The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Xia Xiushe - One of the best experts on this subject based on the ideXlab platform.
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Restrainer Effect on Rocking Response of Tall Pier with Pile Foundations
Journal of Tongji University, 2020Co-Authors: Xia XiusheAbstract:Modeling method of the restrainers was proposed for the seismic analysis of the tall pier-Pile Foundations rocking isolated system.Effect of the restrainer on the rocking response of a railway tall pier was investigated through nonlinear time history analysis by inputting three strong ground motions.The displacement at the top and the moment at the bottom of the pier are discussed as functions of the initial gap and yielding force of the restrainer.The results show that the restrainer decreases the displacement at pier top,while it increases the base moment.The initial gap of restrainer has greater effect on the top displacement than the base moment.It is also observed that the yield force of restrainer affects the rocking response of the tall pier-Pile Foundations isolated system significantly.
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Effect of near-field ground motion on the rocking response of tall pier with Pile Foundations
Journal of the Harbin Institute of Technology, 2020Co-Authors: Xia XiusheAbstract:To determine the scope of self-centering for the tall pier with Pile Foundations,the effect of nearfield ground motion on rocking response was investigated. Fault distance was used as parameters identifying near-field to select ground motion. Two springs simulated the uplift and rocking of the pier. Rocking response of a railway tall pier was investigated through nonlinear time history analysis by inputting strong ground motions. The results show that the displacement at pier top is significantly increased by near-field horizontal ground motion. It is also observed that vertical ground motion is unfavorable to the rocking response of tall pier with Pile Foundations. Rocking devices for tall piers in near-fault zones should be cautious.
Panagiotis Kotronis - One of the best experts on this subject based on the ideXlab platform.
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Study on the stiffness degradation and damping of Pile Foundations under dynamic loadings
Engineering Structures, 2020Co-Authors: Zheng Li, Sandra Escoffier, Panagiotis KotronisAbstract:Abstract This paper presents a comprehensive study on the different behaviour of batter and vertical Pile Foundations in terms of stiffness degradation and damping properties under dynamic loadings. Firstly, dynamic centrifuge tests were carried out and the variations of translational/rotational stiffness and the associated damping properties were identified from a series of hysteretic loops. Results show that for the rocking behaviour, the presence of batter Piles causes a small decrease of the rotational stiffness and a great increase of the rotational damping; for the horizontal translation behaviour, batter Pile foundation has much higher horizontal stiffness and translational damping compared to the vertical foundation. Then, a set of stiffness degradation and damping curves for the translational and rotational behaviour of batter and vertical Pile Foundations are proposed. Finally, the proposed stiffness degradation and damping curves were validated numerically by using equivalent linear approach. The numerical validation shows a good agreement with the experimental results.
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centrifuge modeling of batter Pile Foundations under earthquake excitation
Soil Dynamics and Earthquake Engineering, 2016Co-Authors: Zheng Li, Sandra Escoffier, Panagiotis KotronisAbstract:Abstract Although batter Pile Foundations are widely used in civil engineering structures, their behavior under seismic loadings is not yet thoroughly understood. This paper provides insights about the differences in the behavior of batter and vertical Piles under seismic soil-Pile-superstructure interaction. An experimental dynamic centrifuge program is presented, where the influences of the base shaking signal and the height of the gravity center of the superstructure are investigated. Various seismic responses are analyzed (displacement and rotation of the Pile cap, total shear force at the Pile cap level, overturning moment, residual bending moment, total bending moment and axial forces in Piles). It is found that in certain cases batter Piles play a beneficial role on the seismic behavior of the Pile foundation system. The performance of batter Piles depends not only on the characteristics of the earthquakes (frequency content and amplitude) but also on the type of superstructures they support. This novel experimental work provides a new experimental database to better understand the behavior of batter Pile Foundations in seismic regions.
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Centrifuge modeling of batter Pile Foundations under sinusoidal dynamic excitation
Bulletin of Earthquake Engineering, 2016Co-Authors: Zheng Li, Sandra Escoffier, Panagiotis KotronisAbstract:Batter Pile (or inclined Pile) Foundations are widely used in civil engineering structures. However, their behavior under dynamic loadings is not yet thoroughly understood. This paper presents an experimental work on the behavior of batter and vertical Piles considering dynamic soil-Pile-superstructure interactions. A series of dynamic centrifuge tests were performed using sinusoidal excitations. The influence of the base shaking (frequency content and amplitude) and of the height of the center of gravity of the superstructure is investigated. Seismic responses are analyzed considering the Pile cap displacements and forces (total base shear, overturning and residual moments, axial forces). It is found that in certain cases batter Piles play a beneficial role on the dynamic behavior of the Pile foundation system. This novel experimental work provides an important database on the behavior of batter Pile Foundations under dynamic loadings.
