Design Considerations for Rocking Foundations on Unattached Piles

Allmond, Jacquelyn; Kutter, Bruce L.

doi:10.1061/(asce)gt.1943-5606.0001162

Cited by 31 publications

(8 citation statements)

References 13 publications

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“…Finally, the yielding of the moment occurred at a very small rotation angle of about 0.002 rad. This phenomenon is similar with a shallow foundation behaviour on a relatively rigid base with a high safety factor (Allmond and Kutter 2014). Therefore, the results indicate that unconnected piles with an interposed layer are optimization options that increase hysteresis damping and limit structural mobilized moments.…”

Section: Moment and Rotation Relationship From Stage Testssupporting

confidence: 71%

“…The shape of the moment-rotation loop was slightly different between the shallow foundation and the unconnected pile foundation with an interposed layer. Gajan and Kutter (2008) and Allmond and Kutter (2014) noted that the hysteresis curve of the rocking behaviour varies depending on the factor of safety with respect to bearing capacity considering the static vertical loads, FS V . For the model tests reported here, the FS V for the shallow foundation resting on dense sand was estimated to be between about 60 and 90.…”

Section: Moment-rotation During the Early Strong Earthquakesmentioning

confidence: 99%

“…Previous studies on unconnected pile foundations focused primarily on static bearing capacity and system settlement for different pile-to-pile cap connections (Fioravante and Giretti 2010;Eslami et al 2012). Experimental and numerical analyses on the seismic behaviour of unconnected pile foundations have also been performed (Teguh et al 2006;Allmond and Kutter 2014;Antonellis and Panagiotou 2014;Park et al 2017). Antonellis and Panagiotou (2014) conducted a three-dimensional numerical analysis on the pile foundation, shallow foundation and rocking pile foundation, indicating that the pier on the rocking pile foundation experienced much less structural damage than the conventionally designed bridge.…”

Section: Introductionmentioning

confidence: 99%

“…Antonellis and Panagiotou (2014) conducted a three-dimensional numerical analysis on the pile foundation, shallow foundation and rocking pile foundation, indicating that the pier on the rocking pile foundation experienced much less structural damage than the conventionally designed bridge. Allmond and Kutter (2014) investigated the seismic behaviour of unattached pile foundations in liquefiable sand by dynamic centrifuge tests and showed that the rocking behaviour depends on the pile arrangements. Previous studies have examined the behaviours of unconnected pile foundations compared to conventional shallow foundations and connected pile foundations.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Moment and Rotation Relationship From Stage Testssupporting

confidence: 71%

Section: Moment-rotation During the Early Strong Earthquakesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Jo³

et al. 2018

Bull Earthquake Eng

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“…Kim et al [10] evaluated the seismic behaviour of superstructure due to the rocking motion of a foundation within a centrifuge. Allmond and Kutter [11] considered rocking foundations on unattached piles. Liu et al [12] presented a centrifuge test program that incorporated inelastic behaviour into model building systems via yielding of both structural and foundation components.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the dynamic behaviour of a storage tank with different foundation types focusing on the soil‐foundation‐structure interactions using centrifuge model tests

Park

Kwon

et al. 2017

Earthq Engng Struct Dyn

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Summary This paper proposes a dynamic centrifuge model test method for the accurate simulation of the behaviours of a liquid storage tank with different types of foundations during earthquakes. The method can be used to determine the actual stress conditions of a prototype storage‐tank structure. It was used in the present study to investigate the soil‐foundation‐structure interactions of a simplified storage tank under two different earthquake motions, which were simulated using a shaking table installed in a centrifuge basket. Three different types of foundations were considered, namely, a shallow foundation, a slab on the surface of the ground connected to piles and a slab with disconnected piles. The test results were organised to compare the ground surface and foundation motions, the slab of foundation and top of structure motions and the horizontal and vertical motions of the slab, respectively. These were used to establish the complex dynamic behaviours of tank models with different foundations. The effects of soil–foundation–structure interaction with three foundation conditions and two different earthquake motions are focused and some important factors, that should be considered for future designs are also discussed in this research. Copyright © 2017 John Wiley & Sons, Ltd.

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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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Design Considerations for Rocking Foundations on Unattached Piles

Cited by 31 publications

References 13 publications

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

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

Investigation of the dynamic behaviour of a storage tank with different foundation types focusing on the soil‐foundation‐structure interactions using centrifuge model tests

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

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