Problem when using Contrete01

CMPeng · Post by **CMPeng** » Wed Sep 19, 2007 5:16 am

A 30 meters high pier with box section.
material is Contrete01 and Steel02,element is nonlinearBeamColumn,fiber section with contrete path and steel layer.

When I scaled up the PGA of one ground motion(even to 60g),
I found that the stress of steel is higher than its yield strength,
but the stress of contrete is always lower than its yield strength (even its strain is lager than the ultimate strain).

What's wrong with it?

silvia · Post by **silvia** » Wed Sep 19, 2007 7:42 am

isn't that the behavior you expect from your column?
it just means you don't have enough steel, or too much concrete!

CMPeng · Post by **CMPeng** » Wed Sep 19, 2007 5:18 pm

Firstly thanks for your help.

That isn't what I expect for my column. The ideal result is the concrete reach its yield strength before the steel yield, so through using more concrete I would get it, as you had mentioned .

There is another problem,however,I would like to emphasize. That is
how could the concrete stress was lower than its yield strength while the concrete strain had reached its ultimate strain !
How to explain this phenomenon ?

Thanks.

silvia · Post by **silvia** » Wed Sep 19, 2007 7:28 pm

look at the curve for the concrete material, it has residual stresses.