Numerical Investigation of V
            <sub>s</sub>
            Spatial Variability Effects on the Seismic Response Estimated Using 2D and 1D Site Response Analyses

Pretell, Renmin; Ziotopoulou, Katerina; Abrahamson, Norman A.

doi:10.1061/9780784484043.020

Cited by 3 publications

(4 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Herein, attention is placed on the consistency of the improved performance of the 84 th percentile over the median 1D SRA-based AFs, at the fundamental frequency ( f / f 0 = 1). A study of the effects of the site conditions on the 2D SRA-based TFs and AFs and the sampled 1D SRA-based TFs and AFs is presented by Pretell et al (2022).…”

Section: Parametric Evaluationmentioning

confidence: 99%

Conducting 1D site response analyses to capture 2D V_S spatial variability effects

2022

Self Cite

View full text Add to dashboard Cite

One-dimensional site response analyses (1D SRAs) with shear-wave velocity ( VS) randomization are commonly performed to estimate median site-specific amplification factors (AFs) under the implicit assumption that this approach yields a realistic response. In this work, an investigation is conducted to determine the appropriate amount of VS randomization (σlnVs) needed to capture a median response that accounts for 2D VS spatial variability effects. Results from 2D SRAs and 1D SRAs with VS randomization show that the median 2D seismic responses are generally higher than 1D responses at the site’s fundamental frequency, and that higher VS variability has a mild impact on the median 2D seismic response amplitude at the fundamental frequency, whereas it significantly reduces the median 1D response. Findings indicate that the 84th percentile AFs based on 1D SRAs conducted with VS randomization using σlnVs = 0.25, approximate well with the more realistic median 2D SRA-based AFs around the fundamental frequency, while the 70th to 60th percentiles might be more appropriate at higher frequencies. The benefit of using percentiles of the 1D SRA-based AFs higher than the median is shown for different site conditions and supported by comparisons against empirical data from four downhole sites.

show abstract

Section: Parametric Evaluationmentioning

confidence: 99%

Conducting 1D site response analyses to capture 2D V_S spatial variability effects

2022

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Approach For Improving Site Response Predictionsmentioning

confidence: 99%

“…However, the assumptions of the 1D SRA approach are unrealistic and thus 1D SRAs cannot predict site response accurately even for 1D-like sites, or cases with V S profiles exempt from measurement errors, as demonstrated in numerical investigations (e.g. de la Torre et al, 2021; Pretell et al, 2022b). Such errors are herein referred to as “intrinsic errors.” Two major sources of such errors are (1) the unrealistic wave reverberations and spurious resonances that lead to overpredictions of the amplitudes at the sites’ fundamental frequency (Boore, 2013) and (2) the inability to simulate energy dissipation mechanisms, thus leading to an overall overprediction of site response amplitudes.…”

Section: Proposed Approach For Conducting 1d Site Response Analysesmentioning

confidence: 99%

A borehole array data–based approach for conducting 1D site response analyses I: Damping and V_S randomization

2023

Self Cite

View full text Add to dashboard Cite

One-dimensional site response analysis (1D SRA) remains the state of practice to estimate site-specific seismic response, despite the ample evidence of discrepancies between observations and 1D SRA-based predictions. These discrepancies are due to errors in the input parameters, intrinsic limitations in the predicting capabilities of 1D SRAs even for sites relatively compliant with the 1D SRA assumptions, and the inability of 1D SRAs to model three-dimensional (3D) wave propagation phenomena. This article aims at reducing 1D SRA mispredictions using small-strain damping profiles factored by a damping multiplier ( Dmul) and randomized shear-wave velocity ( VS) profiles. An approach for conducting 1D SRAs for site-specific site response assessment is developed to reduce the 1D SRA errors in magnitude and variability. First, sites from a database of 534 downhole sites are classified as 1D- or 3D-like, depending on the substructure conditions inferred from observed transfer functions. Second, data from the 1D-like sites are compared against predictions from 1D SRAs conducted using various trials of Dmul and VS standard deviations [Formula: see text] for VS randomization. Third, Dmul and [Formula: see text] are selected based on their combined ability to reduce the root mean square error (RMSE) in SRA predictions. Results indicate that 1D SRAs conducted with Dmul = 3 and [Formula: see text] lead to an overall minimum RMSE and thus provide more accurate site response estimates. The use of these parameters in forward SRA predictions is discussed in a companion paper.

