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.

scholarly journals Assessment of the Design Spectrum with Aggravation Factors by 2D Nonlinear Numerical Analyses: A Case Study in Gemlik Basin, Turkey

2021 ◽  
Author(s):  
BİLAL ÖZASLAN ◽  
Recep Iyisan ◽  
Emre Murat Hasal ◽  
Hadi Khanbabazadeh ◽  
Hiroaki Yamanaka
Keyword(s):  
Seismic Waves ◽  
Plastic Material ◽  
Site Response ◽  
Response Spectra ◽  
Considerable Effect ◽  
Design Spectrum ◽  
The North ◽  
Basin Effects ◽  
Stratification Effect ◽  
A Site

Abstract The response spectra of multidimensional analyses are compared with the one-dimensional (1D) local models to couple the irregular soil stratification effect in a site. In recent studies, the surface motion spectra ratios of 2D/1D or 3D/1D are defined as spectral aggravation factors for each region in a site. Particularly in alluvial basins, where the soil media is typically formed by fault ruptures or topographic depressions filled with sediments, the inclination of the rock outcrop in the edge of the basin has a considerable effect on the site response, and such effect has not yet been taken into consideration of recent seismic building codes and general engineering applications. In this study, the natural alluvial basin near the North Anatolian Fault in Gemlik, Maramara Region, Turkey, was investigated by 40 seismic site tests and 4 validation borings. The 2D and 1D nonlinear response history analyses in north-south and east-west directions of the Gemlik basin were performed by numerical model on finite difference scheme considering nonlinear elasto-plastic material behaviors and geometric discontinuities. 22 strong ground motions recorded on rock site are excited vertically as SH waves. The numerical results exhibited the narrow basin effects are derived not only by reflection, refraction, and shifting behavior but also by focusing and superposition of the seismic waves propagating from both opposite basin edges. As a result, the site-specific spectral aggravation factors, SAF2D/1D defined by the ratio between the 2D and 1D acceleration response spectra for each period and any location on the site, were proposed for the Gemlik basin. The variations of the aggravation factors were observed as increasing values to 1.2–2.2 on the near edge and basin center.

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.

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.

scholarly journals Design Response Spectra Based on Earthquake Hazard Maps and Specific Soil Properties at Indonesian Ports According to SNI 1726 2019

2021 ◽  
Vol 17 (1) ◽  
pp. 41-54
Author(s):  
Christino Boyke Surya Permana
Keyword(s):  
Site Response ◽  
Response Spectrum ◽  
Earthquake Hazard ◽  
Response Spectra ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Spectral Acceleration ◽  
Hazard Maps ◽  
The Difference ◽  
S Period

Indonesia has a new seismic code, namely SNI 1726 2019 (SNI 2019). It is developed based on the 2017 Indonesian Earthquake Source, Hazard Maps, and ASCE 7-16. This paper is intended to explain the procedure for calculating response spectrum according to SNI 1726 2019, at ten ports located in Indonesia. The results are then verified with the software RSA2019.  Furthermore, it will be compared to SNI 1726 2012 (SNI 2012) to see the difference in spectral acceleration value (Sa). The result presents that the ports located in Sorong and Banggai have the highest Sa, whereas the port in Banjarmasin has the smallest value. Port in Surabaya and Tuban have nearly the same Sa due to their close location, while Banyuwangi has a Sa value slightly above them. The ports in Padang, Lampung, and Penajam must use a specific site response analysis to determine the design response spectra, which is not discussed in this paper. The comparison with SNI 2012 shows that the response spectra of SNI 2019 have a higher Sa than SNI 2012. However, in some areas such as Tuban and Sorong, the Sa of SNI 2012 at 0.1 to 0.6 s period are larger than SNI 2019.  

scholarly journals Design Earthquake Response Spectrum Affected by Shallow Soil Deposit

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Dong-Kwan Kim ◽  
Hong-Gun Park ◽  
Chang-Guk Sun
Keyword(s):  
Soil Depth ◽  
Site Response ◽  
Response Spectrum ◽  
Soft Soil ◽  
Response Spectra ◽  
Earthquake Response ◽  
Ground Acceleration ◽  
Site Class ◽  
Shallow Soil ◽  
Short Period

Site response analyses were performed to investigate the earthquake response of structures with shallow soil depth conditions in Korea. The analysis parameters included the properties of soft soil deposits at 487 sites, input earthquake accelerations, and peak ground-acceleration levels. The response spectra resulting from numerical analyses were compared with the design response spectra (DRS) specified in the 2015 International Building Code. The results showed that the earthquake motion of shallow soft soil was significantly different from that of deep soft soil, which was the basis of the IBC DRS. The responses of the structures were amplified when their dynamic periods were close to those of the site. In the case of sites with dynamic periods less than 0.4 s, the spectral accelerations of short-period structures were greater than those of the DRS corresponding to the site class specified in IBC 2015. On the basis of these results, a new form of DRS and soil factors are proposed.

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.

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 Seismological analyses of the seismic microzonation of 138 municipalities damaged by the 2016–2017 seismic sequence in Central Italy

2019 ◽  
Vol 18 (12) ◽  
pp. 5553-5593 ◽  
Author(s):  
E. Priolo ◽  
F. Pacor ◽  
D. Spallarossa ◽  
G. Milana ◽  
G. Laurenzano ◽  
...  
Keyword(s):  
Site Response ◽  
Central Italy ◽  
Response Spectra ◽  
Quantitative Information ◽  
Seismic Microzonation ◽  
Specific Response ◽  
Civil Protection ◽  
Site Specific ◽  
Resonance Frequencies ◽  
Short Period

Abstract This paper describes the seismological analyses performed within the framework of the seismic microzonation study for the reconstruction of 138 municipalities damaged by the 2016–2017 sequence in Central Italy. Many waveforms were recorded over approximately 15 years at approximately 180 instrumented sites equipped with permanent or temporary stations in an area that includes all the damaged localities. Site response was assessed using earthquake and noise recordings at the selected stations through different parameters, such as spectral amplification curves, fundamental resonance frequencies, site-specific response spectra, and average amplification factors. The present study was a collaboration of many different institutions under the coordination of the Italian Center for Seismic Microzonation and its applications. The results were homogenized and gathered into site-specific forms, which represent the main deliverable for the benefit of Italian Civil Protection. It is remarkable that the bulk of this study was performed in a very short period (approximately 2 months) to provide quantitative information for detailed microzonation and future reconstruction of the damaged municipalities.

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