Site Response Analysis Using Downhole Array Recordings during the March 2011 Tohoku-Oki Earthquake and the Effect of Long-Duration Ground Motions

2013 ◽  
Vol 29 (1_suppl) ◽  
pp. 37-54 ◽  
Author(s):  
Byungmin Kim ◽  
Youssef M.A. Hashash
Keyword(s):  
Subduction Zone ◽  
Site Response ◽  
Soft Rock ◽  
Response Spectra ◽  
Response Analysis ◽  
Soil Behavior ◽  
Long Duration ◽  
Downhole Array ◽  
Downhole Arrays ◽  
Array Recordings

Downhole arrays provide enhanced understanding of dynamic soil behavior and site response. Historically, downhole array recordings have been available only for earthquakes with relatively limited durations. New recordings from a number of KiK-net downhole arrays during the 11 March 2011, Mw 9.0, subduction zone earthquake near the east coast of Honshu, Japan, allow us to investigate dynamic soil characteristics and site response due to long-duration subduction zone earthquakes. Using these recordings, we perform one-dimensional site response analyses to evaluate the applicability of commonly used analysis approaches under long-duration earthquakes. We find that site response analyses capture key features of measured surface response spectra particularly at soft rock/stiff soil sites subject to long-duration motion. However, at softer soil sites, it appears that the modulus reduction is overestimated and site-specific characterization is needed.

Improved Approach for Modeling Nonlinear Site Response of Highly Strained Soils: Case Study of the Service Hall Array in Japan

2016 ◽  
Vol 32 (2) ◽  
pp. 1055-1074 ◽  
Author(s):  
Ramin Motamed ◽  
Kevin Stanton ◽  
Ibrahim Almufti ◽  
Kirk Ellison ◽  
Michael Willford
Keyword(s):  
Nuclear Power ◽  
Site Response ◽  
Free Field ◽  
Peak Strength ◽  
Response Analysis ◽  
Soil Behavior ◽  
Backbone Curve ◽  
Ground Response Analysis ◽  
Nonlinear Site Response ◽  
Highly Strained

A nonlinear ground response analysis is conducted for the Niigata-ken Chuetsu-oki earthquake recorded at a free-field vertical array near the Kashiwazaki-Kariwa Nuclear Power Plant in Japan. A bidirectional site response analysis is carried out using LS-DYNA which allows user defined stress-strain relationships to dictate soil behavior subjected to dynamic loading. Dynamic soil behavior is characterized using a two-stage hyperbolic backbone curve implemented with modifications to consider the peak strength of soil layers as well as the strain at which the peak strength is fully mobilized. The effects of bidirectional input motions, strain rate, and the shape of the shear modulus degradation curves are investigated, and it is demonstrated that each factor can have a significant influence on the results.

scholarly journals A Site-Specific Response Analysis: A Case Study in Hanoi, Vietnam

2020 ◽  
Vol 10 (11) ◽  
pp. 3972 ◽  
Author(s):  
Van-Quang Nguyen ◽  
Muhammad Aaqib ◽  
Duy-Duan Nguyen ◽  
Nguyen-Vu Luat ◽  
Duhee Park
Keyword(s):  
Site Response ◽  
Response Spectra ◽  
Response Analysis ◽  
Specific Response ◽  
Site Class ◽  
Soil Stiffness ◽  
Design Spectrum ◽  
Class D ◽  
The Difference ◽  
A Site

A series of one-dimensional (1-D) site response analyses were performed using the nonlinear (NL) and equivalent linear (EQL) approaches to assess the applicability of the Vietnamese earthquake-resistance design code TCVN 9386: 2012. Six soil profiles were selected from three districts in Hanoi (Vietnam). A number of ground motions compatible with the rock design spectrum were used as input for carrying out analyses. The results highlight that the calculated response is higher than the design spectrum for site class C and lower for site class D. The normalized response spectra of the EQL approach results are higher than those of the NL approach. Moreover, the peak ground accelerations at the surface from EQL analyses are greater than those of the NL method because the latter generates a higher amount of nonlinearity. The results from the NL approach also illustrate that the deamplification phenomenon occurs in the soft soils of the Hanoi region (e.g., soil profile P3 and P5 of site class D). Additionally, the shear strains calculated from the NL method are closely matched with those from the EQL method, the difference between them increasing with a decrease in soil stiffness.

