APPLICATION OF CONDITIONAL MEAN SPECTRUM ON SUPER HIGH-RISE BUILDING IN SOFT SOILS

Accurate and reliable prediction of structural performance under earthquake requires appropriate ground motion selection. The most important steps are to specify the target spectrum and to select the matching and scaling methods correspondingly. The inherit problem of the commonly utilized Uniform Hazard Spectrum (UHS) is too conservative, while Conditional Mean Spectrum (CMS) based on synthesis and de-aggregation of seismic hazard overcomes this drawback, which has been widely concerned round the world. However, some issues on the application of CMS on soil zones and super high-rise structures remain unaddressed. This paper focuses on the typically super high-rise building in Shanghai site, Shanghai Tower. Based on the Probabilistic Seismic Hazard Analysis, the spectral acceleration at the first fundamental period with 10% of exceedance in 50 years was determined. Then, de-aggregation of probability seismic hazard was carried out to determine the mostly contributed ground motion and spectral parameters at the first fundamental period of SHT in accordance with the attenuation of Shanghai site. CMS can be created and compared with Shanghai Standard Spectrum when utilized as the target spectrum to select ground motions by matching target mean and variance, and inter-storey drift ratios are compared. Results show that ground motion suite targeted on CMS has larger dispersion, and Shanghai Standard Spectrum is conservative to long-period structures.