Proposal of Design Lateral Load for Column Joint of Steel Moment Frame

According to the current design recommendations in Japan, column-to-column connections of steel building structures, also known as column splices, must remain elastic under severe earthquakes, even when the ultimate state of the structure is reached. Therefore, the design bending strength for column-to-column connection is required to be larger than both the bending moment at the column-to-column connection at the ultimate state of the structure and one-half of the yield strength of the original column. However, in the authors’ previous study, which investigated the required bending strength for column-to-column connections by conducting numerical analyses of steel moment frames, the maximum bending moment of column-to-column connections may not occur at the ultimate state of the frame. Hence, the design recommendations for column-to-column connections in Japan cannot properly evaluate the required strength for column-to-column connections in some cases. Based on the above, this study further analyzes the results of time-history analyses and static pushover analyses on steel moment frames to clarify the shortcomings of the current design method for column-to-column connections. Furthermore, a method for predicting the maximum bending moment acting on column-to-column connections is proposed to complement the current design recommendations. The major parameters are the number of stories, floor height, input direction, phase and intensity of the ground motion.