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Capacity spectrum method based on inelastic demand spectra
Author(s) -
Fajfar Peter
Publication year - 1999
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/(sici)1096-9845(199909)28:9<979::aid-eqe850>3.0.co;2-1
Subject(s) - spectral line , displacement (psychology) , representation (politics) , spectrum (functional analysis) , basis (linear algebra) , structural engineering , response spectrum , computer science , algorithm , mathematics , engineering , geometry , physics , quantum mechanics , psychology , politics , political science , law , psychotherapist
By means of a graphical procedure, the capacity spectrum method compares the capacity of a structure with the demands of earthquake ground motion on it. In the present version of the method, highly damped elastic spectra have been used to determine seismic demand. A more straightforward approach for the determination of seismic demand is based on the use of the inelastic strength and displacement spectra which can be obtained directly by time‐history analyses of inelastic SDOF systems, or indirectly from elastic spectra. The advantages of the two approaches (i.e. the visual representation of the capacity spectrum method and the superior physical basis of inelastic demand spectra) can be combined. In this paper, the idea of using inelastic demand spectra within the capacity spectrum method has been elaborated and is presented in an easy to use format. The approach represents the so‐called N2 method formulated in the format of the capacity spectrum method. By reversing the procedure, a direct displacement‐based design can be performed. The application of the modified capacity spectrum method is illustrated by means of two examples. Copyright © 1999 John Wiley & Sons, Ltd.