scholarly journals Seismic Behaviour of Piles in Non-Liquefiable and Liquefiable Soil

2021 ◽  
Author(s):  
Fouad Hussein ◽  
Hesham El Naggar
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Numerical Models ◽  
Bending Moment ◽  
Shaking Table ◽  
Pile Groups ◽  
Seismic Behaviour ◽  
Kinematic Interaction ◽  
Inertial Interaction ◽  
Liquefiable Soil

Abstract This paper investigates the nonlinear soil-pile-structure interaction (SPSI) employing three-dimensional (3D) nonlinear finite element (FE) models verified with the results of large-scale shaking table tests of model pile groups-superstructure systems. The responses of piles in both liquefiable and non-liquefiable soil sites to ground motion with varying intensities were evaluated considering both kinematic and inertial interaction. The calculated piles and soil responses agreed well with the responses measured during the shaking events. The numerical models correctly predicted the different pile deformation modes that were exhibited in the experiments. The FEA was then employed to perform a parametric study to evaluate the kinematic and inertial effects on the piles' response considering different ground motion levels and piles characteristics. It was found that the bending moment of piles in the liquefiable site increases significantly, compared to the non-liquefiable site, due to the loss of lateral support of the liquified soil, and the maximum bending moment occurs at the interface between the liquified and non-liquefied sand layers. The inertial interaction contributes the most to the bending moments at the pile top and the interface between the top clay and liquefied loose sand layers. For piles with a larger diameter, the bending moment due to kinematic interaction increases significantly and the bending moment distribution corresponds to short (rigid) pile behaviour. In addition, the piles at the saturated site displace laterally as a rigid body during strong ground motions because the pile base loses the lateral support due to the liquefaction of the bottom dense sand. Finally, the kinematic interaction effect becomes more significant for piles with higher elastic modulus.

scholarly journals Seismic Behaviour of Piles in Non-Liquefiable and Liquefiable Soil

2021 ◽  
Author(s):  
Fouad Hussein ◽  
Hesham El Naggar
Keyword(s):  
Finite Element ◽  
Ground Motion ◽  
Numerical Models ◽  
Bending Moment ◽  
Soil Liquefaction ◽  
Shaking Table ◽  
Pile Groups ◽  
Kinematic Interaction ◽  
Inertial Interaction ◽  
Liquefiable Soil

Abstract This paper investigates the nonlinear soil-pile-structure interaction (SPSI) employing three-dimensional (3D) nonlinear finite element models (FEM) verified with the results of large-scale shaking table tests of model pile groups-superstructure systems. The responses of piles in both liquefiable and non-liquefiable soil sites to ground motion with varying intensities were evaluated considering both kinematic and inertial interaction. The calculated piles and soil responses agreed well with the responses measured during the shaking events. The numerical models correctly predicted the different pile deformation modes that were exhibited in the experiments. The finite element analysis (FEA) was then employed to perform a parametric study to evaluate the kinematic and inertial effects on the piles' response, considering different ground motion levels and piles characteristics. It was found that the bending moment of piles in the liquefiable site increases significantly, compared to the non-liquefiable site, due to the loss of lateral support of the liquified soil, and the maximum bending moment occurs at the interface between the liquified and liquefied sand layers. The inertial interaction contributes the most to the bending moments at the pile top and the interface between the top clay and liquefied loose sand layers. For piles with a larger diameter, the bending moment due to kinematic interaction increases significantly, and the bending moment distribution corresponds to short (rigid) pile behaviour. In addition, the piles at the saturated site displace laterally as a rigid body during strong ground motions because the pile base loses the lateral support due to the soil liquefaction. Finally, the kinematic interaction effect becomes more significant for piles with higher elastic modulus.

