up....it s there a long time... Earlier parts of the WMATA Red Line tunneling, the western leg under Rock Creek, suffer from continual
        Message 3 of 5 , Aug 30, 2009
          jya:

          > The argument for this approach was that these structures are not
          > designed to deteriorate, be repaired or restored, or replaced. Instead,
          > the design assumption was that these will be in place indefinitely,
          > that repairs will be limited to the least possible amount if at all.

          > And that forces working to cause deterioration or failure are so
          > powerful that there should be almost no limit in design against them.


          And if you do screw up....it's there a long time...

          Earlier parts of the WMATA Red Line tunneling, the western leg under Rock
          Creek, suffer from continual water infiltration from the water table. This
          takes a big toll on track equipment: rails, clips, switches, and the
          signaling equipment.

          Later construction uses a polyethylene lining outside the pour to limit the
          leakage.
        • jks19714
          Ahhh. Some of those could get pretty lively. I was always on the receiving end - I won t drink and never did (much) field work until things were really a
          Message 4 of 5 , Aug 31, 2009
            Ahhh. Some of those could get pretty lively. I was always on the receiving end - I won't drink and never did (much) field work until things were really a mess.

            Like neutrals on the power distribution getting "hot" enough with "sneak" currents that the induction tripped out all of the trunks to a CO (insufficient bonding on everyone's part and tons of electrolysis and defective grounds as a result), or the occasional "oops" when the neutral melted from the power flow.

            Almost every instance was incorrect use of grounds, isolation (bonding) or (*usually*) lack of maintenance. Everyone was (is) so busy looking up for the problem that they forget to look DOWN at the ground bonding.

            Since I began life as a chemist and once audited a course on corrosion (everyone needs a hobby) and spoke a familiar tongue (bilingual - power and telecom utility), I was frequently sought as a neutral (pun intended) party.

            Ever try to emplain to your employer's district manager how his fieldman's lack of attention to detail had blown out a grain elevator's telephones and his (my) company owned Bell (and the customer) a couple of grand? No neutral and a loose ground on a 3-phase 12 KV service drop is bad ju-ju. :-)

            The good news is that the district manager has retired, I'm still here and, 15 years later, the customer still remembers my name in a good way. They asked one of my (former) bosses "where I was" a few weeks ago.

            Utility work is never dull.

            john

            --- In coldwarcomms@yahoogroups.com, David <wb8foz@...> wrote:
            >
            > > And as soon as the water pressure overcomes the surface tension of the
            > > water, it will find its way to something metallic, and Mother Earth being
            > > a Mother first and a Protector second, the process of corrosion will
            > > begin.
            >
            >
            > Yes, indeed. Cathodic protection, to mitigate this, is a big deal. And not
            > just for tankage, but pipelines and cabling as well. You deploy power
            > supplies and and sacrificial anodes, and send a guy out to tromp around
            > measuring the voltage at every test station, and ....
            >
            > And where it gets interesting is when you have multiple cables/pipelines in
            > a given area. See, what helps you hurts the others. There are semi-formal
            > "cathodic protection councils" for a region that would meet to hash this
            > all out...usually at a bar.
            >
          • jks19714
            Hello. Some world -- I visit one of your websites at least once a day (although not from work!), although we have never met. I do make certain to have a
            Message 5 of 5 , Aug 31, 2009
              Hello. Some world -- I visit one of your websites at least once a day (although not from work!), although we have never met. I do make certain to have a fresh nitro patch on though -- the pictures of the PAL Recoder a few weeks ago nearly brought on "The Big One".

              This thread stimulated my interest (as do many of them) to rummage through some boxes at home looking for "buried treasure". I am still foraging, but came across another excellent, and in my case, long-forgotten book -- Underground Space Design by Sterling and Carmody.

              It is still in print according to the Amazon website (ISBN is 978-0471285489 for those of you who would like a good read), but as most highly specialized books, very expensive if bought new ($160!). I find a great deal of interesting material by dropping these books into my "wish list" and visiting my wish list to see "what is new", either new or used, and looking at the asking price. From there, it is a simple matter to delve deeper and decide if the price is less than or equal to the information's value to me.

              I gave it a quick browse last night and another factoid that popped out of my "bottomless pit of useless information" was the fact that U of Minnesota has a very impressive underground space as part of its' main campus. I had heard that long ago, but it didn't "click" until last night sometime.

              Google is a useful tool, but linking on the Internet is still TRIVIAL compared to the human brain. (and I'm a re-formed IBM 360-91 FORTRAN programmer, so I guess that kind of dates me) :-)

              Best regsrds,

              Another john


              --- In coldwarcomms@yahoogroups.com, John Young <jya@...> wrote:
              >
              > I thought I was familiar with underground construction until I worked
              > on a subway project some 200 feet below ground. What was eye-opening
              > was how brute strength was used to overcome lighter weight design
              > solutions. Again and again when I asked why not do something this
              > way or that customarily used in relatively shallow underground
              > construction, the engineers would laugh. That's not how we do
              > it, they would say.
              >
              > Everything was solved by massive use of reinforced concrete with
              > special mix designs: seismic, corrosion-resistance, moisture protection,
              > electromagnetic protection, acoustic and vibration control, electrical
              > arcing, you name it. More concrete, more reinforcing, more specialized
              > mix designs.
              >
              > The main difference was in the far greater cost freedom for deep
              > underground work than in shallower construction. Billions of dollars
              > not millions or even hundred of millions.
              >
              > The argument for this approach was that these structures are not
              > designed to deteriorate, be repaired or restored, or replaced. Instead,
              > the design assumption was that these will be in place indefinitely,
              > that repairs will be limited to the least possible amount if at all.
              >
              > And that forces working to cause deterioration or failure are so
              > powerful that there should be almost no limit in design against them.
              >
              > Heh, for those of us accustomed to slaving under cost limitations,
              > the tyranny of cost engineering which whacks away at the best of
              > one's efforts, and having to accept that deterioration as a given to
              > be passed on the next property owner or generation, this is strong
              > medicine.
              >
              > These subway engineers, most of who had worked on underground
              > projects for the military with very generous budgets for really
              > demanding standards for durability, claimed it is no surprise to
              > them that above ground and shallow underground structures
              > deteriorate so fast and fail under fairly light natural disasters.
              > It is not science or engineering that is lacking, it is the dominance
              > of bean counters and profiteers who set and enforce building
              > codes, safety standards and acceptable risks to the public.
              >
              > To be sure, anybody who has worked on a classified construction
              > project will know what these gents are talking about. Commercial
              > grade they are not: they don't fall down, float, sink, leak or come
              > apart at the seams due to acts of God -- or man, unless a shrewd
              > engineer sets off the biggest IED ever.
              >
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