Concrete Shear Strength
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The proper selection of the governing provision in LRFD can summarized by the following flow chart:
4-sided structure
Fill depth >= 2 feet
Use 5.14.5.3 for slabs
Use 5.8.3/5.7.3 for walls
If wall thickness >= 16” or member is in tension, use 5.8.3.4.2/5.7.3.4.2 (beta calculated using App. B5)
If wall thickness < 16”, use 5.8.3.4.1/5.7.3.4.1 (beta is a constant 2.0)
Fill depth < 2 feet
Use 5.8.3/5.7.3 for all members
If member thickness >= 16” or member is in tension, use 5.8.3.4.2/5.7.3.4.2 (beta calculated using App. B5)
If member thickness < 16”, use 5.8.3.4.1/5.7.3.4.1 (beta is a constant 2.0)
3-sided structure
Any fill depth
Use 5.8.3/5.7.3 for all members
If member thickness >= 16” or member is in tension, use 5.8.3.4.2/5.7.3.4.2 (beta calculated using App. B5)
If member thickness < 16”, use 5.8.3.4.1/5.7.3.4.1 (beta is a constant 2.0)
Note that the iterative beta method (beta calculated using Appendix B) is actually usable in all situations, regardless of the member thickness or location.
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