Analysis of Site Liquefaction Using Earthquake Records

Zeghal, Mourad; Elgamal, Ahmed

doi:10.1061/(asce)0733-9410(1994)120:6(996)

Cited by 258 publications

(117 citation statements)

References 6 publications

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“…According to Ghosh and Madabhushi [26], the liquefaction zone is associated with lower shear wave velocity and thus the generation of excess pore water pressure in this region will drop the natural frequency of the soil profile. This phenomena have been also observed in the field and reported by several authors [27][28][29][30].…”

Section: Ground Response Analysissupporting

confidence: 80%

Numerical simulation of liquefaction effects on seismic SSI

López-Caballero¹,

Farahmand-Razavi²

2008

Soil Dynamics and Earthquake Engineering

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The present paper deals with the influence of soil non-linearity, introduced by soil liquefaction, on the soil-foundation-structure interaction phenomena. The objective is to reveal the beneficial or unfavourable effects of the non-linear SSI on both structural drift and settlement of a given structure. Factors such as the signal modification due to liquefaction, and ratios of fundamental frequencies of soil, structure and signal may play an important role on the damage of the structure. The importance of each of these factors is evaluated through a significant parametric study. A 2D coupled finite element modelling is carried out using an elastoplastic multimechanism model to represent the soil behaviour. This paper presents the research work we did in the framework of the European Community project NEMISREF (New methods of mitigation of seismic risk on existing foundations, GRDI-40457), to study possible retrofitting measures using GEFDYN computational tools.

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Section: Ground Response Analysissupporting

confidence: 80%

Numerical simulation of liquefaction effects on seismic SSI

López-Caballero¹,

Farahmand-Razavi²

2008

Soil Dynamics and Earthquake Engineering

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“…The time-dependence of shear stresses and shear strains was evaluated at selected depths within clay layers from the corrected data using the procedure of Zeghal and Elgamal (1994).…”

Section: Derivation Of Shear Stresses and Strainsmentioning

confidence: 99%

“…Referring to the schematic stress-strain loop in Fig. 10, we apply the approach of Zeghal and Elgamal (1994) to compute secant shear modulus, G sec , and damping, D. Stress-strain loops like those shown in Fig. 9 were generated for each ground motion imposed on the models, and G sec and D were computed.…”

Section: Modulus Reduction and Damping Behaviormentioning

confidence: 99%

Centrifuge Modeling Studies of Site Response in Soft Clay over Wide Strain Range

Afacan

Brandenberg

Stewart

2014

J. Geotech. Geoenviron. Eng.

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Centrifuge modeling studies of site response in soft clay over wide strain range Abstract: Centrifuge models of soft clay deposits were shaken with suites of earthquake ground motions to study site response over a wide strain range. The models were constructed in an innovative hinged-plate container to effectively reproduce one dimensional ground response boundary conditions. Dense sensor arrays facilitate back-calculation of modulus reduction and damping values that show modest misfits from empirical models. Low amplitude base motions produced nearly elastic response in which ground motions were amplified through the soil column and the fundamental site period was approximately 1.0s. High intensity base motions produced shear strains higher than 10%, mobilizing shear failure in clay at stresses larger than the undrained monotonic shear strength. We attribute these high mobilized stresses to rate effects, which should be considered in strength parameter selection for nonlinear analysis. This nonlinear response de-amplified short period spectral accelerations and lengthened the site period to 3.0s. The nonlinearity in spectral amplification is parameterized in a form used for site terms in ground motion prediction equations to provide empirical constraint unavailable from ground motion databases.

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“…The corresponding second-order shear strains at levels z i and (z i-1 + z i )/2 are (Elgamal et al 1995) where u i (t) = u (z i ,t) is the absolute displacement evaluated by integrating the recorded acceleration history, ü (z i ,t), twice. These estimates of the stress and strain estimates are accurate to second order (Zeghal et al 1994). To process the measured acceleration data, a filter was employed to eliminate high-frequency noise and baseline drifts from the estimates of the displacement.…”

Section: Identification Procedures For Shear Stress and Shear Strainmentioning

confidence: 99%

“…Soil liquefaction has been documented in soil deposits by measuring the time histories of the acceleration and the pore pressure in vertical downhole seismic arrays and analyzed using system identification techniques that identified the stress-strain responses of liquefiable soils (e.g., Abdel-Ghaffar et al 1979, Zeghal et al 1994, Zeghal et al 2009, Oskay et al 2011, Lozano-Galant et al 2013). However, a recent review of geotechnical system identification methods (Oskay et al 2011) indicates that system identification has not yet been applied to the responses of liquefiable soils around the pile foundations of tall buildings, which is an important problem in earthquake engineering practice that remains poorly documented by experimental data.…”

Section: Introductionmentioning

confidence: 99%

Responses of Liquefiable Soils in Pile Group Foundations of Tall Buildings from Shaking Table Tests

Yang

2016

Journal of Asian Architecture and Building Engineering

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The responses of liquefiable soils around pile group foundations of tall buildings to earthquakes were measured using acceleration arrays in shaking table tests. System identification techniques were used to analyze the measured accelerations and pore pressures and to calculate the shear stress and shear strain in the soil inside and outside the pile group of a 12-story building as well as the soil shear moduli and damping. The analysis shows that the calculated soil stiffness is similar to the stiffness determined using laboratory tests and that the soil damping is higher. It also shows that pore pressure buildup reduces the shear wave velocity and the soil stiffness.

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Analysis of Site Liquefaction Using Earthquake Records

Cited by 258 publications

References 6 publications

Numerical simulation of liquefaction effects on seismic SSI

Numerical simulation of liquefaction effects on seismic SSI

Centrifuge Modeling Studies of Site Response in Soft Clay over Wide Strain Range

Responses of Liquefiable Soils in Pile Group Foundations of Tall Buildings from Shaking Table Tests

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