scholarly journals EMPIRICAL MODEL OF AMPLIFICATION FACTORS OF LONG-PERIOD RESPONSE SPECTRA AND ITS PHYSICAL INTERPRETATION

2011 ◽  
Vol 76 (669) ◽  
pp. 1905-1914 ◽  
Author(s):  
Toshimi SATOH ◽  
Izuru OKAWA ◽  
Takao NISHIKAWA ◽  
Toshiaki SATO
2016 ◽  
Vol 32 (4) ◽  
pp. 2109-2126 ◽  
Author(s):  
W. D. Liam Finn ◽  
Francisco Ruz

The amplification effects of shallow soft-surface layers with respect to an underlying hard-soil layer or rock are studied using data recorded from the 2011 Tohoku earthquake. Twenty-four sites have been studied with depths to rock ranging from 4–30 m. At each site, two records were available: one in rock at the bottom of the borehole at depths of 100–500 m and one on the surface of the soft-soil layer. Analyses of the soil-rock columns were conducted using the program SHAKE. Good agreement was found between calculated and recorded surface spectra, which demonstrated the reliability of SHAKE analyses for the sites under study. Therefore, SHAKE analyses were used to determine the outcrop motions at the top of rock. Amplification factors were determined by comparing characteristics of the surface and outcrop motions such as Fourier and response spectra. Computed amplification factors were correlated with V S30, V soil, and soft layer period, T = 4 H/ V soil. The results show clearly that the most reliable correlations for estimating the amplification of soft shallow surface layers less than 30 m are those based on V S30 and soft layer period, T.


2020 ◽  
Author(s):  
Maria D'Amico ◽  
Erika Schiappapietra ◽  
Giovanni Lanzano ◽  
Sara Sgobba ◽  
Francesca Pacor

<p>We present a processing scheme (eBASCO, extended BASeline COrrection) to remove the baseline of strong-motion records by means of a piece-wise linear de-trending of the velocity time history. Differently from standard processing schemes, eBASCO does not apply any filtering to remove the low-frequency content of the signal. This approach preserves both the long-period near-source ground-motion, featured by one-side pulse in the velocity trace, and the offset at the end of the displacement trace (fling-step). Hence, the software is suitable for the identification of fling-containing strong-motion waveforms. Here, we apply eBASCO to reconstruct the ground displacement of more than 400 three-component near-source waveforms recorded worldwide (NESS1, http://ness.mi.ingv.it/; Pacor et al., 2019) with the aim of: 1) extensively testing the eBasco capability to capture the long-period content of near-source records; 2) calibrating attenuation models for peak ground displacement (PGD), 5% damped displacement response spectra (DS), permanent displacement amplitude (PD) and period (Tp). The results could provide a more accurate estimate of ground motions, to be adopted for different engineering purposes such as performance-based seismic design of structures.</p><p>Pacor F., Felicetta C., Lanzano G., Sgobba S., Puglia R., D’Amico M., Russo E., Baltzopoulos G., Iervolino I. (2018). NESS v1.0: A worldwide collection of strong-motion data to investigate near source effects. Seismological Research Letters. https://doi.org/10.1785/0220180149</p>


2010 ◽  
Vol 26 (4) ◽  
pp. 1139-1139
Author(s):  
Steven M. Day ◽  
Robert Graves ◽  
Jacobo Bielak ◽  
Douglas Dreger ◽  
Shawn Larsen ◽  
...  

2019 ◽  
Vol 35 (4) ◽  
pp. 1663-1688 ◽  
Author(s):  
Esengul Cavdar ◽  
Gokhan Ozdemir ◽  
Beyhan Bayhan

In this study, an ensemble of ground motions is selected and scaled in order to perform code-compliant bidirectional Nonlinear Response History Analysis for the design purpose of both short- and long-period structures. The followed scaling method provides both the requirements of the Turkish Earthquake Code regarding the scaling of ground motions and compatibility of response spectra of selected ground motion pairs with the target spectrum. The effects of four parameters, involved in the followed scaling method, on both the amplitude of scale factors and seismic response of structures are investigated. These parameters are the number of ground motion records, period range, number of periods used in the related period range, and distribution of weight factors at the selected periods. In the analyses, ground motion excitations were applied to both fixed-base and seismically isolated structure models representative of short- and long-period structures, respectively. Results revealed that both the amplitudes of scale factors and seismic response of short-period structures are more prone to variation of investigated parameters compared to those of long-period structures.


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