Using Moment and Axial Interaction Equations to Account for Moment and Shear Lag Effects in Tension Members

Abstract

Shear lag effects and moments reduce the strength of structural steel tension members. This shear lag exists when connections to tension members transmit the load through some, but not all, elements of the member (legs of an angle, web and flanges of a Wor tee, etc.) and may result in an eccentrically loaded connection. Recent research on structural tees at the University of Connecticut has shown that the moment produced by eccentric loading depends upon the connection geometry as well as the rotational stiffness of the connection. Once the moments in tension tees and other sections are found, these members may be more correctly and safely designed by accounting for the interaction of bending moment and axial force, instead of the empirical shear lag factors. The rotational stiffness of the connections is shown to be an important design consideration.