The effect of joint flexibility on the free elastic vibration characteristics of steel plane frames

The present work offers a simplified approach for establishing the effect of joint flexibility on the free vibration characteristics of steel plane frames. Based on the beam-to-column model of Eurocode 3, the presented analysis shows that within the elastic range and under certain combinations of the parameters involved, a transition to a higher vibration mode may occur, a finding of great importance for structural design purposes. Numerical results of an L-shaped steel frame, considered either rigid or semi-rigid, in tabular and graphical form, reveal the pronounced effect of the joint's stiffness and its specific role especially on higher vibration modes, implying that the actual flexible joint behavior should be accounted for, even in the elastic range. (C) 2003 Elsevier Science Ltd. All rights reserved.