Centrifuge Modeling on Seismic Behavior of Pile in Liquefiable Soil Ground

2013 ◽  
Vol 479-480 ◽  
pp. 1139-1143
Author(s):  
Wen Yi Hung ◽  
Chung Jung Lee ◽  
Wen Ya Chung ◽  
Chen Hui Tsai ◽  
Ting Chen ◽  
...  
Keyword(s):  
Seismic Behavior ◽  
Soil Structure ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Soil Liquefaction ◽  
Centrifuge Modeling ◽  
Shaking Table ◽  
Pile Head ◽  
Liquefiable Soil ◽  
Tip Mass

Dramatic failure of pile foundations caused by the soil liquefaction was founded leading to many studies for investigating the seismic behavior of pile. The failures were often accompanied with settlement, lateral displacement and tilting of superstructures. Therefore soil-structure interaction effects must be properly considered in the pile design. Two tests by using the centrifuge shaking table were conducted at an acceleration field of 80 g to investigate the seismic response of piles attached with different tip mass and embedded in liquefied or non-liquefied deposits during shaking. It was found that the maximum bending moment of pile occurs at the depth of 4 m and 5 m for dry sand and saturated sand models, respectively. The more tip mass leads to the more lateral displacement of pile head and the more residual bending moment.

Seismic Response of Pile Groups Improved with Deep Cement mixing Columns in Liquefiable Sand: Shaking Table Tests

2021 ◽  
Author(s):  
Dingwen Zhang ◽  
Anhui Wang ◽  
Xuanming Ding
Keyword(s):  
Seismic Behavior ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Pile Group ◽  
Shaking Table ◽  
Excess Pore Pressure ◽  
Shaking Table Tests ◽  
Pile Groups ◽  
Acceleration Response ◽  
Table Model

A series of shaking table model tests were performed to examine the effects of deep cement mixing (DCM) columns with different reinforcement depths on the seismic behavior of a pile group in liquefiable sand. Due to the DCM column reinforcement, the fundamental natural frequency of the model ground increases noticeably. The excess pore pressure of soils reduces with the increase of reinforcement depths of the DCM columns. Before liquefaction, the acceleration response of soils in the improved cases is obviously lower than that in the unimproved case, but the acceleration attenuation is greater after liquefaction in the unimproved case. Moreover, the lateral displacement of the superstructure, the settlement of the raft, and the bending moment of the piles in the improved cases are significantly reduced compared to those in the unimproved case, and the reduction ratios rise with the increase of reinforcement depth of the DCM columns. However, reinforcement by the DCM columns may result in the variation of the location of the maximum moment that occurs in the pile.

Effects of Damper Force Ranges and Ground Motion Pulse Periods on the Performance of Semi-Active Isolation Systems

2003 ◽  
Author(s):  
Henri Gavin ◽  
Julie Thurston ◽  
Chicahiro Minowa ◽  
Hideo Fujitani
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Base Isolation ◽  
Near Field ◽  
Shaking Table ◽  
Isolation System ◽  
Active Isolation ◽  
Isolation Systems ◽  
Fail Safe ◽  
Strong Ground

A large-scale base-isolated steel structural frame was tested at the shaking table laboratory of the National Research Institute for Earth Sciences and Disaster Prevention. These collaborative experiments featured auto-adaptive media and devices to enhance the performance of passive base isolation systems. The planning of these experiments involved determining appropriate device control methods, the development of a controllable damping device with fail-safe characteristics, and the evaluation of the performance of the controlled isolation system subjected to strong ground motion with pronounced near-field effects. The results of the planning study and their large-scale experimental confirmation provide guidelines for the development and implementation of auto-adaptive damping devices for full scale structures.

