Reinforced Masonry - Axial Load

[AlienMonkey]

I am studying for the SE exam to be taken next month and took a refresher course in Masonry.

The instructor when checking fa < Fa, used fa = P/An, or the axial load over the gross area of the column. Also (on another subject) when transforming steel in compression uses Ats = As(n-1).

The SERM examples when checking fa < Fa, use P/At, or the axial load over the transformed area of the column. When transforming steel in compression uses Ats = As(2n-1) to account for creep.

My question, which is correct?

 

[slickdeals]

I think either one is okay. I have had the question previously. Check the ARMY reference manual for masonry. They talk about using either n-1 or 2n-1

 

[slickdeals]

See page 24 in the army reference manual.
2n-1 is used for long term loading
n-1 is used for other than long term loading

http://www.army.mil/usapa/eng/DR_pubs/dr_a/pdf/tm5_809_3.pdf

 

[AlienMonkey]

Thanks, what about the axial stress calculation?

fa = P / An

or

fa = F/ At

 

[AlienMonkey]

I meant fa = P / At