scholarly journals Seismic Ground Response Analysis of Input Earthquake Motion and Site Amplification Factor at KUET

2021 ◽  
pp. 45-54
Author(s):  
Sonia Akter
Keyword(s):  
Ground Motion ◽  
Shear Wave Velocity ◽  
Amplification Factor ◽  
Site Response ◽  
Site Amplification ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Kobe Earthquake ◽  
Earthquake Motion

Ground motion is the movement of the earth's surface due to explosions or the propagation of seismic waves. In the seismic design process, ground response analysis evaluates the impact of local soil conditions during earthquake shaking. However, it is difficult to determine the dynamic site response of soil deposits in earthquake hazard-prone areas. Structural damage has a great influence on the selection of input ground motion, and in this study, the importance of bedrock motion upon the response of soil is highlighted. The specific site response analysis is assessed through “DEEPSOIl" software with an equivalent linear analysis method. Furthermore, four input motions including Kobe, LomaGilroy, Northridge, and Chi-Chi were selected to obtain normalized response spectra. This study aims to obtain the site amplification of ground motion, peak spectral acceleration (PSA), and maximum peak ground acceleration (PGA) based on shear wave velocity from the detailed site-specific analysis of Bangabandhu Sheikh Mujibor Rahman hall at Khulna University of Engineering & Technology. The maximum shear wave velocity obtained was 205 m/s while the amplification factor varied from 4.01 (Kobe) to 1.8 (Northridge) for rigid bedrock properties. Furthermore, the Kobe earthquake produced the highest (4.3g) PSA and the Northridge earthquake produced the lowest (1.08g) PSA for bedrock, with Vs=205 m/s. The surface PGA values were acquired in the range of 0.254g (Northridge) to 0.722g (Kobe), and the maximum strain values for Kobe earthquakes were in the range of 0.016 to .303. Therefore, the surface acceleration values were very high (>0.12g) for the Kobe earthquake motion.

scholarly journals Evaluation of Seismic Site Amplification Using 1D Site Response Analyses at Ba Dinh Square Area, Vietnam

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ngoc-Long Tran ◽  
Muhammad Aaqib ◽  
Ba-Phu Nguyen ◽  
Duy-Duan Nguyen ◽  
Viet-Linh Tran ◽  
...  
Keyword(s):  
Site Response ◽  
Ground Motions ◽  
Site Amplification ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Ground Acceleration ◽  
Site Specific ◽  
Design Spectrum ◽  
Equivalent Linear

This study presents a case study on ground response analysis of one of the important cultural heritages in Hanoi, Vietnam. One-dimensional nonlinear and equivalent linear site response analyses which are commonly applied to solve the problem of seismic stress wave propagation are performed at the Ba Dinh square area. A measured in-situ shear wave velocity profile and corresponding geotechnical site investigation and laboratory test data are utilized to develop the site model for site-specific ground response analysis. A suite of earthquake records compatible with Vietnamese Design Code TCVN 9386: 2012 rock design spectrum is used as input ground motions at the bedrock. A few concerns associated with site-specific ground response evaluation are analyzed for both nonlinear and equivalent linear procedures, including shear strains, mobilized shear strength, and peak ground acceleration along with the depth. The results show that the mean maximum shear strains at any soil layer are less than 0.2% in the study area. A deamplification portion within the soil profile is observed at the layer interface with shear wave velocity reversal. The maximum peak ground acceleration (PGA) at the surface is about 0.2 g for equivalent linear analysis and 0.16 g for nonlinear analysis. The ground motions are amplified near the site natural period 0.72 s. The soil factors calculated in this study are 1.95 and 2.07 for nonlinear and equivalent linear analyses, respectively. These values are much different from the current value of 1.15 for site class C in TCVN 9386: 2012. A comparison of calculated response spectra and amplification factors with the local standard code of practice revealed significant discrepancies. It is demonstrated that the TCVN 9386: 2012 soil design spectrum is unable to capture the calculated site amplification in the study area.

Seismic Ground Response Analysis of Some Typical Sites of Guwahati City

2013 ◽  
Vol 4 (1) ◽  
pp. 83-101 ◽  
Author(s):  
Shiv Shankar Kumar ◽  
A. Murali Krishna
Keyword(s):  
Ground Motion ◽  
Amplitude Ratio ◽  
Response Spectrum ◽  
Strong Motion ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Ground Acceleration ◽  
Surface Level ◽  
Guwahati City

