# D for a masonry shear wall



## hank89 (Apr 3, 2012)

What are you guys using for d or d sub v for the shear stress of a masonry wall. fv = V/(b*d sub v)?

SERM and 2006 structural seismic uses the total wall width. (d sub v)

Susan Frey and an old NCEES Structural II practice exam use d (depth to reinforcing)

Thanks!


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## McEngr (Apr 3, 2012)

Trust Sue Frey


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## dakota_79 (Apr 3, 2012)

Yeah, based on the MSJC commentary to section 2.3.5, I agree with the latter. Although shear is resisted either by masonry or by steel, not both in combination, the reminder that a wall subject to in-plane flexure assumes the tension side is cracked. So even when ignoring the horiz bars for shear strength, the effective depth should still be closely approximated by depth of reinforcement, since that is approximately the depth between tension cracks where masonry is available to resist the shear.

Additionally, note that the MSJC explicitly uses the d term, not dv, in the shear stress calc (even though it does define dv in the notation section).

Either way, the difference is fairly minimal unless the wall is not long, so I'd err on the side of being slightly conservative and using the reinforcement depth.


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## hank89 (Apr 3, 2012)

Thanks!


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## CRNewsom (Apr 5, 2012)

McEngr said:


> Trust Sue Frey


This may very well be the best advice ever given in reference to masonry design. I took the Kaplan review course and I am absolutely in awe of Sue Frey. If I were anywhere near where she teaches, I would take every class she taught.


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