Wood Beam Compression-Side End Notch Shear (NDS 3.4.3.2)
The shear capacity of a beam notched on the COMPRESSION face at the end.
Example
You enter
- Adjusted shear value Fv' (psi) 180
- Breadth b (in) 3.5
- Full depth d (in) 11.25
- Net depth at notch dn (in) 9.25
- Notch distance from inner edge of support e (in) 3
- Applied end shear V (lb, 0 to skip) 2000
You get
- Effective depth de (NDS 3.4-5) 10.60 in
- Compression-side allowable Vr' 4453 lb
- Same notch, tension side (for contrast) 2626 lb
- Demand / capacity 0.45
Details, formula, and sources
a completely different, far gentler rule than a tension-side notch. 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.
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.
The compression-side end-notch rule is stated in NDS 3.4.3.2, published free read-only by AWC at awc.org; the arithmetic is public.
Estimate. AHJ and licensed professional govern.
Field names used by the API: fv_prime_psi, b_in, d_in, dn_in, e_in, v_applied_lb, de_in, vr_lb, vr_tension_lb, dcr
- Effective depth de = d - ((d - dn)/dn) e grows back to the full d as the notch moves toward the support; e is capped at dn (dn governs beyond)NDS 3.4.3.2(e) Eq 3.4-5
- Compression vs tension the compression-side notch keeps far more shear than the tension-side (dn/d)^2 rule for the same net depthNDS 3.4.3.2
- Fv' user-supplied Fv' is the reference shear value times every applicable factor; the reference and factors come from the NDS SupplementNDS Supplement