In this study, one dimensional equivalent–linear ground response analyses were performed for some typical sites in the Guwahati city, India. Six bore locations covering about 250 km2 area of the city were considered for the analyses. As the strong motion significantly influences the ground response, seven different recorded ground motions, varying in magnitude (6.1 to 8.1) and other ground motion parameters, were adopted. Seismic site analyses were carried out for all layers of borelogs using all the seven earthquakes. Results are presented in terms of surface acceleration histories, strain and shear stress ratio variation, response spectrum, Fourier amplitude ratio versus frequency. The results indicate that accelerations were amplified the most at the surface level. The range of peak ground acceleration (PGA) values obtained at the ground surface is about 0.2 g to 0.79 for a range of PGA considered at bedrock level (rigid half space at bottom of borelog) of 0.1 g to 0.34 g. The Fourier amplifications of ground motion at surface are in the range of 4.14 – 8.99 for a frequency band of 1.75 Hz to 3.13 Hz. The maximum spectral acceleration at six locations varies in the range of 1.0 g – 4.71 g for all the seven earthquakes. The study clearly demonstrated the role for site effect and the type of ground motion on the ground response. For a given earthquake motion, amplification factors at surface level change by almost about 20% to 70% depending on local site conditions.

scholarly journals Parametric Study of Local Site Response for Bedrock Ground Motion to Earthquake in Phuentsholing, Bhutan

2020 ◽  
Vol 12 (13) ◽  
pp. 5273 ◽  
Author(s):  
Karma Tempa ◽  
Raju Sarkar ◽  
Abhirup Dikshit ◽  
Biswajeet Pradhan ◽  
Armando Lucio Simonelli ◽  
...  
Keyword(s):  
Shear Wave ◽  
Ground Motion ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Soil Profile ◽  
Parametric Study ◽  
Site Response ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Geophysical Study

Earthquakes, when it comes to natural calamities, are characteristically devastating and pose serious threats to buildings in urban areas. Out of multiple seismic regions in the Himalayas, Bhutan Himalaya is one that reigns prominent. Bhutan has seen several moderate-sized earthquakes in the past century and various recent works show that a major earthquake like the 2015 Nepal earthquake is impending. The southwestern city of Bhutan, Phuentsholing is one of the most populated regions in the country and the present study aims to explore the area using geophysical methods (Multispectral Analysis of Surface Waves (MASW)) for understanding possibilities pertaining to infrastructural development. The work involved a geophysical study on eight different sites in the study region which fall under the local area plan of Phuentsholing City. The geophysical study helps to discern shear wave velocity which indicates the soil profile of a region along with possible seismic hazard during an earthquake event, essential for understanding the withstanding power of the infrastructure foundation. The acquired shear wave velocity by MASW indicates visco-elastic soil profile down to a depth of 22.2 m, and it ranged from 350 to 600 m/s. A site response analysis to understand the correlation of bedrock rigidness to the corresponding depth was conducted using EERA (Equivalent-linear Earthquake Site Response Analysis) software. The amplification factors are presented for each site and maximum amplification factors are highlighted. These results have led to a clear indication of how the bedrock characteristics influence the surface ground motion parameters for the corresponding structure period. The results infer that the future constructional activity in the city should not be limited to two- to five-story buildings as per present practice. Apart from it, a parametric study was initiated to uncover whatever effects rigid bedrock has upon hazard parameters for various depths of soil profile up to 30 m, 40 m, 60 m, 80 m, 100 m, 120 m, 140 m, 160 m, 180 m and 200 m from the ground surface. The overriding purpose of doing said parametric study is centered upon helping the stack holders who can use the data for future development. Such a study is the first of its kind for the Bhutan region, which suffers from the unavailability of national seismic code, and this is a preliminary step towards achieving it.

κ0 for soil sites: Observations from KiK-net sites and their use in constraining small-strain damping profiles for site response analysis

2019 ◽  
Vol 36 (1) ◽  
pp. 111-137 ◽  
Author(s):  
Boqin Xu ◽  
Ellen M Rathje ◽  
Youssef Hashash ◽  
Jonathan Stewart ◽  
Kenneth Campbell ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Site Response ◽  
Strong Motion ◽  
Small Strain ◽  
Site Amplification ◽  
Site Response Analysis ◽  
Response Analysis ◽  
One Dimensional

Small-strain damping profiles developed from geotechnical laboratory testing have been observed to be smaller than the damping inferred from the observed site amplification from downhole array recordings. This study investigates the high-frequency spectral decay parameter ( κ0) of earthquake motions from soil sites and evaluates the use of κ0 to constrain the small-strain damping profile for one-dimensional site response analysis. Using data from 51 sites from the Kiban-Kyoshin strong motion network (KiK-net) array in Japan and six sites from California, a relationship was developed between κ0 at the surface and both the 30-m time-averaged shear wave velocity ( V s30) and the depth to the 2.5 km/s shear wave velocity horizon ( Z2.5). This relationship demonstrates that κ0 increases with decreasing V s30 and increasing Z2.5. An approach is developed that uses this relationship to establish a target κ0 from which to constrain the small-strain damping profile used in one-dimensional site response analysis. This approach to develop κ0-consistent damping profiles for site response analysis is demonstrated through a recent site amplification study of Central and Eastern North America for the NGA-East project.

