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Effects of torsion factors on simple non‐linear systems using fully‐bidirectional analyses
Author(s) -
DeLaColina J.
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(199907)28:7<691::aid-eqe834>3.0.co;2-u
Subject(s) - torsion (gastropod) , eccentricity (behavior) , stiffness , structural engineering , perpendicular , amplification factor , equivalence (formal languages) , geology , mathematics , engineering , geometry , bandwidth (computing) , medicine , amplifier , telecommunications , surgery , discrete mathematics , political science , law
Abstract An ensemble of earthquake records is used to carry out non‐linear analyses of simple torsionally unbalanced systems considering both resisting elements and earthquake components along two perpendicular directions. These fully bidirectional analyses are focused to study the effect of the following factors: (i) seismic‐force reduction factor; (ii) factors α and δ used to compute the design eccentricity; (iii) initial lateral period; and (iv) initial stiffness eccentricity. Results indicate that the amplification factor α can be specified as a function of the force reduction factor, the lateral uncoupled period, and the stiffness eccentricity. It is concluded that the coefficient δ depends on the lateral period, the stiffness eccentricity, and the geometrical eccentricity. It was observed that negative shears caused by torsion should be neglected in the design of the stiff element, particularly in the case of systems with large stiffness eccentricity. Results suggest that additional studies should be performed to verify the assumed (partial) equivalence between unidirectional (resisting elements and earthquake components along one direction only) and fully bidirectional analyses to study building torsion problems. Copyright © 1999 John Wiley & Sons, Ltd.