Centrifuge Modeling of Improved Design for Rocking Foundation Using Short Piles

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

doi:10.1061/(asce)gt.1943-5606.0002064

Cited by 15 publications

(7 citation statements)

References 29 publications

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“…Also included in the figure are the MAPE values of multivariate linear regression model (MLR) developed using the same input features and the same training and testing datasets. MLR is a linear, parametric model, where a hyperplane is used to model the relationship between the output and multiple input variables as expressed by Equation (10).…”

Section: Comparison Of Model Performances In Initial Training and Testing Phasesmentioning

confidence: 99%

“…Shallow foundations, with controlled rocking during earthquake loading, have been shown to have many beneficial effects on the seismic performance of structures by effectively acting as geotechnical seismic isolation mechanisms. More specifically, when the foundation is allowed to rock on its supporting soil, significant amount of seismic energy is dissipated due to plastic shearing and yielding of soil, and this in turn reduces the force and displacement demands transmitted to the superstructure [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Despite the mounting experimental evidences and rationales highlighting the benefits for inclusion of rocking foundations in seismic design [15][16][17][18][19], foundation rocking and soil yielding is still perceived as an unreliable geotechnical seismic isolation mechanism for reducing or eliminating seismic force and ductility demands on structures.…”

Section: Introductionmentioning

confidence: 99%

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Modeling of Seismic Energy Dissipation of Rocking Foundations Using Nonparametric Machine Learning Algorithms

Gajan

2021

Geotechnics

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The objective of this study is to develop data-driven predictive models for seismic energy dissipation of rocking shallow foundations during earthquake loading using multiple machine learning (ML) algorithms and experimental data from a rocking foundations database. Three nonlinear, nonparametric ML algorithms are considered: k-nearest neighbors regression (KNN), support vector regression (SVR) and decision tree regression (DTR). The input features to ML algorithms include critical contact area ratio, slenderness ratio and rocking coefficient of rocking system, and peak ground acceleration and Arias intensity of earthquake motion. A randomly split pair of training and testing datasets is used for initial evaluation of the models and hyperparameter tuning. Repeated k-fold cross validation technique is used to further evaluate the performance of ML models in terms of bias and variance using mean absolute percentage error. It is found that all three ML models perform better than multivariate linear regression model, and that both KNN and SVR models consistently outperform DTR model. On average, the accuracy of KNN model is about 16% higher than that of SVR model, while the variance of SVR model is about 27% smaller than that of KNN model, making them both excellent candidates for modeling the problem considered.

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Section: Comparison Of Model Performances In Initial Training and Testing Phasesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling of Seismic Energy Dissipation of Rocking Foundations Using Nonparametric Machine Learning Algorithms

Gajan

2021

Geotechnics

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“…Such undesirable deformations most probably won't jeopardize the structural safety, but can compromise the serviceability of the structure. Therefore, such soil improvement techniques as; shallow soil compaction, 22,28 a combination of shallow soil compaction and geogrid or geocell reinforcements, 23 unattached piles, [36][37][38] soil-cement grid, 39 and placement of concrete pads under the edges of the footing 40 ; have been proposed and investigated by researchers to control residual deformations engendered due to the foundation rocking.…”

Section: Introductionmentioning

confidence: 99%

Investigation of rocking mechanism of shallow foundations on sand via PIV technique

