Time‐domain BEM for three‐dimensional site response analysis of topographic structures

Sohrabi-Bidar, Abdollah; Kamalian, Mohsen; Jafari, Mohammad Kazem

doi:10.1002/nme.2619

Cited by 20 publications

(12 citation statements)

References 36 publications

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“…For this purpose the BEMSA code The same as in Fig. 7, but considering the receiver that corresponds to NRN4 station (profile 2) (Sohrabi et al 2009), based on boundary element method (BEM), was used. The geometry of the hill and surroundings was modelled using 1,224 eight-nodes quadrilateral boundary elements (3,729 nodes) and 448 eight-nodes quadrilateral enclosing elements (1,289 nodes).…”

Section: D Site Response: Resultsmentioning

confidence: 99%

“…This paper is especially focused on the comparison between the experimental results, obtained applying both the single station technique (horizontal to vertical spectral ratio, HVSR, Lermo and Chavez-Garcia 1993) and the reference station technique (standard spectral ratio, SSR, Borcherdt 1970) and those coming from numerical modelling. The simulations were performed both in 2D configurations, using the code based on hybrid finite-boundary element method (Kamalian et al 2003) and in 3D configurations, using the BEMSA code (Sohrabi et al 2009) based on the boundary element method.…”

Section: Introductionmentioning

confidence: 99%

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Estimation of topographical effects at Narni ridge (Central Italy): comparisons between experimental results and numerical modelling

Lovati

Bakavoli

Massa

et al. 2011

Bull Earthquake Eng

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In the present work the seismic site response of Narni ridge (Central Italy) is evaluated by comparing experimental results and numerical simulations. The inhabited village of Narni is located in central Apennines at the top of a steep massive limestone ridge. From March to September 2009 the site was instrumented with 10 weak-motion stations, 3 of which located at the base of the ridge and 7 at the top. The velocimetric network recorded 642 events of ML up to 5.3 and hypocentral distance up to about 100 km. The great amount of data are related to the April 2009 L’Aquila sequence. The site response was analyzed using both reference (standard spectral ratio, SSR) and non reference spectral techniques (horizontal to vertical spectral ratio, HVSR). Moreover directional analyses were performed in order to evaluate the influence of the ridge orientation with respect to the selected source-site paths. In general the experimental results show amplification factors for frequencies between 4 and 5Hz for almost all stations installed along the crest. The SSR technique provides amplification factors up to 4.5 in a direction perpendicular to the main elongation of the ridge. The results obtained from the data analyses were used as a target for bidimensional and tridimensional numerical simulations, performed using a hybrid finite-boundary element method and a boundary element method for 2D and 3D modelling, respectively. In general, the results obtained through numerical simulation fit well the experimental data in terms of range of amplified frequencies, but they underestimate by a factor of about 2 the observed amplifications

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Section: D Site Response: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Estimation of topographical effects at Narni ridge (Central Italy): comparisons between experimental results and numerical modelling

Lovati

Bakavoli

Massa

et al. 2011

Bull Earthquake Eng

Self Cite

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“…Above-mentioned formulation was implemented in a computer code named as BEMSA (boundary element method for seismic analyses). Some examples including site response analysis of halfplane, valley and hill subjected to incident waves were solved to show the accuracy and efficiency of this implemented BE algorithm in carrying out site response analysis of topographic structures (Sohrabi-Bidar 2008;Sohrabi-Bidar et al 2009a, 2009b. A semi-spherical canyon has been subjected to vertically propagating compressional incident waves of the Ricker type.…”

Section: N U M E R I C a L F O R M U L At I O Nmentioning

confidence: 99%

“…However, they discretized the ground surface by assuming a collection of flat discs of homogenous size centred on the collocation point. Recently, Sohrabi‐Bidar (2008) and Sohrabi‐Bidar et al . (2009a,b) used a time domain 3‐D boundary element method for site response analysis of topographic structures considering both real spatial and temporal discretization.…”

Section: Introductionmentioning

confidence: 99%

Seismic response of 3-D Gaussian-shaped valleys to vertically propagating incident waves

Sohrabi-Bidar¹,

Kamalian

Jafari

2010

Geophysical Journal International

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S U M M A R YThis paper presents the results of a numerical parametric study on the seismic behaviour of 3-D Gaussian-shaped valleys subjected to vertically propagating incident waves. The medium was assumed to have a linear elastic constitutive behaviour. All calculations were executed in the time domain using the direct boundary element method. Representations of the amplification patterns of a valley were developed using both time-domain and frequency-domain responses. It was shown that wavelength and site geometry, including shape and dimension ratios and, to some extent, wave type are the key independent parameters governing valley amplification behaviour. Although 2-and 3-D valleys with similar shape ratios had similar characteristic periods, the 3-D valley had greater maximum deamplification potential and greater relative amplification potential along the valley.

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“…Chuhan and Chongbin [3] combined the finite and unlimited elements of the surface topography of valleys against SH shear invasive waves. Sohrabi and Kamalian [4] proposed the combination of finite element and boundary element methods and the development of a hybrid program to solve the seismic response problems of topographic complications of hills and valleys.…”

Section: Introductionmentioning

confidence: 99%

Seismic Response of Irregular Triangular Alluvial Valleys under Shear Waves Using Spectral Elements

Hosseinpour

Najafizadeh

2018

Civ Eng J

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The present study investigates seismic response problems of triangular uniform irregular alluvial valleys under shear waves using a finite element spectral method. Alluvial valleys; affect the shape and properties of alluvial materials on the response and seismic behavior of the valley surface due to the geometry conditions. Therefore this study aims to illustrate the plots and magnitude of amplification values for irregular alluvial valleys in a two-dimensional triangular manner, with the characteristics of homogeneous alluvial materials and different geometric characteristics. The analysis in the time domain was performed based on the finite element method of the spectral element (SFEM) using NASEM software, developed by Najafizadeh. The valleys are analyzed with the slope angles of 15, 30, 45 and 60 degrees on one side and in opposite directions with a slope of 45 degrees and with a maximum depth of 50 meters for the alluvial valley. The horizontal amplification curves in the alluvial valley's points from the analysis reach a maximum value at a given frequency, which can be an ideology for determining the frequency of irregular triangular alluvial valleys under different slope valley angles. The results of natural valley frequencies indicate that with decreasing slope of the valley, the natural frequency of the valley decreases, as well as amplification plots are related to the slope of the valley.

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Time‐domain BEM for three‐dimensional site response analysis of topographic structures

Cited by 20 publications

References 36 publications

Estimation of topographical effects at Narni ridge (Central Italy): comparisons between experimental results and numerical modelling

Estimation of topographical effects at Narni ridge (Central Italy): comparisons between experimental results and numerical modelling

Seismic response of 3-D Gaussian-shaped valleys to vertically propagating incident waves

Seismic Response of Irregular Triangular Alluvial Valleys under Shear Waves Using Spectral Elements

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