Techno Press
Techno Press

Earthquakes and Structures
  Volume 13, Number 3, September 2017 , pages 231-239
DOI: https://doi.org/10.12989/eas.2017.13.3.231
 


A simple approach for the fundamental period of MDOF structures
Yan-Gang Zhao, Haizhong Zhang and Takasuke Saito

 
Abstract
    Fundamental period is one of the most critical parameters affecting the seismic design of buildings. In this paper, a very simple approach is presented for estimating the fundamental period of multiple-degree-of-freedom (MDOF) structures. The basic idea behind this approach is to replace the complicated MDOF system with an equivalent single-degree-of-freedom (SDOF) system. To realize this equivalence, a procedure for replacing a two-degree-of-freedom (2-DOF) system with an SDOF system, known as a two-to-single (TTS) procedure, is developed first; then, using the TTS procedure successively, an MDOF system is replaced with an equivalent SDOF system. The proposed approach is expressed in terms of mass, stiffness, and number of stories, without mode shape or any other parameters; thus, it is a very simple method. The accuracy of the proposed method is investigated by estimating the fundamental periods of many MDOF models; it is found that the results obtained by the proposed method agree very well with those obtained by eigenvalue analysis.
 
Key Words
    fundamental-period estimation; seismic design; MDOF structures; TTS procedure; equivalent SDOF system
 
Address
Yan-Gang Zhao, Haizhong Zhang and Takasuke Saito: Department of Architecture, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan
 

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