Shear Wall Hold-Down and Anchor Bolt Selection per SDPWS

Example

An 8 ft × 6 ft wood shear wall in SDC D carries seismic lateral force E = 4,500 lb and dead load 45 plf. Overturning produces tension T at the hold-down. Per SDPWS §4.3.5, §4.3.6, the hold-down must resist net uplift. Select a Simpson Strong-Tie model from the table whose capacity (lb) exceeds max T. The table lists anchor bolt diameter—embedment per ACI 318 or anchor evaluation report. Species DF/SP vs SPF/HF affects capacity; use the correct column.

How StructSuite solves this

StructSuite's free structural design software computes boundary forces T and C per Eq 4.3-7 from geometry, lateral load, and gravity. Open Step 4: Boundary Members & Hold-Downs. Select DF/SP or SPF/HF for framing species. In the Simpson table, click a row (e.g., HDUE3-SDS3 for 3,790 lb DF/SP, 5/8 in. anchor bolt) so capacity ≥ max T. Step 5 Design Verification shows D/C ≤ 1 when adequate.

Steps

1. Step 1: Geometry & Configuration

   Design consideration: h/b = 1.33, within 2:1 limit. Shorter b (6 ft vs 8 ft) increases unit shear and overturning T. For same V, T ∝ 1/b. Narrower walls need larger hold-downs. Blocked construction increases Vn per Table 4.3A.

   In StructSuite: Open Step 1: Geometry & Configuration. In the Shear wall line — segments and spacing area, for Shear Wall 1: in the Height, h (ft) input box enter 8; in the Length, b (ft) input box enter 6.

2. Step 3: Load Definition

   Design consideration: E = 4,500 lb is high for 8×6 ft—typical of SDC D two-story or high weight. Seismic Va = Vn/2.8 (stricter than wind Vn/2.0) reflects cyclic loading. Higher E directly increases both shear demand and overturning T.

   In StructSuite: Open Step 3: Load Definition. Under Lateral force at top of shear wall line, in the E — Earthquake (lb) input box enter 4500.

3. Step 3: Load Definition

   Design consideration: T = (V×h − 0.6D×b²/2) / b. 45 plf is modest; 60–80 plf would reduce T significantly. Doubling D can cut required hold-down capacity 30–50%. Light roof (metal, truss) gives lower D.

   In StructSuite: Open Step 3: Load Definition. Under Gravity loads on walls, click the + Add gravity load button. In the new row, set Type = D in the dropdown; set Distribution = Uniform (lb/ft); in the Value (plf) input box enter 45.

4. Step 2: Sheathing & Fasteners

   Design consideration: Shear capacity must be satisfied first; then overturning drives hold-down. 15/32 at 4 in. edge common for SDC D residential. Tighter (3 in.) adds capacity; 6 in. may be insufficient for 4,500 lb on 6 ft wall.

   In StructSuite: Open Step 2: Sheathing & Fasteners. In the SDPWS 2021 Table 4.3A grid, locate the row for your panel type (e.g., Wood Structural Panels - Sheathing, 15/32 in., 8d common) and click the cell in the column for the desired nail spacing (e.g., 6 in. edge). The nominal unit shear will populate. Open Step 5: Design Verification to confirm wind and seismic capacity checks pass.

5. Step 4: Boundary Members & Hold-Downs

   Design consideration: Simpson table: DF/SP (Douglas Fir, Southern Pine) capacities 5–15% higher than SPF/HF (Spruce-Pine-Fir, Hem-Fir). Match framing species. Embedment: 5/8 in. bolt in 3,000 psi concrete typically needs 10–12 in. min; edge distance ≥ 4.5 in. per ACI 318.

   In StructSuite: Open Step 4: Boundary Members & Hold-Downs. Under Hold-down model, select DF/SP or SPF/HF for species. In the Simpson Strong-Tie table, click the row for a hold-down model (e.g., DTT2Z® for 1825 lb DF/SP, 1/2 in. anchor bolt) whose capacity exceeds the max tension (T) from overturning. The anchor bolt diameter column shows required bolt size. Open Step 5: Design Verification to confirm D/C ≤ 1.

6. Step 5: Design Verification

   Design consideration: D/C < 1 confirms hold-down adequate. Governing combo (often 0.9D+1.0E or 1.0D+0.7E+0.7L) shown. Chord reinforcement ties T into diaphragm; collector carries drag around openings.

   In StructSuite: Open Step 5: Design Verification. Scroll to verify capacity checks pass for each wall. Open Step 6: Summary & Visualization. Use the boundary forces T and C shown for hold-down specification at chord locations. Note: Hold-down sizing UI is under construction.

Live design (pre-filled)

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