Shear Wall Aspect Ratio Check: Tall Wall Design per SDPWS 4.3.3

Summary: Design a 10 ft × 4 ft wood shear wall where h/b exceeds 2:1. SDPWS 4.3.3.2 aspect ratio factor and Table 4.3A apply. A narrow 10 ft tall × 4 ft wide…

Overview

Building / scenario

• Occupancy / use: Residential
• Geometry / size: 10 ft × 4 ft (h/b = 2.5)
• Site / exposure: ASCE 7-22

Problem statement

A narrow 10 ft tall × 4 ft wide shear wall in a residential building carries 1,800 lb wind load at the top. Aspect ratio h/b = 2.5 exceeds the 2:1 limit for unblocked wood structural panels (SDPWS Table 4.3.3). Apply the 4.3.3.2 adjustment factor. Dead load is 40 plf. Select sheathing, verify capacity, and size hold-down.

Workflow in StructSuite

StructSuite's free shear wall design calculator applies SDPWS §4.3.3 (aspect ratio limits), §4.3.3.2 (adjustment factor 1.25 - 0.125(h/b) when h/b > 2), Table 4.3A (Vn), and §4.1.4.2 (Va = Vn/2.0 for wind). Design verification shows 4.3.5.5.1 Exception 1 and 4.3.3.2 checks. Step 4: select hold-down model.

Design considerations (excerpt)

h/b = 2.5 exceeds SDPWS Table 4.3.3 limit of 2:1 for unblocked panels. Tall narrow walls are flexible—more drift, less effective as cantilever. Factor 1.25 − 0.125(h/b) = 0.9375 reduces capacity. Adding width (b) or using blocked construction avoids reduction. Common where openings (window, door) limit wall width.

1,800 lb for 10×4 ft wall = 450 plf unit shear. Moderate wind zones (Risk Cat II) often govern over seismic for single-story. In SDC D+, seismic may control—check both when both apply.

40 plf is light—typical for narrow wall with minimal tributary. Lower D increases hold-down demand: T ∝ V×h − 0.6D×b²/2. Narrow wall + light D = large T; may need HDUE-size hold-down instead of…

Related terms

• StructSuite
• structural engineering
• design example
• shear wall
• SDPWS
• tall wall aspect ratio

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