Treatment of Eccentrically-loaded Connections in the AISC Manual

As in earlier editions, the recommended loads for eccentrically loaded connections and the coefficients tabulated in the AISC Manual of Steel Construction, 7th Edition, for their design are more conservative than might be expected in view of recent studies and tests. (See the paper by Carl L. Shermer in this issue of the Engineering Journal.) However, there are a number of factors—including the need for further research into the plastic behavior of large connections subject to considerable eccentricity of loading— which discouraged across-the-board adaptation of these findings during preparation of the 7th Edition of the Manual. Unfortunately, calculation of the plastic strength of eccentrically loaded fastener patterns requiring the determination, by an iterative procedure, of the center of rotation satisfying the three equations of equilibrium would be far too tedious using ordinary slide-rule methods. Therefore, resort to the familiar vector method of analysis, even at the sacrifice of some economy in fabrication cost, would still be justified in evaluating unusual fastener patterns.