Assessment of damping models in FLAC

Mánica, Miguel A.; Ovando, E.; Botero, Eduardo Uribe

doi:10.1016/j.compgeo.2014.02.007

Cited by 38 publications

(24 citation statements)

References 10 publications

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“…A non-viscous damping formulation was used for the structural elements, called local damping in FLAC3D terminology, which operates by adding or subtracting mass from a structural node at certain times during a cycle of oscillation, thus resulting in a frequency-independent energy dissipation [19,30,31]. The adopted damping ratio was D = 5 %.…”

Section: The Structurementioning

confidence: 99%

Assessment of dynamic soil-structure interaction effects for tall buildings: A 3D numerical approach

Scarfone

Morigi

Conti

2020

Soil Dynamics and Earthquake Engineering

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Soil-structure interaction (SSI) phenomena are typically studied in the frequency-domain using the substructure approach, involving several simplifications. In this study, SSI effects for a 20-storey building are studied numerically performing time-domain 3D non-linear dynamic analyses, using an elastoplastic nonlinear constitutive model for the soil. Three foundation systems-a relatively shallow, a deeply embedded and a pile foundation-and two soil profiles are investigated and compared. Specifically, relative merits of site amplification, kinematic interaction and inertial interaction are isolated, and the role of foundation deformability and local stratigraphy is highlighted. To isolate such features, the results of the complete 3D models are compared with those provided by 3D numerical analyses of the sole building, of the foundation-soil systems and of the free-field soil deposit. Numerical results show that, for tall buildings, an increase in foundation deformability leads to a decrease of the maximum base shear force (seismic demand), to a higher rigid rotation of the foundation, but not to appreciably higher displacements of the structure. Moreover, possible situations where a (decoupled) substructure approach can lead to a misinterpretation of SSI phenomena are highlighted, as in the case of deep foundations crossing very soft soil layers. In addition, the use of embedded pile elements was proven to be an effective strategy in reducing the computational cost when performing complex 3D simulations of dynamic SSI problems.

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Section: The Structurementioning

confidence: 99%

Assessment of dynamic soil-structure interaction effects for tall buildings: A 3D numerical approach

Scarfone

Morigi

Conti

2020

Soil Dynamics and Earthquake Engineering

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“…The energy dissipation primarily occurs due to frequency-independent hysteretic behaviour of soil, which can be incorporated in dynamic FE analysis using a nonlinear stress-strain relationship (Kwok et al 2007;Mánica et al 2014;Tsai et al 2014). As an elasto-plastic soil D r a f t model is used in the present study, the plastic flow can simulate hysteretic damping when loading/unloading occurs from yield strength and therefore additional damping is required only in the elastic part (Zhai et al 2004;Mánica et al 2014). For cyclic loading inside the yield surface, energy dissipation can be achieved by nonlinear variation of stiffness with Masing's rule (Masing 1926 In Abaqus, the mass proportional damping is neglected in Eulerian materials.…”

Section: Materials Dampingmentioning

confidence: 99%

Large-deformation finite-element modelling of earthquake-induced landslides considering strain-softening behaviour of sensitive clay

et al. 2019

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Large-scale landslides in sensitive clays cannot be explained properly using the traditional limit equilibrium or Lagrangian-based finite-element (FE) methods. In the present study, dynamic FE analysis of sensitive clay slope failures triggered by an earthquake is performed using a large-deformation FE modelling technique. A model for post-peak degradation of undrained shear strength as a function of accumulated plastic shear strain (strain-softening) is implemented in FE analysis. The progressive development of “shear bands” (the zone of high plastic shear strains) that causes the failure of a number of soil blocks is simulated successfully. Failure of a slope could occur during an earthquake and also at the post-quake stage until the failed soil masses come to a new static equilibrium. Upslope retrogression and downslope runout of the failed soil blocks are examined for varying geometries and soil properties. The present FE simulations can explain some of the conditions required for different types of seismic slope failure (e.g., spread, flowslide or monolithic slides) to be triggered, as observed in the field.

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“…Earthquake ground-motions are recorded in three orthogonal components: two horizontal (normally N-S and E-W) and one vertical. These as-recorded time histories are usually employed to derive input motions for dynamic analyses [1][2][3]. However, the intensity of ground motions is not uniform in all directions.…”

Section: Introductionmentioning

confidence: 99%