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Re: Poor Mojave............etc
Author: jst3751
Date: 10-05-2015 - 08:55
mook Wrote:
-------------------------------------------------------
>
> - 1994 demonstrated that the upgrades weren't
> enough, or that some structures were still waiting
> for them (does cost money, which comes in drips
> and drabs not large chunks), though unlike in 1971
> nothing fell on the railroad in the 14/5/210/405
> interchange area. Hopefully, when 14/5 was put
> back together (again), some further upgrades were
> done.
>
In my understanding, the biggest thing learned in the 94 quake (and to a lesser extent the 89 quake in Oakland) was horizontal movement and stress. Columns were torn apart as opposed to breaking by crushing force. Since then, all concrete columns now have a rebar cage in addition to the rebar within the column itself. Many existing bridge columns were "retrofitted" by building a steel cage around the column on the outside. They also "tied" the bridge plates to each and to the columns. Before that, many bridge plates were simply layed on the columns using pins.
-------------------------------------------------------
>
> - 1994 demonstrated that the upgrades weren't
> enough, or that some structures were still waiting
> for them (does cost money, which comes in drips
> and drabs not large chunks), though unlike in 1971
> nothing fell on the railroad in the 14/5/210/405
> interchange area. Hopefully, when 14/5 was put
> back together (again), some further upgrades were
> done.
>
In my understanding, the biggest thing learned in the 94 quake (and to a lesser extent the 89 quake in Oakland) was horizontal movement and stress. Columns were torn apart as opposed to breaking by crushing force. Since then, all concrete columns now have a rebar cage in addition to the rebar within the column itself. Many existing bridge columns were "retrofitted" by building a steel cage around the column on the outside. They also "tied" the bridge plates to each and to the columns. Before that, many bridge plates were simply layed on the columns using pins.
