Wood Beam Compression-Side End Notch Shear (NDS 3.4.3.2)
The other half of the notch rule the tension-side shear tile leaves out, and it is a completely different, far gentler rule: a notch on the COMPRESSION face at the end. NDS 3.4.3.2(e) Eq 3.4-5 uses an effective depth de = d - ((d - dn)/dn) e that grows back toward the full depth as the notch e moves toward the support, so Vr' = (2/3) Fv' b de. At e = 0 (notch right at the bearing) de = d and there is NO reduction at all; the same 4x12 notched 2 in and 3 in from the support keeps 4,453 lb where a tension-side notch keeps only 2,626 lb - about 1.7x more. This is why, when a notch is unavoidable, the compression face is the place to put it. Enter e up to dn (beyond that the net depth dn governs). A design aid, not a substitute for the engineer of record.
Formula and source
de = d - ((d - dn)/dn) e (capped at dn for e >= dn); Vr' = (2/3) Fv' b de; tension-side contrast Vr' = (2/3) Fv' b dn (dn/d)^2; fv = 3V / (2 b de); dcr = V / Vr'.
NDS 3.4.3.2(e) compression-side end-notch rule (2018 Eq 3.4-5), by name; the adjusted shear value comes from the NDS Supplement.
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