Evaluation of Aseismic Reliability of Actual Boiler Structures and a Study on Design of Seismic Ties Based on Proof Tests Using a Large Scaled Shaking Table

2004 ◽  
Vol 126 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Kiyoshi Aida ◽  
Yasuyuki Owa ◽  
Kohei Suzuki ◽  
Satoshi Fujita
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Coupled Model ◽  
Shaking Table ◽  
Response Analysis ◽  
Simulation Methods ◽  
Support Structures ◽  
Boiler Plant ◽  
Structure Interaction ◽  
Energy Absorbing

This paper deals with the evaluation of aseismic reliability of actual boiler plant structures in conjunction with seismic ties, installed between the boiler and the support structures. Proof tests were conducted with a coupled model using a large-scale shake table which verified that the ties acted as energy-absorbing devices against severe earthquakes. Since recent boiler structures are designed based on dynamic response analysis considering the boiler-structure interaction and the effect of energy dissipation of the ties, it is necessary to verify the accuracy of simulation methods. In view of this, the numerical models of the ties are discussed in post analysis. As a result of the post analysis, it is confirmed that (1) seismic ties of existing boiler plants designed by dynamic analysis provide sufficient durability, and (2) the support structures designed by conventional methods have enough aseismic reliability.

scholarly journals Seismic performance analysis of a wind turbine tower subjected to earthquake and ice actions

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247557
Author(s):  
Shuai Huang ◽  
Yuejun Lyu ◽  
Liwei Xiu ◽  
Haijun Sha
Keyword(s):  
Sea Ice ◽  
Wind Turbine ◽  
Seismic Performance ◽  
Shear Force ◽  
Shaking Table Test ◽  
Bending Moment ◽  
Shaking Table ◽  
Seismic Behaviour ◽  
Wind Turbine Tower ◽  
Calculated Model

Sea ice is one of the main loads acting on a wind turbine tower in areas prone to icing, and this threatens safe working life of the wind turbine tower. In our study, a simplified calculated model of ice, wind turbine tower, and water dynamic interaction under earthquake action was proposed, which could avoid to solve a large number of nonlinear equations. Then, the seismic behaviour of the wind turbine tower with and without the influence of sea ice was investigated, and we found that the influence of the greater mass of the sea ice on the seismic response of a wind turbine tower should be considered when the wind turbine tower is designed in an area with thick ice. With the influence of the most unfavourable ice mass, the deformation and energy dissipation capacity of the wind turbine tower are decreased, and the wall thickness or stiffening rib thickness should be increased to improve the seismic performance and ductility of the wind turbine tower; the shear force and bending moment increased significantly on the wind turbine tower, and the shear force changes at the bottom of the wind turbine tower and position of action of the sea ice: attention should be paid to the wind turbine tower design at these positions. Finally, we conducted the shaking table test, and verified the rationality of our proposed simplified model.

scholarly journals Vanadium Redox Flow Batteries: A Review Oriented to Fluid-Dynamic Optimization

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 176
Author(s):  
Iñigo Aramendia ◽  
Unai Fernandez-Gamiz ◽  
Adrian Martinez-San-Vicente ◽  
Ekaitz Zulueta ◽  
Jose Manuel Lopez-Guede
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Fluid Dynamic ◽  
Renewable Energy Sources ◽  
Vanadium Redox Flow Battery ◽  
Redox Flow Batteries ◽  
Design Flexibility ◽  
Flow Batteries ◽  
Exchange Membrane ◽  
Vanadium Redox

Large-scale energy storage systems (ESS) are nowadays growing in popularity due to the increase in the energy production by renewable energy sources, which in general have a random intermittent nature. Currently, several redox flow batteries have been presented as an alternative of the classical ESS; the scalability, design flexibility and long life cycle of the vanadium redox flow battery (VRFB) have made it to stand out. In a VRFB cell, which consists of two electrodes and an ion exchange membrane, the electrolyte flows through the electrodes where the electrochemical reactions take place. Computational Fluid Dynamics (CFD) simulations are a very powerful tool to develop feasible numerical models to enhance the performance and lifetime of VRFBs. This review aims to present and discuss the numerical models developed in this field and, particularly, to analyze different types of flow fields and patterns that can be found in the literature. The numerical studies presented in this review are a helpful tool to evaluate several key parameters important to optimize the energy systems based on redox flow technologies.

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