ACI STABILITY RESISTANCE FACTOR FOR RC COLUMNS.

Load and resistance factors are used to reduce the probability of overloading, understrength, or both to acceptable levels. The ACI Building Code specifies the use of resistance factors for beam-columns in the following ways: (1) Resistance factors are applied to cross-section strength; and (2) resistance factors are applied to critical buckling strength used in moment magnification due to slenderness effects. Probabilistic examination of ACI resistance factors as used in (1) was reported in an earlier study and is available in the literature. This paper examines the ACI resistance factors as employed in (2) and suggests a value for design office use for computing moment magnification of concrete slender columns.