Steelwork into masonary

[Bickerton, Roderic K (SELEX) (UK)]

Burying steelwork in masonry is fundamentally very dodgy.
There is a lousy thermal miss match causing differential expansion
problems.
Steel corrodes and expands disastrously if its protection fails.
Protection is virtually impossible when a beam is buried in permeable
stonework that contains a cocktail of chemicals which can etch away and
destroy even galvanising, given time.

Loaded steel flexes under a moving load, even with large safety factors,
stonework will not flex much, it just cracks up.
(When behind a lorry have you ever noticed the deflection in a flat bed
trailer supported by a pair of 300mm RSJ's)


Very careful design based on an analysis of the stonework and its
properties can guarantee a long useful life, although possibly not in
all towers.

This is expensive and does not happen in most cases.

Solutions are expensive. A tower leaking water and acid from its
stonework could need large frame mounting pads cast from an impervious
cement and designed to give all round access to steelwork and drain any
free water away from the steel.
Where there is space, and the tower has an inside sill, rot proofed
timber wall plates may help. In a very wet tower timber is likely to
provide a longer life, although the inevitable tie rods and other metal
fixings will need to be made from a low corrosion material.

All to much trouble so we see disasters like Cury.
The frame looks clean red paint, but some of the steel beam ends have
completely failed. As things stand this fine Simpson 6 are unlikely to
sound again, although 10 years newer than our back 8 at Watford.
I fear that the next 100 years will see an ever escalating series of
steel frame support failures.


Rod






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