Example
A 4×4 Southern Pine #2 post, 9 ft tall, pinned at both ends (Ke = 1.2), carries 3000 lb dead plus 4000 lb live from deck beams. Check capacity per NDS 2024. CD = 1.0 for dead plus live.
How StructSuite solves this
StructSuite's free structural design software applies NDS 2024 §3.7: enter geometry (height, Ke), materials (species, grade), loads (D, L with CD). Computes FcE, Cp, allowable P. Checks bearing at support. 4×4 SP #2 at 9 ft pinned-pinned: typical capacity ~4–6 kip for D+L. Exceeding capacity: use 6×6 or reduce span.
Steps
- Step 1: Geometry & End Conditions
Design consideration: Height and Ke set slenderness Le/d. Pinned-pinned (Ke=1.2): deck post typical—base plate and beam both allow rotation. Fixed base (Ke=0.8): embedded in concrete. Le/d: 4×4 at 9 ft, Le=10.8, d=3.5 → Le/d=37. Buckling (Cp) controls when Le/d high.
In StructSuite: Open the Geometry section. In the Unbraced length (ft) input box enter the column height. Use the End condition dropdown to select the end fixity (Fixed-Fixed Ke=0.65; Pinned-Pinned Ke=1.2; Fixed-Free Ke=2.4 per NDS 2024 Table G1). Select the column size (e.g., 4×4, 6×6) from the dropdown or size table.
- Step 3: Material & Section
Design consideration: Southern Pine common Southeast; DF-L West; SPF North. #2 grade typical. PT for ground contact: CM~0.80–0.90; incising further reduces. Species affects Fc and Emin—Emin drives buckling. 4×4 vs 6×6: area 2.25×, capacity often 2.5× (buckling less critical for stockier section).
In StructSuite: Open the Materials section. Use the Product dropdown to select Sawn Lumber, LVL, or Glulam. In the Species dropdown select Douglas Fir-Larch, Hem-Fir, Southern Pine, Spruce-Pine-Fir, etc. In the Grade dropdown select #2, #1, Select Structural, etc. NDS 2024 Supplement Tables 4A–4D provide Fc and Emin.
- Step 2: Load Definition (ASCE 7-22 / NDS 2024)
Design consideration: 7 kip (3 D + 4 L) from deck beams. Tributary area: beam span × spacing. CD=1.0 for D+L. Covered deck: add Lr, S; CD=1.15–1.25. Wind uplift reduces axial; seismic adds moment—beam-column check.
In StructSuite: Open the Loads section. Click Add load case. In the Type dropdown select D, L, Lr, S, W, or E. In the Axial load (lb or kip) input box enter the load. CD = 1.6 for wind/earthquake per NDS Table 2.3.2. Add all applicable load cases. Include self-weight if significant.
- Step 5: Design Verification
Design consideration: FcE ∝ Emin/(Le/d)²—doubling Le/d quarters FcE. 4×4 at 9 ft: ~5–6 kip typical. 6×6: ~12–15 kip. Bearing at base: check Fc⊥ on mudsill or concrete. Overstressed: 6×6, or reduce beam span, or brace mid-height.
In StructSuite: Open the Design Verification section. StructSuite checks axial capacity per NDS 2024 Eq 3.7-1 (buckling) and Fc⊥ bearing. Review the D/C ratios. If overstressed, increase size in the Geometry section or reduce unbraced length. Slenderness ratio Le/d ≤ 50 for sawn lumber per NDS.
Live design (pre-filled)
The form below is the real StructSuite module with example data loaded. Display only—values cannot be changed.
Wood Column — Design per 2024 NDS
NDS 2024 Ch. 3 — Solid columns (3.6.2.1) per Section 3.7
Column unbraced length and end conditions per NDS 3.7. Ke affects buckling capacity.
Buckling modes |  |  |  |  |  |  |
| Select mode | ||||||
| Theoretical Ke value | 0.5 | 0.7 | 1.0 | 1.0 | 2.0 | 2.0 |
| Recommended design Ke when ideal conditions approximated | 0.65 | 0.80 | 1.2 | 1.0 | 2.10 | 2.4 |
| End condition code |  | Rotation fixed, translation fixed | ||||
 | Rotation free, translation fixed | |||||
 | Rotation fixed, translation free | |||||
 | Rotation free, translation free | |||||
Le = Ke × L. Use different Le for strong/weak axes if bracing differs.
L1: total unbraced height. L2: unbraced length above intermediate brace. Le = Ke × L.