Consistent site-response/soil-structure interaction analysis and evaluation

Ostadan, Farhang; Kennedy, R.P.

doi:10.1016/j.nucengdes.2013.08.009

Cited by 7 publications

(13 citation statements)

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“…The first area of action in WP4 dealt with the development and the consolidation of the computational chain in probabilistic and sensitivity analysis, through establishment of meta-models (to increase numerical performance, because we have to cope with the exploration of wide ranges of variability) and the calculation of fragility curves by bestestimate simulations. The use of neural network regression meta-models has been evaluated (Ostadan and Kennedy 2014). The efficiency of this approach for applications is sensitive to the modeling choices, and in particular the training algorithm might need large computational time to produce adequate precision.…”

Section: Main Scientific Advances From Wp4 Actionsmentioning

confidence: 99%

Main Achievements of the Multidisciplinary SINAPS@ Research Project: Towards an Integrated Approach to Perform Seismic Safety Analysis of Nuclear Facilities

Berge‐Thierry¹,

Voldoire²,

López-Caballero³

et al. 2019

Pure Appl. Geophys.

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This contribution provides an overview of the SINAPS@ French research project and its main achievements. SINAPS@ stands for ''Earthquake and Nuclear Facility: Improving and Sustaining Safety'', and it has gathered the broad research community together to propose an innovative seismic safety analysis for nuclear facilities. This five-year project was funded by the French government after the 2011 Japanese Tohoku large earthquake and associated tsunami that caused a major accident at the Fukushima Daïchi nuclear power plant. Soon after this disaster, the international community involved in nuclear safety questioned the current methodologies used to define and to account for seismic loadings for nuclear facilities during the design and periodic assessment review phases. Within this framework, worldwide nuclear authorities asked nuclear licensees to perform 'stress tests' to estimate the capacity of their existing facilities for sustaining extreme seismic motions. As an introduction, the French nuclear regulatory framework is presented here, to emphasize the key issues and the scientific challenges. An analysis of the current French practices and the need to better assess the seismic margin of nuclear facilities contributed to the shaping of the scientific roadmap of SINAPS@. SINAPS@ was aimed at conducting a continuous analysis of completeness and gaps in databases (for all data types, including geology, seismology, site characterization, materials), of reliability or deficiency of models available to describe physical phenomena (i.e., prediction of seismic motion, site effects, soil and structure interactions, linear and nonlinear wave propagation, material constitutive laws in the nonlinear domain for structural analysis), and of the relevance or weakness of methodologies used for seismic safety assessment. This critical analysis that confronts the methods (either deterministic or probabilistic) and the available data in terms of the international state of the art systematically addresses the uncertainty issues. We present the key results achieved in SINAPS@ at each step of the full seismic analysis, with a focus on uncertainty identification, quantification, and propagation. The main lessons learned from SINAPS@ are highlighted. SINAPS@ promotes an innovative integrated approach that is consistent with Guidelines #22, as recently published by the French Nuclear Safety Authority (Guidelines ASN #22 2017), and opens the perspectives to improve current French practice.

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Section: Main Scientific Advances From Wp4 Actionsmentioning

confidence: 99%

Main Achievements of the Multidisciplinary SINAPS@ Research Project: Towards an Integrated Approach to Perform Seismic Safety Analysis of Nuclear Facilities

Berge‐Thierry¹,

Voldoire²,

López-Caballero³

et al. 2019

Pure Appl. Geophys.

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“…It was not until recently in 2016, the ASCE/SEI 7 standard, 21 one of the key documents for building design in the United States, updated the specification on vertical ground motion assessment based on recent studies of V/H ratios to reflect the important frequency‐dependent relationship between the vertical and horizontal motions. This is considered an expedient approach, however, not only because of the practical limitations in the empirical V/H ratios to represent attenuation relations that may differ from the horizontal component, resulting in additional uncertainties, 22 but also the difficulty in applying it to site‐specific ground motion procedures and soil‐structure interaction analysis that are required for critical infrastructures 23 . To obtain site‐specific ground motions, 1D SRA is typically performed in current practice.…”

Section: Introductionmentioning

confidence: 99%

“…This approach assumes that the seismic waves reaching the site are nearly vertically propagating due to wave refraction through the upper crustal velocity gradient and the local soil is composed of stacked horizontal layers without lateral heterogeneity. These assumptions, which were introduced during the pioneering works in the 1950s-1970s [1][2][3] and are collectively referred to as the "1D assumption" in this article, are now broadly adopted in various aspects of earthquake engineering, for example, seismic hazard calculation, 4 site response calibration, 5 and soil-structure interaction, 6 among others.…”

mentioning

confidence: 99%

“…This is considered an expedient approach, however, not only because of the practical limitations in the empirical V/H ratios to represent attenuation relations that may differ from the horizontal component, resulting in additional uncertainties, 22 but also the difficulty in applying it to site-specific ground motion procedures and soil-structure interaction analysis that are required for critical infrastructures. 23 To obtain site-specific ground motions, 1D SRA is typically performed in current practice. Following the 1D assumption, horizontal and vertical motions are assumed to be decoupled and are induced by vertically propagating shear and compressional waves, respectively.…”

mentioning

confidence: 99%

“…23,27 As a result, 1D vertical P wave propagation is considered unreliable and seldom used in current practice. 6,23,24,27 The performance of 1D vertical SRA becomes more perplexing considering that few successful applications of this approach for vertical response modelling are found in the literature, for example, the works by Johnson and Silva, 28 Fujii et al, 29 and Yang and Yan. 30 This indicates that the amplification mechanism for the vertical motion may be fundamentally different from that of vertically propagating compressional waves, and the prediction accuracy can be dependent on the subsurface condition and characteristics of the incoming wavefields consisting of both P and SV waves.…”

