Site response analysis of liquefiable soil employing continuous wavelet transform

2022 ◽  
Vol 12 (1) ◽  
pp. 1-33
Author(s):  
D. Chavan ◽  
T.G. Sitharam ◽  
P. Anbazhagan
Keyword(s):  
Wavelet Transform ◽  
Site Response ◽  
Amplitude Spectrum ◽  
Ground Surface ◽  
Time History ◽  
Response Analysis ◽  
Fourier Amplitude ◽  
Acceleration Time ◽  
Liquefiable Soil ◽  
Fourier Amplitude Spectrum

Propagation of the earthquake motion towards the ground surface alters both the acceleration and frequency content of the motion. Acceleration time record and Fourier amplitude spectrum of the motion reveal changes in the acceleration and frequency content. However, Fourier amplitude spectrum fails to give frequency-time variation. Wavelet transform overcomes this difficulty. In the present study, site response analysis of a liquefiable soil domain has been investigated employing wavelet transform. Three earthquake motions with distinct predominant frequencies are considered. It is revealed that the moment soil undergoes initial liquefaction, it causes a spike in the acceleration time history. Frequency of the spikes is found to be greater than the predominant frequency of the acceleration-time history recorded at the ground surface from the analysis. Interestingly, the spikes belong to the sharp tips of the shear stress-shear strain curve. Immediately after the spike, acceleration deamplification is observed. Post-liquefaction deamplification (filtering) of the frequency components is also observed.

SEISMIC TIME-HISTORY GROUND-MOTIONS FOR A SPECIFIC SITE IN JAKARTA

2015 ◽  
Vol 77 (11) ◽  
Author(s):  
I Wayan Sengara ◽  
Muhammad Addifa Yulman ◽  
Andri Mulia
Keyword(s):  
Seismic Hazard ◽  
Linear Time ◽  
Site Response ◽  
Ground Motions ◽  
Ground Surface ◽  
Time History ◽  
Response Analysis ◽  
Building Collapse ◽  
Surface Development ◽  
Time Histories

Indonesia has developed new seismic building code based on risk-targeted ground-motions adopting 1 % probability of building collapse in 50 years. The new seismic design criterion, which is presented in the code, have combined both seismic hazard and building fragility. For performance-based analysis of high-rise buildings, a complex non-linear time-history analysis is needed. This paper presents results of study on development of the time-history with emphasing on procedure of developing pairs of time-history at ground surface for spesific site in Jakarta with reference to 2012 International Building Codes and ASCE-SEI-7-10. The study involves generation of time-history from reference base-rock through site-response analysis to ground surface. Development of time-history at ground surface with a procedure involving Square Root of the Sum of the Square method (SRSS) in order to reasonably scaled time-histories through spectral matching technique is presented herein. The matched time-histories are developed from various strong-motion records representing different earthquake sources dominant to control the site evaluated from de-aggregation within seismic hazard analysis. This work also adopts baseline corrections in which velocity and displacement components of matched time-histories can be drifted to zero at the end of recorded seismic time.

scholarly journals Feature Extraction Method for Hydraulic Pump Fault Signal Based on Improved Empirical Wavelet Transform

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 824 ◽  
Author(s):  
Zheng ◽  
Wang ◽  
Zhu ◽  
Tang ◽  
Wang
Keyword(s):  
Wavelet Transform ◽  
Power Spectrum ◽  
Amplitude Spectrum ◽  
Hydraulic Pump ◽  
Fourier Amplitude ◽  
Feature Extraction Method ◽  
Empirical Wavelet Transform ◽  
Novel Method ◽  
Feature Information ◽  
Fourier Amplitude Spectrum

There are many interference components in Fourier amplitude spectrum of a contaminated fault signal, and thus the segment obtained based on the spectrum can lead to serious over-decomposition of empirical wavelet transform (EWT). Aiming to resolve the above problems, a novel method named improved empirical wavelet transform (IEWT) is proposed. Because the power spectrum is less sensitive to the contaminated interference and manifests the presence of fault feature information, IEWT replaces the Fourier amplitude spectrum of EWT with power spectrum in segment acquirement, and threshold processing is also introduced to eliminate the bad influence on the acquirement, and thus the best decomposition result of IEWT can be obtained based on feature energy ratio (FER). The loose slipper fault signal of hydraulic pump is tested and verified. The result demonstrates that the proposed method is superior and can extract the fault feature information accurately.