Moradi

Hosseini

Khezri

2023

Earthq Engng Struct Dyn

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Adoption of the rocking isolation concept in foundation design is considered as an effective method in reducing seismic loads of structures. Despite much research conducted on the rocking behavior of foundations, concerns regarding the practical application of the rocking foundation design concept still prevail. The concerns primary stem from the lack of accurate understanding and knowledge associated with the soil‐foundation deformation mechanisms during rocking motions. Determination of deformation mechanisms and soil mass failure modes during foundation rocking helps to gain insight into the rocking behavior, recognize influential factors on foundation settlement or uplift, and propose appropriate improvement strategies to control foundation deformations. The primary objective of this study is to investigate the deformation behavior and failure modes of the soil mass beneath a rocking foundation with various initial static vertical factors of safety (F.S.v) and embedment depths. To this end, a series of reduced‐scale slow‐cyclic tests under 1g condition have been conducted using a single degree of freedom (SDOF) model. To determine soil deformation mechanisms, soil displacement fields have been measured using Particle Image Velocimetry (PIV) technique. Soil deformation mechanisms during loading and unloading paths, as well as causes leading to the foundation settlement or uplift have been evaluated and discussed. Additionally, changes in the effective soil‐foundation contact area in different loading cycles have been examined based on the PIV results. Based on the results, soil deformation mechanisms in the loading portions include soil densification, wedge deformation and scoop deformation. As the footing embedment depth increases, wedge deformation mechanism becomes limited, while scoop deformation mechanism becomes stronger. Additionally, as the foundation F.S.v increases, the depth of influenced zone of the rocking foundation decreases and the soil displacement occurs to a more limited depth.

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“…Numerous ground improvement techniques for the rocking shallow foundation have been investigated, such as the integration of micropiles, 40 stone columns, 41 large rigid foundation slabs, 42,43 and unconnected piles—both short 44 and long 45,46 —to reduce or even eliminate the issues associated with soil settlements and permanent foundation rotations. Despite achieving this goal, the absence of energy dissipation—which would otherwise arise from the inelastic behavior of the bridge pier and the soil medium—results in larger inertial forces to the pier as well as larger deck displacements 47,48,14 .…”

Section: Introductionmentioning

confidence: 99%

Novel post‐tensioned rocking piles for enhancing the seismic resilience of bridges

El-Hawat

Fatahi

Taciroğlu

2021

Earthq Engng Struct Dyn

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The rocking pile foundation system is a relatively new design concept that can be implemented in bridges to improve their seismic performance. This type of foundation prevents plastic damage at the bridge piers and the foundation system, which are difficult to repair and can lead to collapse. However, lack of adequate energy dissipation in this type of foundation can result in large deck displacements and subsequent catastrophic failures of the bridge. The present study proposes a novel foundation system that integrates post-tensioned piles with the rocking foundation to simultaneously prevent plastic hinging at the piers and reduce the deck displacements during severe earthquakes. The effectiveness of the proposed foundation system is investigated and compared against the rocking pile and conventional fixed-base foundation systems using identical bridge configurations. Three-dimensional finite element models of these bridges were developed to capture possible nonlinear behavior of the bridge as well as soil-structure interaction effects. Six strong earthquakes with both horizontal components were selected and scaled to the appropriate seismic hazard level with a return period of 2475 years. Static pushover and nonlinear time-history analyses were then performed to compare the dynamic response of the bridges, including deck displacements, pier and pile inertial forces, and other nonlinear behavior experienced by the structure. The results reveal that by integrating the post-tensioned piles with the rocking foundation, the deck displacements were reduced to an acceptable limit without subjecting the bridge to any damage. In contrast, the bridge with the fixed base foundation experienced extensive damage at the piers, and the bridge with the rocking foundation experienced substantial deck displacements that ultimately led to unseating, resulting in the collapse of both bridges. It was therefore concluded that the proposed rocking foundation system with post-tensioned piles is the superior alternative and can be implemented in practice as an attractive solution due to the seismic protection it offers.

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Centrifuge Modeling of Improved Design for Rocking Foundation Using Short Piles

Cited by 15 publications

References 29 publications

Modeling of Seismic Energy Dissipation of Rocking Foundations Using Nonparametric Machine Learning Algorithms

Modeling of Seismic Energy Dissipation of Rocking Foundations Using Nonparametric Machine Learning Algorithms

Investigation of rocking mechanism of shallow foundations on sand via PIV technique

Novel post‐tensioned rocking piles for enhancing the seismic resilience of bridges

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