Study on Relative Displacement Response Spectrum of Long-period Structures
CAO Jia-liang1; SHI Wei-xing1; LIU Wen-guang2; JIANG Xiang-min3
1. Research Institute of Structural Engineering and Disaster Reduction , Tongji University , Shanghai, 200092 , China; 2. Civil Engineering Department of Shanghai University, Shanghai, 200072 , China; 3.CNGC Wuzhou Engineering Design and Research Institute, Beijing, 100053, China
Abstract：Relative displacement response spectrum is not only essential in seismic design of long-period structures but also in displacement-based seismic design and in structural control design. However, spectrum specified by seismic codes is almost some normalized absolute acceleration spectrum. Problems existing in long-period range of relative displacement spectrum in codes were pointed out. By selecting 80 high-pass filtered digital horizontal strong motion records (PGA (Peak Ground Acceleration)≥0.10 g) with low cut off frequency (0.025 Hz ~0.125 Hz), relative displacement spectrum was constructed with period range (0~10.0 s) and damping ratio range (0.10~0.40). Furthermore, spectral influence factors and control parameters were calculated and illustrated. Taken account into influence on relative displacement spectrum of hypocenter parameters, ground motion amplitude, site conditions, spectral control parameters and damping ratio adjustment factors, elastic design displacement spectrum and relevant practical calculation formula for long-period structures were proposed. Moreover, value of PGD (peak ground displacement) was given based on statistical analysis. The results reveal that predominant period is one of significant parameters controlling value and shape of the relative displacement spectrum, and the relative displacement spectrum established in this paper is capable of yielding relatively good satisfaction with real displacement spectrum.
2011, Vol. 30 