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Centrifuge modelling of inclined Pile Foundations under seismic actions
2014Co-Authors: Zheng Li, Sandra Escoffier, Panagiotis KotronisAbstract:Although inclined Pile Foundations are sometimes used in civil engineering structures, their behavior under seismic loadings is not yet thoroughly understood. This paper presents an experimental work on inclined Pile Foundations under earthquake loadings. Dynamic centrifuge tests are performed to investigate the influence of inclined Piles on the superstructures and to quantify the soil-structure interaction. Some key parameters are analyzed such as the residual bending moment, the total bending moment and the axial forces. It is found that in certain cases inclination plays a beneficial role to the seismic behavior of the Pile foundation system and that the presence of inclined Piles increases its natural frequency. Comparing to a vertical Pile foundation, the residual bending moment envelope curve is different and larger values are observed. This novel experimental work provides significant data to understand the behavior of inclined Pile Foundations in seismic regions.
Francesco Basile - One of the best experts on this subject based on the ideXlab platform.
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effects of tunnelling on Pile Foundations
Soils and Foundations, 2014Co-Authors: Francesco BasileAbstract:Abstract An efficient analysis method is presented for estimating the effects induced by tunnelling on existing Pile Foundations. The method is based on a two-stage procedure: (1) an estimate of the free-field ground movements caused by the tunnel excavation, and (2) an analysis of the Pile group subjected to the computed free-field ground movements. The first step may be carried out using alternative approaches, ranging from empirical methods to 3D numerical analyses. The second step is performed by PGROUPN, a computer program for Pile-group analysis based on a non-linear boundary element solution. The validity of the approach is assessed by comparing it with alternative numerical solutions and field measurements. The results indicate that the method is capable of generating reasonable predictions of Pile response for many cases of practical interest, thus offering substantial cost savings over a complete 3D analysis of tunnel–soil–Pile interaction.
Zheng Li - One of the best experts on this subject based on the ideXlab platform.
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Study on the stiffness degradation and damping of Pile Foundations under dynamic loadings
Engineering Structures, 2020Co-Authors: Zheng Li, Sandra Escoffier, Panagiotis KotronisAbstract:Abstract This paper presents a comprehensive study on the different behaviour of batter and vertical Pile Foundations in terms of stiffness degradation and damping properties under dynamic loadings. Firstly, dynamic centrifuge tests were carried out and the variations of translational/rotational stiffness and the associated damping properties were identified from a series of hysteretic loops. Results show that for the rocking behaviour, the presence of batter Piles causes a small decrease of the rotational stiffness and a great increase of the rotational damping; for the horizontal translation behaviour, batter Pile foundation has much higher horizontal stiffness and translational damping compared to the vertical foundation. Then, a set of stiffness degradation and damping curves for the translational and rotational behaviour of batter and vertical Pile Foundations are proposed. Finally, the proposed stiffness degradation and damping curves were validated numerically by using equivalent linear approach. The numerical validation shows a good agreement with the experimental results.
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centrifuge modeling of batter Pile Foundations under earthquake excitation
Soil Dynamics and Earthquake Engineering, 2016Co-Authors: Zheng Li, Sandra Escoffier, Panagiotis KotronisAbstract:Abstract Although batter Pile Foundations are widely used in civil engineering structures, their behavior under seismic loadings is not yet thoroughly understood. This paper provides insights about the differences in the behavior of batter and vertical Piles under seismic soil-Pile-superstructure interaction. An experimental dynamic centrifuge program is presented, where the influences of the base shaking signal and the height of the gravity center of the superstructure are investigated. Various seismic responses are analyzed (displacement and rotation of the Pile cap, total shear force at the Pile cap level, overturning moment, residual bending moment, total bending moment and axial forces in Piles). It is found that in certain cases batter Piles play a beneficial role on the seismic behavior of the Pile foundation system. The performance of batter Piles depends not only on the characteristics of the earthquakes (frequency content and amplitude) but also on the type of superstructures they support. This novel experimental work provides a new experimental database to better understand the behavior of batter Pile Foundations in seismic regions.
