NBC 2020 Stability Factor

The stability factor (θ_x) at level x

θ_{x} = \frac{\sum_{i = x}^{n} W_{i}}{R_{o} \sum_{i = x}^{n} F_{i}} \frac{∆_{mx}}{h_{s}}

#formula@001475#	Portion of the factored dead plus live load at level x
#formula@001476#	Sum of the design lateral seismic forces acting at or above level x
R_o	Overstrength-related modification factor
Δ_mx	Max inelastic interstory deflection
h_s	Interstory height

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