Moment-Rotation Characteristics of Column Anchorages

In this paper are presented methods of determining the moment-rotation characteristics for common types of column anchorages found in light industrial buildings. These characteristics are useful in methods of analysis or design, particularly for cases in which resistance to rotation may be critical to the survival of the structure under heavy lateral loads such as earthquakes or blast loads. Upper and lower bounds for maximum resisting moment and maximum rotation, respectively, are developed. Shear is found to have little effect on the ultimate resisting moment but has somewhat more effect on the maximum rotation. Formulation of the complete moment-rotation curve is developed in five stages. Appendixes illustrate the use of the formulas. The variables involved are examined, and the effect of each on the ultimate moment and rotation is shown graphically. The procedure developed may provide at least a first approximation until experimental data become available which will allow corroboration or correction of the assumptions that have been made.