Evaluation of the effect of depth to bedrock on seismic amplification phenomena

2020 ◽  
Author(s):  
gaetano falcone ◽  
giuseppe naso ◽  
stefania fabozzi ◽  
federico mori ◽  
massimiliano moscatelli ◽  
...  
Keyword(s):  
Seismic Waves ◽  
Site Response ◽  
Soft Soil ◽  
Free Field ◽  
Response Spectra ◽  
Maximum Depth ◽  
Response Analysis ◽  
Local Conditions ◽  
Seismic Amplification ◽  
Bedrock Depth

<p>When an earthquake occurs, the propagation of the seismic waves is conditioned by local conditions, e.g., depth to seismic bedrock and impedance ratio between soft soil and seismic bedrock. Bearing in mind that the maximum depth of site prospections generally does not extend up to seismic bedrock depth, a parametric study was carried out with reference to ideal case studies in order to investigate the effect on local seismic amplification of the depth to bedrock.</p><p>The results are presented in terms of charts of amplification factors (i.e., ratio of integral quantities referred to free-field and reference response spectra) and minimum depth to investigate vs building type. These charts will allow defining the thickness of the cover deposit that should be characterised in terms of geophysical and geotechnical parameters in order to perform seismic site response analysis according to a precautionary approach, in areas where depth to seismic bedrock is higher than conventional maximum depth of site surveys.</p>

Study on Differences in Floor Response Spectra due to the Seismic Input Approach

2016 ◽  
Author(s):  
Jana Sue Bochert ◽  
Henry Schau ◽  
Timo Schmitt
Keyword(s):  
Wave Propagation ◽  
Site Response ◽  
Response Spectra ◽  
Response Analysis ◽  
Ground Response ◽  
Soil Layers ◽  
Seismic Input ◽  
Floor Response Spectra ◽  
Propagation Analysis ◽  
Different Depths

In this paper the differences of floor response spectra (FRS) resulting from different ground response spectra are discussed. These spectra include the site effects which are quantified via site response analysis. This response is generated by wave propagation from the base rock through the overlying soil layers to the surface. The influences of the different layers and the corresponding dynamic soil properties are considered by using wave propagation analysis. The paper then discusses the results obtained from seismic input at different depths conditions. Similar results might be expected, because the depth of the input spectra is adjusted for each layer. However, in comparing the floor response spectra of these calculations, significant differences are observed and therefore interpreted. The paper is completed with the explanation of these significant differences and also with comparable floor response spectra.

scholarly journals KELAS SOIL DAERAH SEKITAR RENCANA TAPAK REAKTOR DAYA EKSPERIMENTAL (RDE) SERPONG DARI DATA MIKROTREMOR

2015 ◽  
Vol 17 (1) ◽  
pp. 57
Author(s):  
Marjiyono Marjiyono ◽  
Hadi Suntoko ◽  
A. Soehaimi ◽  
Yuliastuti Yuliastuti ◽  
H. Syaeful
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Velocity Structure ◽  
Power Reactor ◽  
Site Response ◽  
Soft Rock ◽  
Response Analysis ◽  
Soil Class ◽  
Single Station

ABSTRAK KELAS SOIL DAERAH SEKITAR RENCANA TAPAK REAKTOR DAYA EKSPERIMENTAL (RDE) SERPONG DARI DATA MIKROTREMOR. Karakteristik geologi permukaan memegang peranan penting dalam analisis respon gelombang di suatu wilayah.  Sehubungan dengan rencana pembangunan Reaktor Daya Eksperimental (RDE) di Serpong, telah dilakukan pemodelan kondisi bawah permukaan dari kombinasi data mikrotremor array dan single station. Pengukuran mikrotremor array dilakukan di 9 lokasi, sedangkan single station di 90 lokasi yang tersebar pada radius ± 1 km di sekitar tapak RDE. Model bawah permukaan yang berupa struktur kecepatan gelombang geser selanjutnya dijadikan dasar untuk menghitung nilai Vs30 di daerah tersebut. Hasil klasifikasi soil berdasarkan nilai Vs30 menunjukkan kelas soil untuk wilayah sekitar tapak RDE secara umum terdiri atas kelas SD (soil menengah) dan SC (batuan lunak). Lokasi rencana tapak sendiri berada dalam wilayah kelas soil SD. Kata kunci : kelas soil, kecepatan gelombang geser, mikrotremor, tapak RDE, Vs30.   ABSTRACT SOIL CLASS AROUND THE SERPONG EXPERIMENTAL POWER REACTOR (EPR) SITE PLAN BASE ON MICROTREMOR DATA. Surface geological characteristics has an important role on site response analysis in a region. In regard with experimental power reactor (EPR) construction plan in Serpong, the subsurface modeling from combination array and single station microtremor data was done. The array and single station microtremor measurement were performed in 9 and 90 sites, respectively, at ± 1 km radius around the EPR site plan. The Vs30 value was calculated from shear wave velocity structure around the investigated area. The soil classification based on Vs30 in the investigated area generally consists of SD (medium soil) and SC (soft rock) class. The EPR site plan its self in the SD class region. Keyword : soil class, shear wave velocity, microtremor, EPR site, Vs30

