"Tony Bryer" wrote in message
...
On Wed, 19 Dec 2007 10:21:31 -0000 Dave Baker wrote :
We are having work done on our house and it involves a big and heavy
steel beam to support most of the back of the house. It is probably
about 1000kg and 7m long (300mm x 300mm).

Firstly a quick calc shows it shouldn't weigh anything like that much.
No more than half a ton even if it's made from 1cm thick metal

300x300 UCs come in 7 rolling weights from 97 to 283kg/m so 1000kg is
perfectly possible.

Is this thing a complete box section then? I was assuming it was an I beam.
More calcs then. A complete box section at 30x30 cm and 1cm thick comes to
11,600 cc/metre and at an SG of 7.85 approx 91kg/m.

To weigh 283kg/m the material has to be 3.4cm thick. I can't even
contemplate a beam of that section in a domestic environment. You could
build a tower block on something like that surely.
--
Dave Baker
Puma Race Engines