ELUCIDATION OF TRANSITION OF NATURAL PERIODS OF BUILDINGS BASED ON ELASTO-PLASTIC RESPONSE SPECTRUM WITH CONSTANT DAMPING FACTOR

Abstract

A theoretical approach of elasto-plastic response with constant damping factor is proposed to evaluate transition of natural periods of buildings. The spectrum of the elasto-plastic response is equivalent to that of visco-elastic response in following respects: both values of dissipative energy during one cycle are exactly same, shapes and amplitudes of both spectra are approximately same, the spectrum of elasto-plastic system shows linear response with fluctuations in amplitudes of input motions. The equivalent period of elasto-plastic system indicates significant relation between response amplitude of the system. This mechanism gives appropriate interpretation on the observed transition of natural periods of buildings.