Site Response Analysis for “Side” Soil Profiles

2020 ◽  
pp. 11-17
Author(s):  
Alexander Tyapin ◽  
Nikita Antonov
Keyword(s):  
Site Response ◽  
Time History ◽  
Response Spectra ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Soil Profiles ◽  
Seismic Excitations ◽  
Control Motion ◽  
The Difference ◽  
Upper Boundary

The authors suggest a new procedure of Site Response Analysis (SRA) for the so-called “side” (or additional) soil profiles – Low Boundary (LB) and Upper Boundary (UB). Standards require the analyses of these profiles in addition to the Best Estimate profile (BE) to account for the uncertainty in the input data about soil properties. The authors suggest stopping using the same input time history for all three profiles as a control motion at the surface, because it corresponds to the different physical seismic excitations coming form the depth. This is not in linewith the ideology of Standards. Instead the authors suggest using the same time history as a control motion at the outcropped surface of the underlying half-space. This is also not completely correct, because for these three profiles (BE, UB and LB) the underlying half-spaces are also different. However, due to the physical considerations if all half-spaces are stiff enough, the error should not be so important. The effect of the proposed change is demonstrated on a particular site. The changes in the velocity and damping profiles have proved to be negligible, but the difference in the resulting response spectra at the outcropped surface of the foundation mat has proved to be significant. Generally, the response spectra for the “side” profiles came closer to spectrum for the BE profile. This result reflects the real world logic.

Evaluation of One-Dimensional Multi-Directional Site Response Analyses Using Geotechnical Downhole Array Data in California and Japan

2018 ◽  
Vol 34 (1) ◽  
pp. 349-376 ◽  
Author(s):  
Gangjin Li ◽  
Ramin Motamed ◽  
Stephen Dickenson
Keyword(s):  
Site Response ◽  
Ground Motions ◽  
Soil Column ◽  
Response Analysis ◽  
Engineering Practice ◽  
Backbone Curve ◽  
One Dimensional ◽  
Strain Behavior ◽  
Linear Elastic ◽  
Downhole Array

This study presents a comprehensive investigation of one-dimensional (1-D) site response analysis (SRA) to predict the dynamic response of soil deposits under earthquake loading utilizing the recordings at selected borehole arrays. Seven instrumented downhole arrays in California and Japan were studied using 41 recorded ground motions that cover a broad range of intensities. The arrays were initially assessed in terms of effectiveness of 1-D SRA using taxonomy screening. Furthermore, LS-DYNA, an advanced Finite Element (FE) program, was employed to develop the 1-D soil column models for the SRA of these arrays. The soil stress-strain behavior was characterized with three different models including one linear elastic and two nonlinear backbone curve formulations. All predictions were compared to the measured ground motions to quantify the model biases and uncertainties. Lastly, the practical limitations of 1-D SRA models considered herein are identified, and recommendations are provided to assess the usefulness of the predictions in engineering practice.

scholarly journals Combined Geophysical and Geotechnical Approaches for Microzonation Studies in Hispaniola Island

Geosciences ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 336
Author(s):  
Belvaux Myriam ◽  
Meza-Fajardo Kristel ◽  
Abad Jaime ◽  
Bertil Didier ◽  
Roullé Agathe ◽  
...  
Keyword(s):  
Site Response ◽  
Response Spectra ◽  
Greater Antilles ◽  
Response Analysis ◽  
Main Stage ◽  
Specific Response ◽  
Santo Domingo ◽  
Seismogenic Fault ◽  
Geotechnical Data

In this paper, we describe recent studies for the geophysical and geomechanical characterization of soils in Hispaniola (Greater Antilles), an island threatened by the eventual rupture of major seismogenic fault systems. The investigations were performed for four different cities settled on complex geological formations in Haiti (Cap-Haïtien, Port-au-Prince) and the Dominican Republic (Santo Domingo, Santiago de los Caballeros). We present the complete methodology we implemented for mapping zones of homogeneous seismic response and for microzonation studies, but each main stage of investigation is described as it was conducted in one or two cities. Therefore, first we present our site-characterization technique applied to Santo Domingo and Santiago de los Caballeros, which is based on geotechnical data, geophysical multichannel analysis of surface waves, and ambient-noise recordings. Then we present the site-response analysis through numerical analysis with nonlinear soil models that we performed for the city of Cap-Haïtien. Finally, we describe the amplification factors for site-specific response spectra that we derived for the microzonation of Port-au-Prince. We argue for the implementation of a multidisciplinary approach built upon complementary field geological, geophysical, and geotechnical data rather than solely depending on geophysical measures for the characterization of VS30. In addition, we explore the compatibility of the soil classes recommended by the International Building Code (IBC) in the context of local seismic amplification.

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