A Practical Direct Displacement-Based Seismic Design Method for Building Frame Structures

This paper introduces a practical approach for analyzing frame-type structures within the framework of the direct displacement-based design (DDBD) method. In this approach, frame-type structures are idealized as equivalent shear beams to represent their global seismic behavior. On the basis of this assumption, a series of numerical analyses of equivalent shear beams with varying numbers of stories were conducted in SAP2000, from which relationships for the maximum interstories drift ratio, effective mass, and effective height were established. The derived relationships are presented in tabular and graphical form for practical application, enabling the DDBD method to be applied in a rapid and efficient manner. The proposed method departs from the classical DDBD procedure by modeling the frame system as an equivalent shear beam instead of converting it into an SDOF system. At the end of the study, the proposed method was demonstrated step by step using an example. Additionally, various building types in the literature were analyzed using both the proposed approach and the traditional DDBD method to evaluate the effectiveness and suitability of the new approach. The results demonstrate that the proposed method is highly effective for high-rise buildings with six or more stories. Conversely, for low-rise buildings, it yields higher base shear forces, a consequence of their shorter fundamental periods, when compared with the conventional DDBD method.