A free-standing compound wall's governing lateral load is the worse of two actually different alternatives — wind pressure or retained earth. Never their sum, and the engine has to decide which one actually controls before any design can begin.
Every check above runs automatically inside the Structyze RCC Compound Wall module — this particular module is part of the full desktop catalogue rather than the free browser trial, since the trial only carries a curated flagship set. You can still try the free trial modules right now to see the same calculation style in action on RCC Beam, Column, Slab and a handful of others.
The Example We'll Use
- Height above ground 6.5 ft (2 m)
- Stem 6 in; footing 4.6 ft wide × 10 in
- Wind pressure 25 psf; retained earth height 0
- Concrete f′c = 3000 psi, steel fy = 60 ksi; cover 1.5 in
- Allowable bearing 2.0 ksf, friction coefficient 0.5
Working Through It
Comparing the two overturning moments closely: wind gives Mo ≈ 664 lb-ft per foot, while zero retained-earth height gives Mo = 0. Wind governs outright — and critically, wind carries a load factor of just 1.0 (combination 1.2D+1.0W), materially gentler than the 1.6 factor ACI 318 would apply to a retained-earth case.
Stability checks all clear with wide margin: overturning FS = 3.7, sliding FS = 3.3, both well above the 1.5 minimum. The resultant eccentricity check, though, runs much tighter — e = 0.63 ft against a middle-third limit of B/6 = 0.77 ft, utilisation 0.82.
Stem flexure, using the 1.0 wind load factor, needs only minimum steel (#3 at 6 in) — the stem itself is barely stressed even though the wall as a whole is governed by wind.
What Governs, and Why
The middle-third eccentricity check governs at utilisation 0.82 — tighter than either named stability factor of safety (overturning 0.41, sliding 0.46 as fractions of their limits). A short boundary wall on a narrow footing is characteristically governed by this geometric check, not by strength; if the ground is stepped on one side, the engine switches to the earth case with its steeper 1.6 load factor instead.
Where Structyze Takes Over
Every check above runs automatically inside the Structyze RCC Compound Wall module — this particular module is part of the full desktop catalogue rather than the free browser trial, since the trial only carries a curated flagship set. You can still try the free trial modules right now to see the same calculation style in action on RCC Beam, Column, Slab and a handful of others.
For RCC Compound Wall and the rest of the full catalogue — 80+ components across RCC, Steel, Composite, Timber, Masonry and more, across 20+ design codes — buy the full Structyze desktop app or see everything it does on the Software page.
Quick FAQ
Why would wind ever govern over retained earth for a boundary wall?
Because the two loads are genuinely different physical mechanisms with different load factors and different moment arms — a wall with no grade difference across it (zero retained-earth height) has no earth-pressure case to compete with wind at all, so wind governs by default whenever there's no step in grade.
Why is wind pressure a direct input rather than derived from wind speed?
This module takes design wind pressure as a project input rather than deriving it from a site basic wind speed through the full ASCE 7 procedure — keeping the module focused on the wall's stability and structural design once the pressure is known, with the wind-speed-to-pressure conversion left to the engineer's own ASCE 7 calculation.
Final Thoughts
A compound wall's either-or load logic (wind versus earth, never both) is a clean example of how getting the governing case right matters as much as the arithmetic that follows it.