CMU modulus of rupture fr

[braves25]

I am looking at deflection in a load bearing CMU wall. Two questions...One, I'm using Enecalc to design the walls and am given the option of using Ieff based on Mu @ Element or Icracked Full Height. Which should be used for deflection?

Second question, in determining my fr (modulus of rupture) there is a table in the ACI 530. If I have wind loads on a load bearing wall, will that be flexural tensile stress "normal to bed joints" or "parallel to bed joints"? Side question on this table....footnote reads that linear interpolation can be used between fully grouted and un-grouted CMU. However under the parallel to bed joints in running bond, the term "ungrouted and partially grouted" is used. What value is to be used for the "lower end" of the interpolation? Would I take the 125 for Portland cement type M or S for say CMU grouted at 48" o.c. and 200 for a solid grouted wall, and then interpolate for a 16" o.c grouted wall?

Thanks and have a great day.

 

[KootK]

I_cracked full height sounds unnecessarily conservative. I'd go with Ieff based on Mu at each element.

Flexural stress will be normal to the bed joints.

Because you're dealing with horizontal bending in the "parallel" case, anything less than fully grouted is effectively ungrouted. Interpolation is not appropriate.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.