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Evaluation of combination rules for peak response calculation in three‐component seismic analysis
Author(s) -
Hernández Julio J.,
López Oscar A.
Publication year - 2003
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/eqe.290
Subject(s) - principal component analysis , seismic analysis , component (thermodynamics) , function (biology) , ground motion , intensity (physics) , mathematics , vertical orientation , horizontal and vertical , geometry , structural engineering , physics , statistics , engineering , optics , evolutionary biology , biology , thermodynamics
The responses, r e , given by several multicomponent combination rules used in seismic codes for determining peak responses to three ground motion components are evaluated for elastic systems and compared with the critical response r cr ; this is defined as the largest response for all possible incident angles of the seismic components and obtained by means of the CQC3‐rule when a principal seismic component is vertical, or the GCQC3‐rule when it departs from the vertical direction. The combination rules examined are the SRSS‐, 30%‐, 40%‐ and IBC‐rules, considering different alternatives for the design horizontal spectrum. Assuming that a principal seismic component is along the vertical direction, the upper and lower bounds of the ratio r e / r cr for each combination rule are determined as a function of the spectral intensity ratio of the horizontal seismic components and of the responses to one seismic component acting alternately along each structural axis. Underestimations and overestimations of the critical response are identified for each combination rule and each design spectrum. When a component departs from the vertical direction, the envelopes of the bounds of the ratio r e / r cr for each combination rule are calculated, considering all possible values of the spectral intensity ratios. It is shown that the inclination of a principal component with respect to the vertical axis can significantly reduce the values of r e / r cr with respect to the case when the component is vertical. Copyright © 2003 John Wiley & Sons, Ltd.