What it checks
The module designs segmented or perforated wood shear walls. It evaluates the structural capacity of the wall assembly, including the sheathing and fasteners, to resist lateral loads. The design method utilizes Allowable Strength Design (ASD) for hold-down and sill bolt checks, as indicated by the use of ASD capacities and factors.
The sequence of checks begins with determining the nominal unit shear capacity based on sheathing type, nail size, and spacing. It then calculates the total drift at the top of the wall and compares the drift ratio against standard limits. Finally, the module assesses the demand on sill bolts and hold-down devices, comparing these demands against their respective tabulated ASD capacities.
Inputs
- Sheathing and Fasteners - Sheathing type, nail type, and nail spacing (in).
- Stiffness Properties - Apparent shear stiffness Ga (lbs/in) and chord modulus of elasticity (psi).
- Chord Geometry - Chord cross-sectional area (in²); set to 0 to skip the bending term.
- Deformation Parameters - Anchor bolt elongation and plate bearing deformation (in), and hold-down device deformation at design load (in).
- Sill Bolt Details - Anchor bolt nominal diameter (in) and anchor bolt spacing (in); set diameter to 0 to skip the sill bolt check.
- Hold-Down Capacity - Tabulated ASD hold-down capacity (kips) from manufacturer ICC-ES ESR; set to 0 to skip the hold-down check.
What it reports
- Nominal Unit Shear - The nominal unit shear capacity (plf) for the specified sheathing, nail, and spacing combination.
- Total Drift - The total calculated drift at the top of the wall (in); reports 0 if inputs are insufficient.
- Drift Ratio - The dimensionless drift ratio δ/H, intended for comparison to ASCE 7 limits such as 0.020 for seismic or 1/240 for wind.
- Sill Bolt Demand - The shear demand per sill bolt (kips).
- Sill Bolt Capacity - The ASD capacity per sill bolt (kips) after applying the CD factor.
- Hold-Down Demand - The net uplift demand on the hold-down (kips); a negative value indicates gravity restrains the wall and no hold-down is needed.
- Hold-Down Capacity - The tabulated ASD hold-down capacity (kips); reports 0 if the check is skipped.
Code references
The engine cites SDPWS 2021 §4.3.3, Table 4.3A, and Table 4.3B, as well as NDS 2018. It also references ASCE 7 limits for drift comparison and ICC-ES ESR for hold-down capacities.
Limits
The module skips the bending term if the chord cross-sectional area is set to 0. It skips the sill bolt check if the anchor bolt diameter is set to 0. It skips the hold-down check if the hold-down capacity is set to 0. The drift calculation uses a table lookup if the apparent shear stiffness Ga is 0. Results are engineering aids; the engineer of record is responsible for the design.