Comparison between cyclic and dynamic rocking behavior for embedded shallow foundation using centrifuge tests

Ko, Kil‐Wan; Ha, Jeong‐Gon; Park, Heon-Joon; Kim, Dong-Soo

doi:10.1007/s10518-018-0409-6

Cited by 22 publications

(4 citation statements)

References 45 publications

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“…They concluded that the performance of the soil-foundation system, subjected to slow cyclic loading, can be used to anticipate its performance under dynamic loading. This similarity in response, however, can be expected only for rigid structures [50].…”

Section: Loading Protocolmentioning

confidence: 87%

Effect of Footing Shape on the Rocking Behavior of Shallow Foundations

Khezri,

Moradi,

Mir Mohammad Hosseini

et al. 2024

Buildings

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Sources such as wind or severe seismic activity often exert extreme lateral loading onto the shallow foundations supporting high-rise structures such as bridge piers, buildings, shear walls, and wind turbine towers. Such loading conditions may cause the foundation to exhibit nonlinear responses such as uplift and bearing capacity mobilization of the supporting soil (i.e., rocking behavior). Previous numerical and experimental studies suggest that while such inelastic behaviors may engender residual deformations in the soil–foundation system, they offer potential benefits to the overall integrity of structures through dissipating energy and reducing inertia forces transmitted to the superstructure, thereby limiting seismic demand on structural elements. This study investigates the effect of footing shape on the rocking performance of shallow foundations in different subgrade densities and initial vertical factor of safety (FSv). To this end, a series of reduced-scale slow cyclic tests under 1 g condition were conducted using a single degree of freedom (SDOF) structure model. The performance of different footing shapes was studied in terms of moment capacity, recentering ratio, rocking stiffness, damping ratio, and settlement. For three foundations with different length-to-width ratios, the results indicate that increasing the safety factor and length-to-width ratio leads to thinner, S-shaped moment–rotation curves, mainly owing to the enhanced recentering capability and the P-δ effect. Moreover, across all foundation types, the repetition of a limited loading cycles with consistent rotation amplitude does not cause stiffness degradation or moment capacity reduction.

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Section: Loading Protocolmentioning

confidence: 87%

Effect of Footing Shape on the Rocking Behavior of Shallow Foundations

Khezri,

Moradi,

Mir Mohammad Hosseini

et al. 2024

Buildings

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“…To obtain detailed structural responses, the equation of motion (EOM) of the soil-structure system that considers the aforementioned three degree-of-freedom (3DOF) is expressed by Equation (1) [8,9,20].…”

Section: Soil-structure Interaction (Ssi) Parameters and Optimum Ssi Parameter Selection Proceduresmentioning

confidence: 99%

“…To estimate an accurate structural response for seismic design, the soil-structure interaction (SSI) effect has been considered as the crucial effect for the seismic evaluation of the structure. There have been various studies on the soil-structure interaction (SSI) effect but the subject of each study was not comprehensive but limited to specific parameters or phenomena (e.g., spring constant and damping coefficient [1][2][3][4][5][6], effective profile depth [7], and rocking behavior [8][9][10][11]). With regard to the SSI analysis, four procedures were introduced in FEMA356 [12]: Linear static procedure (LSP), linear dynamic procedure (LDP), nonlinear static procedure (NSP), and nonlinear dynamic procedure (NDP).…”

Section: Introductionmentioning

confidence: 99%

Optimization of Two Soil–Structure Interaction Parameters Using Dynamic Centrifuge Tests and an Analytical Approach

Kim

et al. 2020

Sustainability

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The response of the structure subjected to an earthquake load is greatly affected by the properties of the structure and soil so it is very important to accurately determine the characteristics of the structure and soil for analysis. However, studies on the effective profile depth where soil properties are determined, have been conducted in the presence of restricted conditions (i.e., surface foundation, linear soil properties), and without any considerations on damping. In case of the effective height of structure that affects its rocking behavior, it was only theoretically or empirically determined. In addition, most previously published studies on soil–structure interaction (SSI) focused on limited effects and parameters (e.g., rocking behavior, embedment effect, effective profile depth, spring constant, and damping coefficient) and not on comprehensive SSI parameters. Furthermore, no detailed validation procedure has been set in place which made it difficult to validate the SSI parameters. Since the effective height of structure and effective profile depth are the basis of all the input parameters of SSI analysis, it is important to validate and determine them. Therefore, in this study, the procedure used to optimize the two SSI parameters was established based on an analytical approach that considered all the possible SSI parameters that were investigated from conventional codes and studies and physical model tests. As a result of this study, the optimum values of the effective height of the structure and effective profile depth were respectively determined according to (a) the height from the bottom part of the foundation to the center of the mass of the superstructure, and according to (b) the depth at values equal to four times the radius of the foundation.

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“…The mobilized moments were calculated by multiplying the effective stiffness, the structural net displacement and the system height as Eq. 3 (Kim et al 2015;Ko et al 2018). The system height for the moment derivation is 174 mm in model scale, the distance from the centre of the foundation to the lumped mass where M m rotational moment of the system, k θ rocking stiffness of the foundation, u the rotation angle of the foundation, m s , k s the effective mass and stiffness of the structure, h = the height of the system.…”

Section: Moment-rotation During the Early Strong Earthquakesmentioning

confidence: 99%

Investigation of seismic performances of unconnected pile foundations using dynamic centrifuge tests

Jo³

et al. 2018

Bull Earthquake Eng

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An unconnected pile foundation allows separation between the lower pile and the pile cap, and it has been proposed as an effective foundation type for reducing the seismic load during strong earthquakes. However, previous quantitative evaluations of unconnected piles with various foundation types and earthquake intensities are inadequate. In this study, the influence of base shaking level and the material of the interposed layer between pile and pile cap on the seismic behaviour of unconnected piles were evaluated using a centrifuge model test to reproduce the field stress conditions. A dynamic centrifuge model test was completed on an experimental model consisting of dry sandy soil, a foundation and a single degreeof-freedom structure. The acceleration of the structure and the settlement of the foundation system were measured during base shaking. For the unconnected pile system, the structural seismic load reduction effect due to rocking behaviour was confirmed, and the unconnected pile foundation with the interposed layer with large stiffness had less vertical settlement than the conventional shallow foundation. Finally, the rotational stiffness and damping ratio for the foundation system used in the centrifuge model tests were derived and discussed.

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Comparison between cyclic and dynamic rocking behavior for embedded shallow foundation using centrifuge tests

Cited by 22 publications

References 45 publications

Effect of Footing Shape on the Rocking Behavior of Shallow Foundations

Effect of Footing Shape on the Rocking Behavior of Shallow Foundations

Optimization of Two Soil–Structure Interaction Parameters Using Dynamic Centrifuge Tests and an Analytical Approach

Investigation of seismic performances of unconnected pile foundations using dynamic centrifuge tests

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