Re: Sydney Harbour Bridge Questions

["Ron BEST" <ronbest@bigpond.com>]

A structure such as a bridge can deflect an awful long way before it reaches
anything like its 'elastic limit', i.e. the point beyond which it will not
return to its original shape. Structures are usually made stronger than they
need to be to just to carry the load, so as to limit the amount of
deflection. Excessive deflection is disconcerting for users, and can cause
concrete slabs etc to crack. So, by closely monitoring the deflection of the
bridge under load, they would have known that it was nowhere near its
elastic limit, let alone its 'ultimate strength'.

BTW, I was once told that the bridge is NOT designed to simultaneously
withstand full "live" loading AND full wind loading. So, if there were a 200
km/h wind, they might have to close it for a while! (Although it is unlikely
that it will ever carry anything like its maximum designed live load, as
that assumed there would be four railway tracks.)
Rgds
Ron BEST
MarkBau1 wrote in message <19990316145553.01444.00000086@ng-ca1.aol.com>...
>What I want to know is how would the NSWGR have run its trains if the test
had
>failed! :-)
>
>Mark.
>
>
>Visit my train pic website at:
>http://home.earthlink.net/~markbau/
>
>