Author: Liangcai He
Publisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 418

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Book Description

Author: Jinchi Lu
Publisher:
ISBN:
Category :
Languages : en
Pages : 359

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Book Description
Parallel computing is gradually becoming a main stream tool in geotechnical simulations. The need for high fidelity and for modeling of fairly large 3-dimensional (3D) spatial configurations is motivating this direction of research. The main objective of this thesis is to develop a state-of-the-art nonlinear parallel finite element program for earthquake ground/structure response and liquefaction simulation. In the developed parallel code, ParCYCLIC, finite elements are employed within an incremental plasticity, coupled solid-fluid formulation. A constitutive model calibrated by physical tests represents the salient characteristics of sand liquefaction and associated accumulation of shear deformations. Key elements of the computational strategy employed in ParCYCLIC include the development of a parallel sparse direct solver, the deployment of an automatic domain decomposer, and the use of the Multilevel Nested Dissection algorithm for ordering of the finite element nodes. Conducted large-scale geotechnical simulations show that ParCYCLIC is efficiently scalable to a large number of processors. Calibrated FE simulations are increasingly providing a reliable environment for modeling liquefaction-induced ground deformation. Effects on foundations and super-structures may be assessed, and associated remediation techniques may be explored, within a unified framework. Current capabilities of such a FE framework are demonstrated via a series of 3-dimensional (3D) simulations. High-fidelity 3D numerical studies using ParCYCLIC are shown to provide more accurate results. Much time and effort is expended today in building an appropriate finite element mesh and associated data files. User-friendly interfaces can significantly alleviate this problem allowing for high efficiency and much increased confidence. Pre- and post processing interfaces are developed to facilitate use of otherwise computational environments with numerous (often vaguely defined) input parameters. User-friendly interfaces are useful not only for simple model simulations on single-processor computers but also for large-scale modeling on a parallel machine.

Author: Zhaohui Yang
Publisher:
ISBN:
Category : Shear (Mechanics)
Languages : en
Pages : 286

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Book Description

Author: Rui Wang
Publisher: Springer
ISBN: 3662496631
Category : Science
Languages : en
Pages : 131

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Book Description
This thesis focuses on the seismic response of piles in liquefiable ground. It describes the design of a three-dimensional, unified plasticity model for large post-liquefaction shear deformation of sand, formulated and implemented for parallel computing. It also presents a three-dimensional, dynamic finite element analysis method for piles in liquefiable ground, developed on the basis of this model,. Employing a combination of case analysis, centrifuge shaking table experiments and numerical simulations using the proposed methods, it demonstrates the seismic response patterns of single piles in liquefiable ground. These include basic force-resistance mode, kinematic and inertial interaction coupling mechanism and major influence factors. It also discusses a beam on the nonlinear Winkler foundation (BNWF) solution and a modified neutral plane solution developed and validated using centrifuge experiments for piles in consolidating and reconsolidating ground. Lastly, it studies axial pile force and settlement during post-earthquake reconsolidation, showing pile axial force to be irrelevant in the reconsolidation process, while settlement is process dependent.

Author: National Academies of Sciences, Engineering, and Medicine
Publisher:
ISBN: 9780309440271
Category :
Languages : en
Pages : 350

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Book Description
Earthquake-induced soil liquefaction (liquefaction) is a leading cause of earthquake damage worldwide. Liquefaction is often described in the literature as the phenomena of seismic generation of excess porewater pressures and consequent softening of granular soils. Many regions in the United States have been witness to liquefaction and its consequences, not just those in the west that people associate with earthquake hazards. Past damage and destruction caused by liquefaction underline the importance of accurate assessments of where liquefaction is likely and of what the consequences of liquefaction may be. Such assessments are needed to protect life and safety and to mitigate economic, environmental, and societal impacts of liquefaction in a cost-effective manner. Assessment methods exist, but methods to assess the potential for liquefaction triggering are more mature than are those to predict liquefaction consequences, and the earthquake engineering community wrestles with the differences among the various assessment methods for both liquefaction triggering and consequences. State of the Art and Practice in the Assessment of Earthquake-Induced Soil Liquefaction and Its Consequences evaluates these various methods, focusing on those developed within the past 20 years, and recommends strategies to minimize uncertainties in the short term and to develop improved methods to assess liquefaction and its consequences in the long term. This report represents a first attempt within the geotechnical earthquake engineering community to consider, in such a manner, the various methods to assess liquefaction consequences.

