Overturning Stability of Foundation

A photo taken in Mandalay, Myanmar, after the M8.2 earthquake event. This emphasizes the importance of checking foundation stability. It must be ensured that the foundation has sufficient safety against overturning, i.e.

Loading Condition	Minimum Factor of Safety (FoS)
Gravity + Wind	≥ 1.5
Seismic (ASCE 7 Ultimate Combination)	≥ 1.0
PBD with controlled uplift	≥ 1.0, or allow uplift with checks on re-centering
Uplift anchorage in pile	Use ϕ·Tn ≥ Tu, φ = 0.9 (ACI 318 tension steel)

Case	Apply Ω0?	Why
Anchor bolt design (tension)	✅ Yes	Prevent brittle pullout failure
Pile uplift design	✅ Yes	Prevent pile tension rupture
Foundation overturning check if above is ductile	❌ No	Allow rocking/uplift — check at design seismic level (ρE)
Foundation overturning check to ensure no sliding/failure	✅ Sometimes	If foundation is designed to remain elastic
Column baseplate shear key check	✅ Yes	Brittle failure — must use Ω0 amplified forces