In message , at 12:41:12 on
Fri, 13 Jan 2012, Paul Scott remarked:
A steady seepage of salt water into the structure, built in the 1960s,
has weakened the structure, but engineers said it was now safe to take
light traffic.

But no, the cheaper but potentially very damaging rock salt was used,
and this is what has caused the problems with the pre-stressing cables
within the concrete structure.

Presumably this isn't the only structure of this type on the road
network though?

Are many more due to be found before long?

There were extensive repairs to the M6 viaduct in the Castle Bromwich
area a couple of years ago, and the A14 flyover across Huntingdon
station is widely regarded as being about to fall down. One of the
bridges at the M6/M1 junction was replaced very recently.

http://www.bbc.co.uk/news/uk-england-16460505

Not sure how many of these are salt related.
--
Roland Perry