Wood Shear Wall Deflection (SDPWS Eq 4.3-1)

End-post bending 8vh^3/(EAb), panel shear plus nail slip vh/(1000 Ga) with the tabulated apparent stiffness, and anchorage rotation h da/b from the holdown slack -- in the equation's own calibrated units. A 10 x 8 ft wall at 400 plf on 4x4 posts deflects 0.47 in (0.40% drift), the shear and anchorage terms carrying nearly all of it; double the height and the h^3 bending term wakes up. Checked against the ASCE 7 story-drift limit -- the reason a tall narrow wall can pass strength and fail stiffness. A design aid, not a substitute for the engineer of record's stamped lateral design.

delta = 8 v h^3 / (E A b) + v h / (1000 Ga) + h da / b (unit-specific: v plf, h/b ft, E psi, A in^2, Ga kips/in, da/delta in).

The AWC SDPWS Equation 4.3-1 three-term shear-wall deflection (the apparent-shear-stiffness Ga linearization of the legacy four-term form), as compiled in the AWC/APA wood-frame shear-wall design guides, by name.

AWC SDPWS is viewable free of charge through AWC's online reader; the three-term equation and the Table 4.3A/4.3B Ga values are public.

Estimate. AHJ and licensed professional govern.

Field names used by the API: v_plf, h_ft, b_ft, e_psi, a_in2, ga_kin, da_in, bend_in, shear_in, anchor_in, delta_in

• Unit-specific calibrated equation Eq 4.3-1 is dimensionally non-homogeneous by construction (the leading 8 folds the ft-to-in conversion); enter the documented units exactly and do not rescaleAWC SDPWS Eq 4.3-1
• Tabulated Ga and measured da Ga comes from SDPWS Table 4.3A/4.3B for the sheathing and nailing; da is the holdown / anchorage elongation at the design shear from the manufacturer's dataAWC SDPWS Tables 4.3A/4.3B
• Drift limit separate the computed deflection is checked against the ASCE 7 allowable story drift (amplified by Cd/I where the strength-level force is used)ASCE 7 §12.12