Near-Fault Baseline Correction Method and Appliction in Wenchuan Earthquake

2012 ◽  
Vol 166-169 ◽  
pp. 2517-2521
Author(s):  
Xiao Bo Peng ◽  
Xiao Jun Peng ◽  
Wei Lin Yang
Keyword(s):  
Wenchuan Earthquake ◽  
Response Spectrum ◽  
Amplitude Spectrum ◽  
Time History ◽  
Relative Displacement ◽  
Correction Method ◽  
Baseline Correction ◽  
Fourier Amplitude ◽  
Surface Rupture ◽  
Fourier Amplitude Spectrum

To eliminate the drifting in recordings from Ms8.0 Wenchuan earthquake, a modified two segments baseline correction method is brought up and systematic acceptance standard is presented. The method is applied to recordings from Qingping station and Bajiao station, which are closest stations to surface rupture traces. The effect of baseline correction on acceleration time history, Fourier amplitude spectrum and 5% damped relative displacement response spectrum is analyzed.

scholarly journals Detecting Site Resonant Frequency Using HVSR: Fourier versus Response Spectrum and the First versus the Highest Peak Frequency

2020 ◽  
Vol 110 (2) ◽  
pp. 427-440 ◽  
Author(s):  
Chuanbin Zhu ◽  
Fabrice Cotton ◽  
Marco Pilz
Keyword(s):  
Site Response ◽  
Response Spectrum ◽  
Amplitude Spectrum ◽  
Spectral Ratio ◽  
Peak Frequency ◽  
Fourier Amplitude ◽  
Resonant Frequencies ◽  
Overall Performance ◽  
Fourier Amplitude Spectrum ◽  
Hvsr Technique

ABSTRACT In this investigation, we examine the uncertainties using the horizontal-to-vertical spectral ratio (HVSR) technique on earthquake recordings to detect site resonant frequencies at 207 KiK-net sites. Our results show that the scenario dependence of response (pseudospectral acceleration) spectral ratio could bias the estimates of resonant frequencies for sites having multiple significant peaks with comparable amplitudes. Thus, the Fourier amplitude spectrum (FAS) should be preferred in computing HVSR. For more than 80% of the investigated sites, the first peak (in the frequency domain) on the average HVSR curve over multiple sites coincides with the highest peak. However, for sites with multiple peaks, the highest peak frequency (fp) is less susceptible to the selection criteria of significant peaks and the extent of smoothing to spectrum than the first peak frequency (f0). Meanwhile, in comparison to the surface-to-borehole spectral ratio, f0 tends to underestimate the predominant frequency (at which the largest amplification occurs) more than fp. In addition, in terms of characterizing linear site response, fp shows a better overall performance than f0. Based on these findings, we thus recommend that seismic network operators provide fp on the average HVSRFAS curve as a priority, ideally together with the average HVSRFAS curve in site characterization.

scholarly journals Development of two components acceleration time histories for Semarang, Indonesia, due to Semarang fault earthquake scenarios using 30 meters soil deposit model

2018 ◽  
Vol 159 ◽  
pp. 01043
Author(s):  
Windu Partono
Keyword(s):  
Site Response ◽  
Historical Earthquakes ◽  
Structure Design ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Acceleration Time ◽  
Earthquake Scenarios ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Deposit Model

Development of surface acceleration time histories is important for dynamic analysis of structure design and evaluation. Acceleration time histories usually developed from seismograph records due to specific earthquake event. Following the research conducted by Team for Revision of Seismic Hazard Maps of Indonesia 2010 and 2016, Lasem fault and Semarang fault are two closest and dangerous shallow crustal fault earthquake sources which must be taken into account for seismic mitigation of Semarang. This paper presents the development two components surface acceleration time histories for Semarang caused by Semarang fault earthquake scenarios, with magnitude from 6 Mw to 7 Mw and maximum epicentre distance 15 Km. This research was performed by conducting deterministic hazard analysis, response spectral matching and site response analysis to obtain a pair of modified acceleration time histories. Site response analysis was performed by conducting 30 meters soil deposit model by taking the assumption that the position of bedrock elevation is 30 meters below the surface layer. Modified acceleration time histories were developed from a pair time histories (North-South/NS and East-West/EW direction) collected from worldwide historical earthquakes. Modified time histories were developed due to limited time histories data caused by Semarang fault earthquake source.

