How do you do the transformed Moment of Inertia of masonry sections?

[EngineerGeneral]

When calculate masonry combined compression and flexure,

fm = P/At + M/St

One needs to calculate the transformed moment of inertia to get St.

What is the formula for It?

 

[Lion06]

You can get It from any strength of materials book. I wouldn't mess with that, though. Just create an interaction diagram like you would for concrete. No need to calc It except for deflections (and even then you would use Itc, not It)