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Centrifuge modeling of batter Pile Foundations under sinusoidal dynamic excitation
Bulletin of Earthquake Engineering, 2016Co-Authors: Zheng Li, Sandra Escoffier, Panagiotis KotronisAbstract:Batter Pile (or inclined Pile) Foundations are widely used in civil engineering structures. However, their behavior under dynamic loadings is not yet thoroughly understood. This paper presents an experimental work on the behavior of batter and vertical Piles considering dynamic soil-Pile-superstructure interactions. A series of dynamic centrifuge tests were performed using sinusoidal excitations. The influence of the base shaking (frequency content and amplitude) and of the height of the center of gravity of the superstructure is investigated. Seismic responses are analyzed considering the Pile cap displacements and forces (total base shear, overturning and residual moments, axial forces). It is found that in certain cases batter Piles play a beneficial role on the dynamic behavior of the Pile foundation system. This novel experimental work provides an important database on the behavior of batter Pile Foundations under dynamic loadings.
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Centrifuge modelling of inclined Pile Foundations under seismic actions
2014Co-Authors: Zheng Li, Sandra Escoffier, Panagiotis KotronisAbstract:Although inclined Pile Foundations are sometimes used in civil engineering structures, their behavior under seismic loadings is not yet thoroughly understood. This paper presents an experimental work on inclined Pile Foundations under earthquake loadings. Dynamic centrifuge tests are performed to investigate the influence of inclined Piles on the superstructures and to quantify the soil-structure interaction. Some key parameters are analyzed such as the residual bending moment, the total bending moment and the axial forces. It is found that in certain cases inclination plays a beneficial role to the seismic behavior of the Pile foundation system and that the presence of inclined Piles increases its natural frequency. Comparing to a vertical Pile foundation, the residual bending moment envelope curve is different and larger values are observed. This novel experimental work provides significant data to understand the behavior of inclined Pile Foundations in seismic regions.
Ross W. Boulanger - One of the best experts on this subject based on the ideXlab platform.
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Identifying interaction mechanisms for Pile Foundations in laterally spreading ground
2016Co-Authors: Ross W. Boulanger, Daniel W. Wilson, Bruce L. Kutter, Scott J. Brandenberg, Dongdong Chang, U. GulerceAbstract:Mechanisms of interaction between Pile Foundations and laterally spreading ground during earthquakes are identified based on the results of dynamic centrifuge model tests. Four aspects of interaction behavior are discussed: (1) the subgrade reaction behavior of liquefied sand, (2) the magnitude and phasing of lateral spreading loads and superstructure inertia loads, (3) the softer-than-expected lateral load transfer behavior between nonliquefied crust layers and Pile groups/caps, and (4) the restraining effect of Pile Foundations on bridge abutment displacements.
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seismic design of Pile Foundations for liquefaction effects
2007Co-Authors: Ross W. Boulanger, Scott J. Brandenberg, Dongdong Chang, Richard Armstrong, Bruce L. KutterAbstract:Procedures for the seismic design of Pile Foundations for liquefaction effects are presented with emphasis on the conditions relevant to bridges. Two local subsystems for a bridge are discussed in detail: (1) Pile groups in laterally spreading ground away from the abutments and (2) Pile groups at the abutments where the restraining or “pinning” effects of the Piles and bridge superstructure can be advantageous. The recommended design procedures involve equivalent static analyses using beam on nonlinear Winkler foundation models. Guidance for these design procedures was derived from a combination of dynamic centrifuge model tests and associated nonlinear dynamic finite element studies. The design procedures, their basis, and other issues for design of bridges for liquefaction effects are discussed.
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Pile Foundations in liquefied and laterally spreading ground during earthquakes centrifuge experiments analyses
2003Co-Authors: Ross W. Boulanger, Bruce L. Kutter, Scott J. Brandenberg, Priyanshu Singh, Dongdong ChangAbstract:This report describes a research project which addressed key needs for advancing the design of Pile Foundations in soil profiles that are susceptible to liquefaction and lateral spreading during earthquakes. The project was motivated by the extensive costs that are incurred with the construction of new Pile Foundations and the remediation of existing Foundations in areas where liquefaction and lateral spreading are of concern. The report describes and presents results from a series of large-scale dynamic centrifuge model tests designed to study the behavior of single Piles and Pile groups in a soil profile comprised of a nonliquefied crust spreading laterally over a loose saturated sand layer. It presents back-calculation of fundamental soil-Pile interaction behavior in the centrifuge tests. The report also evaluates monotonic pushover design methods against the centrifuge models, and presents nonlinear dynamic time-history analyses.
