calculating plastic modulus Z

[hippo11]

Can I do this without integrating? For a rectangular section, it's easy, bt^2/4, but for a tee section for instance, is there an easy way to do this?

And please don't tell me it's S * shape factor...

thanks

 

[Lion06]

It is easy, this has been covered before.
Find the PNA (plastic neutral axis). This is the axis about which there is an equal AREA of steel above and below.
Now find the centroid of the area above and below the PNA.
Now multiply the area of the steel above times the distance from the PNA to the centroid of the area above and add that to the product of the area below times the distance from the PNA to the centroid of the area below the PNA.
This will result in the area above OR below (which will be equal) times the distance between the two centroids.
That is Z.