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confidence: 99%

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Applicability of 1D site response analysis to shallow sedimentary basins: A critical evaluation through physics‐based 3D ground motion simulations

Huang,

McCallen

2024

Earthq Engng Struct Dyn

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One‐dimensional site response analysis (1D SRA) remains the standard practice in considering the effect of local soil deposits and predicting site‐specific ground motions, although its range of applicability to realistic seismic wavefields is still in question. In this 1D approach, horizontal and vertical ground shaking are assumed to be induced by vertically propagating shear and compressional waves, respectively. A recent study based on analytical two‐dimensional (2D) plane waves and simple point source earthquake simulations has shown two mechanistic limitations in this 1D modelling technique for general inclined seismic waves, that is, systematic over‐prediction of the vertical motion and wave trapping in the 1D soil column. In this article, we evaluate in detail the applicability of this 1D modelling approach to realistic three‐dimensional (3D) simulated seismic wavefields in shallow sedimentary basins. Linear‐viscoelastic 1D SRA predictions using two types of input motions that are commonly used in practice—rock outcrop and in‐column motions, are compared with the reference true site response results from 3D earthquake simulations in terms of various measures in the frequency and time domain. It is shown that the horizontal motion in the 3D seismic wavefield exhibits dominant shear wave propagation phenomenon, while the vertical motion is a combined effect of compressional and shear waves and can be over‐predicted by the 1D approach when the incident seismic waves are inclined. Direct evidence of the wave refraction process that leads to the vertical motion over‐prediction is provided. 1D SRA with in‐column inputs can yield motions that have significantly longer duration compared to the true 3D site response solution due to trapped waves, casting in doubt the frequent need for increased soil damping in existing site studies to compensate for wave attenuation due to scattering alone. Sensitivity investigation on the increase of soil profile damping by a multiplier Dmul shows Dmul values compatible with those found in the literature for both horizontal and vertical motions. It is shown that the level of Dmul optimized for a best match of the spectral acceleration is dependent on the characteristic of the input motion and a larger Dmul is typically required for the vertical component. In contrast, 1D SRA with outcrop motions predicts motions with shorter significant duration due to its inability to capture the basin‐edge generated surface waves. A suite of ground motion simulations was performed to assess the sensitivity of the observations to the basin geologic structure including the velocity gradient, rock‐basin impedance contrast and basin depth. The analysis results show that the accuracy of the simplified 1D procedure is dependent on the wavefield composition of both the input motions and the true 3D site response solution. While the horizontal motions in shallow sedimentary basins can, to the first order, be reasonably captured by the simplified 1D approach, 1D SRA for the vertical component is in general not reliable and contributions from inclined shear waves should be accounted for in site‐specific evaluation of the vertical design ground motion.

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Seismic motion incoherency effects on SSSI responses of nuclear buildings

Wang,

Sun,

Liu

et al. 2024

Earthquake Engineering and Resilience

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The spatial variation of ground motion may significantly aggravate the seismic damage of large‐scale structures such as nuclear buildings. Establishing the seismic wave field with spatial features is the basis and key to seismic analysis of large‐scale complex structures. For the nuclear island buildings, which are arranged close to each other, the influence of structure–soil–structure interaction (SSSI) and incoherent motion on the structural seismic response should be considered. Taking a domestic nuclear power project as an example, the seismic response analyses under incoherent seismic motion and coherent seismic motion are carried out respectively. The seismic motion incoherency effects on the nuclear island buildings on the common raft and the adjacent seismic category I structure are explored by comparing the results of the in‐structure response spectrum (ISRS) at key elevations. The results indicate that the seismic motion incoherency does not change the trend of the response spectrum curve and the dominant frequency. Both the peak acceleration and zero‐period acceleration of ISRS are changed to some extent. Overall, seismic motion incoherency has a more significant impact on the ISRS of nuclear buildings with smaller volumes.

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Consistent site-response/soil-structure interaction analysis and evaluation

Cited by 7 publications

References 0 publications

Main Achievements of the Multidisciplinary SINAPS@ Research Project: Towards an Integrated Approach to Perform Seismic Safety Analysis of Nuclear Facilities

Main Achievements of the Multidisciplinary SINAPS@ Research Project: Towards an Integrated Approach to Perform Seismic Safety Analysis of Nuclear Facilities

Applicability of 1D site response analysis to shallow sedimentary basins: A critical evaluation through physics‐based 3D ground motion simulations

Seismic motion incoherency effects on SSSI responses of nuclear buildings

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