SDPWS Footnote 2: Increase Shear Capacity for 15/32 Sheathing Conditions

Example

An 8×8 ft shear wall has 3/8 in. OSB with 8d common nails at 4 in. edge spacing. Studs are 16 in. o.c. and panels are applied with long dimension across studs. Wind load = 3,000 lb. SDPWS Footnote 2 permits using the 15/32 in. sheathing capacity (higher Vn). Check if the wall is adequate with Footnote 2 applied.

How StructSuite solves this

StructSuite applies SDPWS Table 4.3A Footnote 2 when enabled: Va uses the 15/32 capacity instead of the base row, when stud spacing ≤ 16 in. or panels long dimension across studs. Uses §4.1.4.2 for wind. This often avoids upgrading to thicker panels.

Steps

1. Step 1: Geometry & Configuration

   Design consideration: 8×8 ft gives h/b=1, no aspect ratio reduction. Square walls maximize capacity per foot. Unit shear = 3000/(8×8) = 47 plf—moderate for residential.

   In StructSuite: Open Step 1: Geometry & Configuration. In Height, h (ft) enter 8. In Length, b (ft) enter 8.

2. Step 3: Load Definition

   Design consideration: 3,000 lb wind typical for 8×8 wall in single-story residential. Value from diaphragm distribution. Wind Va = Vn/2.0; without Footnote 2, 3/8 at 4 in. may be marginal; Footnote 2 upgrade often makes it work.

   In StructSuite: Open Step 3: Load Definition. Under Lateral force at top of shear wall line, in W — Wind (lb) enter 3000.

3. Step 2: Sheathing & Fasteners

   Design consideration: Rows with superscript 2 in Table 4.3A can use 15/32 capacity when Footnote 2 conditions met. 3/8 with 8d at 4 in. gives base Vn; Footnote 2 upgrades effective capacity. 4 in. edge spacing common for higher demand walls.

   In StructSuite: Open Step 2: Sheathing & Fasteners. In Table 4.3A, select a row with superscript 2 (e.g., Wood Structural Panels - Sheathing, 3/8 in., 8d common). Select 4 in. edge spacing.

4. Step 2: Sheathing & Fasteners

   Design consideration: Footnote 2 recognizes that 3/8 in. panels with adequate fastening (studs ≤16 in. o.c. or long dim across) perform like 15/32—nail withdrawal, not panel thickness, often governs. Saves cost: avoid upgrading to 7/16 or 15/32 when 3/8 meets structural need. Common in production residential; confirm stud spacing on plans before applying.

   In StructSuite: In Step 2: Sheathing & Fasteners, under SDPWS footnote adjustments, check Footnote 2 – Studs ≤16" o.c. or panels long dimension across studs (15/32 in.). Compare Va before and after—capacity increases to 15/32 values.

5. Step 5: Design Verification

   Design consideration: With Footnote 2, Va jumps to 15/32 values—often 30–50% higher than 3/8 base. Confirms adequacy without panel upgrade. Boundary T and C for hold-down; 3,000 lb on 8×8 with 50 plf D gives moderate uplift.

   In StructSuite: Open Step 5: Design Verification. Confirm unit shear demand ≤ Va.

Live design (pre-filled)

The form below is the real StructSuite module with example data loaded. Display only—values cannot be changed.