show abstract

“…Despite the aforementioned advantages, 1D SRA also has some obvious drawbacks. Various studies and observations have demonstrated that 1D SRA cannot accurately capture (1) the soil profile and ground motion spatial variability (Madiai et al, 2016; Makra and Chávez-García, 2016; Pretell et al, 2022) and basin effects (McGann et al, 2021); (2) topographic site-effect amplification/de-amplification (Bahrampouri and Rodriguez-Marek, 2023; Smerzini et al, 2011); and (3) impact of incident angles of seismic waves and wave scattering (de la Torre et al, 2022; Oral et al, 2022). Formulations and mechanisms of 1D SRA have inevitably limited its capability to consider these factors.…”

Section: Introductionmentioning

confidence: 99%

A comparison of ground motions predicted through one-dimensional site response analyses and three-dimensional wave propagation simulations at regional scales

Zhang,

Dong,

Crempien

et al. 2024

Earthquake Spectra

View full text Add to dashboard Cite

One-dimensional (1D) site response analysis (SRA), which considers vertically propagating seismic waves from the bedrock to the surface, has been a common technique among geotechnical engineers to examine site-specific ground shaking. However, observations from past earthquakes and analytical studies indicate that idealizations ingrained in 1D SRA may be too severe to capture the ground truth, such as the omissions of spatial variability of soil properties, surface topography, and basin and directivity effects. Physics-based three-dimensional ground motion simulations (GMSs) can incorporate these factors and yield more reliable predictions. In this study, we utilize ground motions from 57 physics-based broadband (from 0 to 8–12 Hz) GMS for a region of Istanbul. A total of 2912 sites with experimentally measured soil profiles that are distributed over the 30 km-by-12.5 km area are also modeled as soil columns and analyzed through 1D SRA. The ground responses from 1D SRA and three-dimensional (3D) GMS are then compared for all 57 earthquake scenarios. These systematic comparisons are then used for examining model features that are correlated with variations in the ratios of various ground motion intensity measures (IMs) and for developing regression-based formulas that can be used for determining simple factors for the considered region to correctly scale (up or down) the site-specific ground motion intensities obtained from 1D SRA, including peak ground acceleration (PGA), peak ground velocity (PGV), and spectral acceleration ( Sa) values.

show abstract

Numerical Investigation of V _s Spatial Variability Effects on the Seismic Response Estimated Using 2D and 1D Site Response Analyses

Cited by 3 publications

References 13 publications

Conducting 1D site response analyses to capture 2D V_S spatial variability effects

Conducting 1D site response analyses to capture 2D V_S spatial variability effects

A borehole array data–based approach for conducting 1D site response analyses I: Damping and V_S randomization

A comparison of ground motions predicted through one-dimensional site response analyses and three-dimensional wave propagation simulations at regional scales

Contact Info

Product

Resources

About

Numerical Investigation of V s Spatial Variability Effects on the Seismic Response Estimated Using 2D and 1D Site Response Analyses

Cited by 3 publications

References 13 publications

Conducting 1D site response analyses to capture 2D VS spatial variability effects

Conducting 1D site response analyses to capture 2D VS spatial variability effects

A borehole array data–based approach for conducting 1D site response analyses I: Damping and VS randomization

A comparison of ground motions predicted through one-dimensional site response analyses and three-dimensional wave propagation simulations at regional scales

Contact Info

Product

Resources

About

Numerical Investigation of V _s Spatial Variability Effects on the Seismic Response Estimated Using 2D and 1D Site Response Analyses

Conducting 1D site response analyses to capture 2D V_S spatial variability effects

Conducting 1D site response analyses to capture 2D V_S spatial variability effects

A borehole array data–based approach for conducting 1D site response analyses I: Damping and V_S randomization