Input energy spectra for self-centering SDOF systems

2019 ◽  
Vol 121 ◽  
pp. 293-305 ◽  
Author(s):  
Ying Zhou ◽  
Ge Song ◽  
Shimin Huang ◽  
Hao Wu
Keyword(s):  
Energy Spectra ◽  
Input Energy

The Inelastic Input Energy Spectra for Main Shock–Aftershock Sequences

2016 ◽  
Vol 32 (4) ◽  
pp. 2149-2166 ◽  
Author(s):  
Changhai Zhai ◽  
Duofa Ji ◽  
Weiping Wen ◽  
Weidong Lei ◽  
Lili Xie ◽  
...  
Keyword(s):  
Seismic Design ◽  
Main Shock ◽  
Degree Of Freedom ◽  
Energy Spectra ◽  
Site Conditions ◽  
Input Energy ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Earthquake Records ◽  
Aftershock Sequences

This study investigates the input energy spectra for inelastic single-degree-of-freedom (SDOF) systems under main shock–aftershock sequences. The input energy spectra quantitatively reveal the effects of aftershocks on input energy, which verifies the necessity of incorporating aftershocks in energy-based seismic design. The investigation selects the sequences including one aftershock or two aftershocks respectively, according to the proposed criteria for selecting earthquake records. Then, the input energy for sequences is normalized by mass, m, and expressed in terms of the equivalent velocity, V E, seq. Next, the variation of V E, seq is studied in consideration of the hysteretic models, ductility values, periods of vibration, site conditions, relative intensities of aftershocks and number of aftershocks. The results indicate that the effects of aftershocks on input energy are significant in almost the whole period region. Finally, a simplified expression of input energy is proposed for incorporating aftershocks in energy-based seismic design.

Damping effect on seismic input energy and its verification by shake table tests

2021 ◽  
pp. 136943322110105
Author(s):  
Ahmet Gullu ◽  
Ercan Yuksel ◽  
Cem Yalcin ◽  
Oral Buyukozturk
Keyword(s):  
Damping Ratio ◽  
Shear Velocity ◽  
Energy Spectra ◽  
Input Energy ◽  
Shake Table Tests ◽  
Seismic Input ◽  
Damping Effect ◽  
Fundamental Frequencies ◽  
Modification Factor ◽  
Dominant Period

Seismic input energy per unit mass ( EI/m) imparted into a structure is a function of earthquake (duration, frequency content, amplitude etc.), soil (shear velocity, dominant period etc.) and the structural (vibrational periods etc.) characteristics. Generally, the damping properties of the structure is assumed negligible for seismic input energy. Most of the existing spectral equations derived for SDOF systems generally use a constant damping ratio of 5%. In this study, the damping effect on EI/m is investigated experimentally and numerically on SDOF systems with distinct damping ratios. Experimental investigation and numerical computations proved that seismic input energy is very sensitive to variation of damping within the vicinity of fundamental frequencies. Specifically, up to 50% increment was observed in the plateau region of the input energy spectrum, where maximum EI/m values occur, by variation of damping from 2% to 10%. Hence, a novel damping modification factor ( DMF), which could be utilized for existing energy spectra, is proposed in this paper. Validation studies of the proposed DMF are achieved through the various energy spectra found in the literature.

A Study on Elastic Input Energy Spectra Based on the Compound Intensity Indicator

2012 ◽  
Vol 446-449 ◽  
pp. 140-145
Author(s):  
Li He ◽  
Xian Guo Ye
Keyword(s):  
Ground Motion ◽  
Damping Ratio ◽  
Energy Spectra ◽  
Site Classification ◽  
Input Energy ◽  
Damage Potential ◽  
Normalization Methods ◽  
Seismic Records ◽  
Energy Based Design

Determination of a SDOFS elastic input energy is the primary problem to solve for energy-based design approach. The effect of ground motion and damping ratio were analyzed on the input energy spectra. is selected as the compound ground motion intensity indicator to represent the damage potential of strong ground motion. Through inputting of 188 seismic records according to the site classification of Chinese seismic code, three-segment elastic energy spectra are proposed based on normalization methods. The calculation formula of the peak and the value of long-period section of the input energy spectra are presented for four categories of site conditions by statistical analysis. Moreover, calculation procedure of the total energy input is given in the paper.

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