Optimum Participation of Beams and Columns in Lateral Resistance of Steel Moment Frames

Abstract

For the purpose of understanding the behavior of steel moment frames, optimum participation of beams and columns in lateral resistance of moment frames subjected to earthquake force is represented in terms of lateral displacement of stories depends on height of the building. This optimum participation will be introduced in terms of the ratio of story drift over maximum allowable drift.  As the height of a building rises, the structural designer can take beams into participation in lateral resistance more by choosing the bigger ratio for story drift. Five steel moment frames 2, 3, 4, 5 and 10 steel frames by different bays are subjected to earthquake load which are modeled in ETABS2000 to work on. Since the lateral displacement is usually the main concern in the design of multistory buildings, the smaller lateral displacement is the favorable in this paper. Relative tables are presented and general advices in the design of steel moment frames are given which can be applied in the design of proposed structural system with regard to the ratio of flexural stiffness of beams over the flexural stiffness of columns in each story.

Keywords: Flexural stiffness, lateral displacement, optimum participation, optimum ratio and steel moment frame.