Masonry Shear Wall Reinf. Ratio
Masonry Shear Wall Reinf. Ratio
(OP)
I'm designing a partially grouted masonry shear wall controlled by wind in SDC B. For the tension reinforcement resisting overturning (if the wall is subject to flexural tension), I'm taking the reinforcement ratio based on the NET area of the masonry. In this example, using an 8" block with grouted cells at 48" OC, the Anet = 41 in2/ft. So for a 8' long wall, the total Anet = 8' x 41in2/ft = 328 in2.
This is opposed to using the gross area which would be 8' x 12"/ft x 7.625" = 732 in2.
The masonry design textbook I'm using states that the reinf. ratio is As/b*d, so it uses the gross area, but this would only apply to a fully grouted masonry section, in my opinion. Section
Do you agree that Anet is the appropriate property to use for a shear wall reinforcement ratio? Are you aware of a good resource for the design of partially grouted shear walls? The NCMA tek manuals are great but do not seem to cover this specific topic.
This is opposed to using the gross area which would be 8' x 12"/ft x 7.625" = 732 in2.
The masonry design textbook I'm using states that the reinf. ratio is As/b*d, so it uses the gross area, but this would only apply to a fully grouted masonry section, in my opinion. Section
Do you agree that Anet is the appropriate property to use for a shear wall reinforcement ratio? Are you aware of a good resource for the design of partially grouted shear walls? The NCMA tek manuals are great but do not seem to cover this specific topic.






RE: Masonry Shear Wall Reinf. Ratio
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Masonry Shear Wall Reinf. Ratio
I did have a conversation about this topic with someone from TMS. It sounds like the correct way to do this is to calculate the area of the "U-shaped" compression block created by the fully grouted end cell and part of the face shells as determined by a stress/strain analysis. Not the easiest calculation to perform, especially when you have multiple layers of tension reinforcement. However, for design purposes I think you could conservatively assume that the area of masonry is only made up of the 2 face shells (like an ungrouted section) and calculate your masonry and steel stresses using the standard textbook method.
RE: Masonry Shear Wall Reinf. Ratio
I would never attempt to distinguish grouted from ungrouted in a shear wall, as I always insist on grouting them solid.
RE: Masonry Shear Wall Reinf. Ratio
RE: Masonry Shear Wall Reinf. Ratio