Estimating the peak structural response of high-rise structures using spectral value-based intensity measures

With increasing trend towards performance-based design in earthquake engineering, running nonlinear time history analysis is becoming the routing process to quantify the relationship between ground motions intensity measure (IM) and the structural responses. Because a high-rise structure contains many higher modes, a newly proposed spectral value-based IM is presented in this paper to quantify the structural response of high-rise structures. The newly proposed IM uses the modal participation masses to combine higher modes. An actual high-rise structure is taken as an example to demonstrate the efficiency of using the newly proposed IM to quantify the peak structural response of high-rise structures. Five alternative IMs were compared in this study: (a) PGA - peak ground acceleration; (b) S1 - spectra acceleration with only 1 mode; (c) S* - modified S1 with the consideration of period elongation after structure yielded; (d) S12- spectra acceleration with 2 modes; and (e) S123 - spectra acceleration with 3 modes. Linear regression is fitted between the peak structural response and the IM considered. The IM with the highest correlation coefficient to the engineering demand parameter is considered the most efficient IM. The results show that S1 has better correlation to the structural response compared with PGA. S123 has better correlation than S* and S12. It is found that the IM with higher modes can provide better correlation than IM with lower number of structural information. For engineering applications, IM with up to 3 modes (S123) is sufficient to produce an accurate prediction to quantify the structural response of high-rise structures.