Wood Shear Wall Overturning Moment Guide
What This Calculator Does
Wood shear walls resist wind and seismic loads. They also create overturning at the base. That moment can lift one end of the wall. It can also increase compression at the opposite end. This calculator helps estimate that demand in a clear way. It uses wall height, wall length, lateral forces, gravity loads, and hold down capacity.
Why Overturning Matters
A wall can have enough shear capacity and still fail at its ends. The uplift end may need a hold down. The compression end may need blocking, studs, posts, or bearing support. Overturning checks help connect the wall to the floor, foundation, and roof system. They also help compare different wall lengths. A longer wall usually lowers uplift demand. A taller wall usually raises overturning demand.
Inputs Used in the Check
The main inputs are lateral force and load height. You may enter one roof force or several story forces. Each force is multiplied by its height above the base. The sum gives the raw overturning moment. A load factor can increase the demand. A reduction field can model approved reductions, when your design method allows them. Gravity loads are entered with a lever arm from the compression toe. Their moment reduces uplift demand.
Reading the Results
The calculator reports base shear, overturning moment, resisting moment, required hold down tension, available hold down strength, and demand ratio. A ratio at or below one means the entered hold down capacity is enough for the calculated demand. It does not prove that the full wall design is complete. Sheathing, nailing, chords, anchors, collectors, and load path still need review. The tool also shows unit shear. That value helps compare wall demand with sheathing schedules.
Good Practice Notes
Use consistent units. Do not mix feet with meters or pounds with kilonewtons. Enter service or factored loads based on one design approach. Check local code rules before applying reductions. Use conservative lever arms when load paths are uncertain. Review end post capacity with the uplift value shown. Also review anchor spacing and sill plate bearing. Treat this result as a planning aid. Final wall design should be checked by a qualified professional. Keep assumptions with project notes for later review.