Papers by Author: Wen Feng Liu

Abstract: Response spectrum curve is the base of seismic design of structures, and mode-superposition response spectrum method is a practical design method of structures. Damping adjustment factors and shape parameters have been adjusted in the new Chinese code (2010) for damping rate is not equal to 0.05. Then, a new mode superposition response spectrum method combined with continuum method is introduced in this paper. Finally, the earthquake shear of a shear-wall structure’s bottom is calculated, and the results of the new method are compared with that of traditional method implemented in PM-SATWE software which is widely used in architectural design institute. The contrast results show that the new method is available and has a good accuracy.

Abstract: The analyses on the statistical response spectra have an important role in determining the earthquake demand. Elastic and inelastic spectra on acceleration of the 205 records on medium-stiff soil site for SDOF systems are presented in statistical analyses. The empirical probability distributions of the spectral values are derived according to the Kolmogorov-Smirnov (KS) goodness-of-fit test. The formula for statistical average spectra of the ground motion ensemble are recommended, which are valuable for current research and code revisal. The results show that the statistical averaged elastic α spectra fits well to the design spectra prescribed in Chinese code when the period is smaller than 2s. The inelastic responses decrease with the increase of ductility demand μ when μ<4. The coefficients of variance of the elastic and inelastic spectra are still large and the dispersion cannot be ignored. The probabilistic distribution of the spectra value on acceleration is validated as the lognormal distributions. The proposed formulas give a good fit to the statistical average values.

Abstract: The seismic performance spectrum is a new kind of the response spectra which is formed according to the designated performance objectives. The performance objectives are changed according to the performance objective level and period of structure, and are different in the acceleration sensitive, velocity sensitive and displacement sensitive range in the seismic performance spectrum. The seismic performance spectrum formulas are derived, which demonstrate the mathematic relationship between the seismic demands of the different performance objective levels and the period of structure. The fitted formulas of the seismic performance spectra for seismic design are obtained due to statistical result of 1085 ground motion records. The new seismic performance spectra are shown in visual three-dimension figures which can represent the seismic demand, performance objective and period of structure in this paper. The philosophy of the seismic performance spectrum is analyzed which reveals the rules for estimating seismic demand of structure at the different performance objective levels. So the multi-objective performance-based seismic design is also proposed using the seismic performance spectrum.