Stability of Columns under Uniform Axial Load with Semirigid Connections

Two simple formulas are presented that evaluate the stability $K‐\mathrm{factor}$ of columns with semirigid connections and with side sway uninhibited or partially inhibited including the effects of a uniformly distributed axial load $q$ in addition to a concentrated end load $P$. The proposed formulas can also be applied to frame stability (unbraced and partially braced) with rigid, semirigid, and simple connections. The proposed formulas are more general and simpler to apply than the well‐known alignment chart. A verification study indicates that their results are within 1.4% of the theoretical values. The effects of a uniformly distributed compressive axial load $q$ on the overall stability of a column become significant when $\mathrm{qh}/P>0.1$ and when $q$ is negative, i.e., $q$ becomes a tensile force. Also, when the end fixities are approaching those of construction type 1 (rigid), the effects of $q$ become more significant than in the case of construction type 3 (semirigid). Examples of steel frames using load and resistance factor design are included that demonstrate their use.