SEISMIC RESPONSE OF TUNED SINGLE DEGREE-OF-FREEDOM SECONDARY SYSTEMS

Modal synthesis procedure for evaluating spectral acceleration in the single degree of freedom (SDOF) secondary system oscillator is studied . Problems encountered in the evaluation of response for secondary osc illators that are tuned or nearly tuned with the primary system modes are discussed and solutions to these problems are presented. A new hyb rid approach is proposed that gives accurate spectral acceleration in tuned secondary systems for both cases of zero and non zero mass ratio in structures that are nonclassically damped. Formulations are develo ped to evaluate the interaction-free (zero mass ratio) instructure spe ctral accelerations for perfectly tuned secondary oscillators in a cou pled primary-secondary system when the two uncoupled systems have same damping characteristics (classical damping case). (C) 1997 Elsevier S cience S.A.