Probe into several important concepts in Chinese current seismic response spectra

Concepts of absolute acceleration response spectra, quasi-acceleration response spectra and pseudo acceleration response spectra are often equated with each other or misused. The values of corresponding spectra can be obtained by using the quasi-spectra relationship, but the spectra characteristics can’t be transformed especially for long period and large damping ratio. The relative displacement spectra does’t conform to the law of structural dynamics and statistical characteristics of strong earthquake response spectra. On this basis, several basic concepts of seismic response spectra, including absolute acceleration response spectra, pseudo acceleration response spectra and the quasi-response spectra, are discussed and compared. The difference and relationship between the spectra are clarified. It is pointed out that the response spectrum in ‘Code for seismic design of building’ is calibrated by the absolute acceleration response spectrum. The quasi spectra relationship is just a mean of numerical conversion and can’t transform the spectra characteristic. The difference between absolute acceleration response spectra and pseudo acceleration response spectra in seismic design is analyzed. The problems are pointed out in current seismic design of building structures by standard response spectra, especially for seismic energy dissipation of the super-high buildings: the seismic design forces are significantly greater than the elastic resisting forces when structures have a long period and large damping ratio, and the result is conservative. Spectra characteristics derived from quasi-spectra relationship are often confusing and lack reliable analysis for designing. Finally, suggestion to construct response spectra by category is given.