scholarly journals The Use of Ground Motion Parameters to identify the Liquefaction during a Strong Earthquake in Northern Thailand

2021 ◽  
Vol 27 (1) ◽  
pp. 1-8
Author(s):  
Lindung Zalbuin Mase
Keyword(s):  
Pore Pressure ◽  
Amplification Factor ◽  
Pressure Ratio ◽  
Excess Pore Pressure ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Northern Thailand ◽  
Motion Parameters ◽  
Excess Pore

This paper presents a ground response analysis to simulate the liquefaction phenomenon during the 2011 Tarlay Earthquake in northern Thailand. The site investigation data and geophysical measurements on 7 sites in northern Thailand were collected. The multi-springs element model was implemented in finite element ground response analysis. Several parameters, such as peak ground acceleration, peak ground velocity, amplification factor, excess pore pressure ratio, were observed. Furthermore, the correlation from the ground motion parameters was generated to estimate liquefaction potential, which was represented by excess pore pressure ratio. The result showed that the excess pore pressure ratio was relatively well correlated with several ground parameters, such as amplification factor, velocity-acceleration ratio, and factor of safety against liquefaction. The results could be also used for the engineering practice in predicting liquefaction potential in Northern Thailand.

scholarly journals Reliability on ProSHAKE 2.0 in the Assessment of One Dimensional Ground Response Analysis through Verification Example

2019 ◽  
Vol 8 (4S2) ◽  
pp. 56-59
Keyword(s):  
Maximum Amplitude ◽  
Response Spectra ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Peak Displacement ◽  
Earthquake Motion ◽  
Soil Deposits ◽  
Time Histories ◽  
Frequency Domain Approach

It is understood from the recent destructive earthquakes, topography, nature of the bedrock and geometry of the soil deposits are the prime factors that made modifications to the underlying earthquake motion. The influence of such confined soil states on the strong earthquake motion plays a significant task in accessing the uniqueness of ground action. In this paper, the response of the soil layers to the earthquake action of the bedrock directly under it is determined. The analysis is done through frequency domain approach. Pro-shake software 2.0 is used to arrive the reliability of the ground response study. A wide variety of output parameters such as time histories of acceleration, velocity, displacement, shear stress, shear strain, response spectra and maximum amplitude of various parameters with depth are plotted and the other scalar parameters such as peak acceleration, peak velocity, peak displacement, RMS acceleration, arias intensity, predominant period and bracketed duration was computed.

Dynamic Characterization and Site Response Studies for an Offshore Site Based on Detailed Geotechnical Tests

2015 ◽  
Vol 6 (1) ◽  
pp. 50-80
Author(s):  
T. G. Sitharam ◽  
Naveen James ◽  
Monalisha Nayak
Keyword(s):  
Ground Motion ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Site Characterization ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Undisturbed Soil ◽  
Design Response Spectrum ◽  
Laboratory Test Results

The uniqueness of this paper is large amount of field test data and in addition laboratory test results on undisturbed soil samples, has been analyzed to capture the effect of local site condition and material properties of overlying soil on seismic ground motion characteristics. This study involves the seismic site characterization and ground response analysis of an offshore site in Western Yemen. From the results of field and laboratory tests, dynamic properties such as shear modulus and damping ratio for a very low to high strain levels was determined and site characterization was also carried out. Using seismic cone penetration test (SCPT) data a new correlation has been developed to predict the shear wave velocity. Synthetic ground motion was generated using Boore's stochastic modeling technique for ground response analysis and peak ground acceleration (PGA) was evaluated and presented in the paper. This paper also presents a site specific design response spectrum based on Eurocode, corresponding to 475 and 2500 year return period.

A Site Specific Study on Evaluation of Design Ground Motion Parameters

2010 ◽  
Vol 1 (1) ◽  
pp. 1-24 ◽  
Author(s):  
A. Boominathan ◽  
S. Krishna Kumar
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Site Specific ◽  
Specific Analysis ◽  
A Site

Design ground motions are usually developed by one of the two approaches: site-specific analyses or from provisions of building codes. Although contemporary codes do consider approximately the site effects, they provide more conservative estimates. Hence it is preferred to carry out site specific analysis which involves both the seismic hazard analysis and ground response analysis. This article presents a site specific analysis for a seismically vulnerable site near Ahmedabad, Gujarat. The seismic hazard analysis was carried out by DSHA approach considering seismicity and seismotectonics within 250km radius. The site is predominantly characterized by deep stiff sandy clay deposits. Extensive shear wave velocity measurement by cross hole test is used for site classification and ground response analysis. The ground response analysis was carried out by equivalent linear approach using SHAKE2000. It is found that the deep stiff soil site considered is found to amplify the ground motion. The site specific response spectra obtained from RRS analysis is compared with the codal provision which reveals high spectral acceleration in site specific spectra for mid period range.

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