The improvement of the seismic-resistant design for existing and new structures using damage concept

In this paper a consistent method including low cycle damage criteria in the seismic design is proposed. It is based on the estimation of the number of inelastic cycles and on the statistical characterization of the distribution of their amplitudes. A damage factor is obtained that is also a function of the earthquake damage potential by means of the I_D index and of the influence of the structural damage by means of the low cycle fatigue parameter b. In this way damage strength and displacement spectra are obtained in order to improve the seismic resistant design including damage effect. The estimation of the number of plastic cycles also provides the assessment of the demand of hysteretic energy.