CORRELATION OF STRUCTURAL DAMAGE INDEXES WITH STRONG GROUND MOTION PARAMETERS

Comprehensive studies have been carried out to investigate the correlation between structural damage indexes (SDIs) and a number of widely used ground motion intensity (GMI) parameters. To this, Nonlinear time–history analyses of steel and concrete frames are performed under a set of many ground motion records. The frames reflect the features of typical low- to medium-rise structures. The records used in nonlinear time history analyses have intensities to represent a wide range of seismic forces that impose various degrees of elastic as well as inelastic response of the frames. The SDIs were compared with the GMI parameters and correlations between them were investigated through coefficients of correlation and determination. The results revealed that spectrum intensity parameters, having the strongest correlation, are superior to other parameters such as peak ground velocity, peak ground acceleration, and spectral acceleration. It was concluded that both peak ground acceleration/peak ground velocity (A/V) ratio and effective duration significantly influence the damage potential of ground motions, although they are not represented appropriately by the spectral definitions of earthquake excitations in seismic design codes. The ground motion A/V range had a significant effect not only on peak inelastic response but also on hysteretic energy dissipation and stiffness deterioration of stiffness degrading systems. Also, improved damage spectra were proposed to quantify the damage potential of recorded earthquake ground motion. The improved damage spectra are promising for assessment of the performance-based seismic vulnerability of existing structures