Author: Nima Tafazzoli
Publisher:
ISBN: 9781267663160
Category :
Languages : en
Pages :

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Book Description
Seismic response of soil-structure systems has attracted significant attention for a long time. This is quite understandable with the size and the complexity of soil-structure systems. The focus of three important aspects of ESSI modeling could be on consistent following of input seismic energy and a number of energy dissipation mechanisms within the system, numerical techniquesused to simulate dynamics of ESSI, and influence of uncertainty of ESSI simulations. This dissertation is a contribution to development of one such tool called ESSI Simulator. The work is being done on extensive verified and validated suite for EESI Simulator. Verification and validation are important for high fidelity numerical predictions of behavior of complex systems. This simulator uses finite element method as a numerical tool to obtain solutions for large class of engineering problems such as liquefaction, earthquake-soil-structure-interaction, site effect, piles, pile group, probabilistic plasticity, stochastic elastic-plastic FEM, and detailed large scale parallel models. Response of full three-dimensional soil-structure-interaction simulation of complex structures is evaluated under the 3D wave propagation. Domain-Reduction-Method is used for applying the forces as a two-step procedure for dynamic analysis with the goal of reducing the large size computational domain. The issue of damping of the waves at the boundary of the finite element models is studied using different damping patterns. This is used at the layer of elements outside of the Domain-Reduction-Method zone in order to absorb the residual waves coming out of the boundary layer due to structural excitation. Extensive parametric study is done on dynamic soil-structure-interaction of a complex system and results of different cases in terms of soil strength and foundation embedment are compared. High efficiency set of constitutive models in terms of computational time are developed and implemented in ESSI Simulator. Efficiency is done based on simplifying the elastic-plastic stiffness tensor of the constitutive models. Almost in all the soil-structure systems, there are interface zones in contact with each other. These zones can get detached during the loading or can slip on each other. In this dissertation the frictional contact element is implemented in ESSI Simulator. Extended verification has been done on the implemented element. The interest here is the effect of slipping and gap opening at the interface of soil and concrete foundation on the soil-structure system behavior. In fact transferring the loads to structure is defined based on the contact areas which will affect the response of the system. The effect of gap openings and sliding at the interfaces are shown through application examples. In addition, dissipation of the seismic energy due to frictional sliding of the interface zones are studied. Application Programming Interface (API) and Domain Specific Language (DSL) are being developed to increase developer's and user's modeling and simulation capabilities. API describes software services developed by developers that are used by users. A domain-specific language (DSL) is a small language which usually focuses on a particular problem domain in software. In general DSL programs are translated to a common function or library which can be viewed as a tool to hide the details of the programming, and make it easier for the user to deal with the commands.

Author: Ikuo Towhata
Publisher: Springer Science & Business Media
ISBN: 3540357831
Category : Science
Languages : en
Pages : 684

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Book Description
This fascinating new book examines the issues of earthquake geotechnical engineering in a comprehensive way. It summarizes the present knowledge on earthquake hazards and their causative mechanisms as well as a number of other relevant topics. Information obtained from earthquake damage investigation (such as ground motion, landslides, earth pressure, fault action, or liquefaction) as well as data from laboratory tests and field investigation is supplied, together with exercises/questions.

Author: Madhavi Latha Gali
Publisher: Springer Nature
ISBN: 9811562334
Category : Science
Languages : en
Pages : 763

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Book Description
This volume comprises select papers presented during the Indian Geotechnical Conference 2018. This volume discusses concepts of soil dynamics and studies related to earthquake geotechnical engineering, slope stability, and landslides. The papers presented in this volume analyze failures connected to geotechnical and geological origins to improve professional practice, codes of analysis and design. This volume will prove useful to researchers and practitioners alike.

Author: Nozomu Yoshida
Publisher: Springer
ISBN: 940179460X
Category : Science
Languages : en
Pages : 370

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Book Description
This book presents state-of-the-art information on seismic ground response analysis, and is not only very valuable and useful for practitioners but also for researchers. The topics covered are related to the stages of analysis: 1. Input parameter selection, by reviewing the in-situ and laboratory tests used to determine dynamic soil properties as well as the methods to compile and model the dynamic soil properties from literature;2. Input ground motion; 3. Theoretical background on the equations of motion and methods for solving them; 4. The mechanism of damping and how this is modeled in the equations of motions; 5. Detailed analysis and discussion of results of selected case studies which provide valuable information on the problem of seismic ground response analysis from both a theoretical and practical point of view.

Author: M. Hori
Publisher: CRC Press
ISBN: 1000615774
Category : Technology & Engineering
Languages : en
Pages : 192

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Book Description
Integrated earthquake simulation (IES) is a new method for evaluating earthquake hazards and disasters induced in cities and urban areas. It utilises a sequence of numerical simulations of such aspects as earthquake wave propagation, ground motion amplification, structural seismic response, and mass evacuation. This book covers the basics of numerical analysis methods of solving wave equations, analyzing structural responses, and developing agent models for mass evaluation, which are implemented in IES. IES makes use of Monte-Carlo simulation, which takes account of the effects of uncertainties related to earthquake scenarios and the modeling of structures both above and below ground, and facilitates a better estimate of overall earthquake and disaster hazard. It also presents the recent achievement of enhancing IES with high-performance computing capability that can make use of automated models which employ various numerical analysis methods. Detailed examples of IES for the Tokyo Metropolis Earthquake and the Nankai Trough Earthquake are given, which use large scale analysis models of actual cities and urban areas.