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Seismic torsional provisions for dynamic eccentricity
Author(s) -
Tso W. K.,
Dempsey K. M.
Publication year - 1980
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.4290080307
Subject(s) - eccentricity (behavior) , displacement (psychology) , bilinear interpolation , structural engineering , moment (physics) , enhanced data rates for gsm evolution , physics , mathematics , engineering , classical mechanics , telecommunications , psychology , statistics , political science , law , psychotherapist
A study is made of the dynamic torsional response of a single mass partially symmetric system to ground excitation. Using the response spectrum technique, the torsional response and dynamic eccentricity are determined as functions of the eccentricity of the system and its uncoupled frequency ratio. It is shown that the dynamic eccentricity can best be expressed as a bilinear function of eccentricity. For the critical condition which occurs when the uncoupled frequency ratio is unity, a comparison is made with the torsional provisions of five seismic codes (Canada, Mexico, New Zealand, ATC3 and Germany). It is shown that the first four codes underestimate the torsional moment, and also the edge displacement of the system, significantly when the eccentricity is small and the uncouped torsional and lateral frequencies are close.