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Wood columns: Parallam PSL can design on the published F_c with NDS 15.4 and footnote 13’s minimum eccentricity

ESR-1387 Table 1 footnote 13 gives a Parallam PSL 1.9E–2.2E column two routes: F_c for column applications (printed "500 psi", which we read as 2,500 psi), or the published 2,700 / 2,900 psi with NDS Chapter 15 and a minimum eccentricity e₂ = t/6 + 5L²/4608 across the narrow face. The column used only the first. Step 4 now offers the second as an option; the default is unchanged.

• Step 4 has a new choice for Parallam PSL 1.9E, 2.0E, 2.1E and 2.2E columns: F_c = 2,500 psi for column applications (the default, as before), or the published F_c with NDS 15.4 and the minimum eccentricity e₂. Picking the alternative shows e₂ with its numbers, and Steps 3, 4 and 5 say which route the design is on.
• On the alternative, every compression combination in Step 5 is checked with NDS 2024 Eq. 15.4-3 and 15.4-4, or Eq. 15.4-1 and 15.4-2 when the combination carries the lateral load: F_c′ on the published F_c, the e₂ moment across the narrow face resisted by the report’s face / plank F_b with its volume factor, and the side load’s own f_b, F_b′, F_cE and F_bE taken from the combined check. That interaction is what the Combined column, PASS / FAIL and the governing row read; the Step 4 factor matrix adds the face / plank C_V.
• Expect less capacity on the alternative: e₂ is at least t/6, so the eccentric bending stress is at least f_c itself. A 2.0E 5.25x9.25 post, 10 ft pinned, carrying 30,000 lb at C_D = 1.0: axial D/C 0.436 on 2,500 psi, Eq. 15.4-3 = 0.605 on the alternative. In the posts we checked it carried 54–70% of the axial load the 2,500 psi route allows. It is there for a design that should not rest on how the printed "500" is read.
• New book icons quote NDS 2024 §15.4.1 with its four equations and ESR-1387 Figure 2 (the eccentricity e₂), beside footnote 13.

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