Effect of Parameters on Equivalent Number of Cycles Using ‎Nonlinear Seismic Site Response Analysis

2011 ◽  
Vol 255-260 ◽  
pp. 2365-2369
Author(s):  
Emad Gheibi ◽  
Mohammad Hosein Bagheripour
Keyword(s):  
Site Response ◽  
Time History ◽  
Current Approach ◽  
Earthquake Magnitude ◽  
Soil Liquefaction ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Nonlinear Site Response ◽  
Equivalent Number ◽  
Number Of Cycles

The concept of equivalent number of uniform stress cycles, is essential for assessment of soil liquefaction potential. In this regard, various procedures are used to convert random acceleration time history to uniform cycles having amplitude of 0.65 of peak acceleration. Equivalent number of cycles (Neq) defines equivalent energy generated by harmonic loading as that imposed by irregular motion during an earthquake. Neq is assumed to be a function of earthquake magnitude. Over the past years, in accordance with development in methods of soil liquefaction evaluation, various methods have been proposed to determinate equivalent number of cycles. In particular, parameters like site to source distance (r), have been related directly to Neq. In this study, more than 80 earthquake records have been investigated and their Neqs are assessed using energy approach and nonlinear site response analysis. It is shown that equivalent number of cycles is related to earthquake magnitude (M), r and depth of originated signals. Unlike previous methods which result in scatter in output data, current approach has led to more uniform and consistent results for each earthquake.

Performance evaluation of vibration-sensitive equipment foundations under ground-transmitted excitation

2003 ◽  
Vol 40 (3) ◽  
pp. 598-615 ◽  
Author(s):  
M Hesham El Naggar
Keyword(s):  
Ground Surface ◽  
Time History ◽  
Ground Vibration ◽  
Frequency Domain Analysis ◽  
Vibration Monitoring ◽  
Normal Operation ◽  
Response Analysis ◽  
The Third ◽  
Final Design ◽  
Dynamic Investigation

The planning of foundations for equipment that is sensitive to vibrations requires a thorough dynamic investigation of the proposed location of the foundation with regard to the effect of already existing or additional vibration sources. This paper discusses the analyses performed for a number of foundations supporting vibration-sensitive equipment that has been subjected to ground-transmitted excitations. These analyses considered the dynamic response of the foundations resulting from the normal operation of the supported equipment or the ground-transmitted excitations. In one case, the foundation of the Canadian Light Source, a third generation synchrotron that will be capable of generating electromagnetic radiation used in the study of the atomic and subatomic structure of materials, is examined. Another case involves the vibration analysis of a magnetic resonance imaging unit affected by traffic excitation. In the third case, a power plant facility that is subjected to blast-induced vibration from an adjacent quarry is investigated. The last case involves the response analysis of a compressor foundation affected by the ground-transmitted vibration from another compressor situated on a different foundation within the same facility. To assess the level of seismic excitation at the site due to traffic on an adjacent roadway in the first two cases and to blasting activity in the third case, extensive "green field" ground vibration-monitoring programs were carried out. The ground accelerations due to traffic and blasting were measured and recorded for three directions simultaneously: a vertical and two orthogonal horizontal directions. The measurements with the most intense ground accelerations taken at the ground surface in the location of the future equipment foundation were selected as the final design acceleration time-history. A Fourier analysis approach was used to predict the response of the foundation to the ground-induced vibrations in the first three cases, and a frequency domain analysis was used in the last case.Key words: machine foundations, vibration, blasting, kinematic, soil-structure interaction.

Sign in / Sign up

Export Citation Format

Share Document