Modeling of Retrofitting Strategies to Remediate the Effect of Seismically Induced Lateral Spreading of Pile Foundations PDF Download

Author: Yingjuan Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 188

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Author: Tarek Hassan Abdoun
Publisher:
ISBN:
Category : Centrifugation
Languages : en
Pages : 356

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Author: Liangcai He
Publisher:
ISBN:
Category :
Languages : en
Pages : 886

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

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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: Ahmed Amr Ebeido
Publisher:
ISBN:
Category :
Languages : en
Pages : 485

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Current techniques for assessing the effects of liquefaction-induced lateral spreading on pile foundations are based on simplified analytical methods that potentially lead to estimates that vary within a wide range. This might lead to potential excessive design demands, with high expenses for pre-event mitigation. Conversely, underestimated design demands might lead to costly post-event damage remediation. The conducted study is directed towards enhancements to the assessment of liquefaction induced lateral spreading effects on bridge foundation systems. Current simplified analysis techniques have been only been developed recently in preliminary form. In addition, quantitative data sets from large-scale experimentation are needed concerning the response of such ground-foundation scenarios. An effort was undertaken to address the simplified method areas of applicability and potential for enhancements. Challenges in implementing the methodology are presented within a comparative scope contrasting results of a California bridge site from different studies. On this basis, insights are derived for improvement of the currently employed simplified analysis guidelines. Furthermore, large scale shake table testing was performed on pile foundation-ground systems, under conditions of liquefaction-induced lateral spreading. A total of 7 different experiments were conducted with varying heights, ground inclination, soil profiles, pile material and cross-section. The tested models were densely instrumented, including strain gauges, total pressure and excess pore-pressure sensors, accelerometers and displacement pots. In addition, data from 4 different experiments conducted in the NIED Japan shake table facility, including single piles and pile groups and varying soil profiles were utilized to provide additional insights and characteristics. In these tests, the laminar soil container was placed in a mildly-inclined configuration to allow for accumulation of the liquefaction-induced lateral deformations. Detailed instrumentation and data interpretation procedures enable measurement of the fundamental soil-pile interaction behavior. The loading mechanisms have large cyclic components that may act in-phase or out-of-phase along the pile embedded length. The conducted heavily instrumented tests resulted in a wealth of quantitative response data sets, to be used for: i) drawing insights and recommendations of practical significance based directly on the observed response, ii) calibration of simplified and more elaborate computational analysis tools, and iii) enhancement of our design guidelines and practical assessment procedures. Monotonic pushover analysis based on newly derived p-y curves in this study is found to provide useful design estimates in good agreement with the observed experimental results.

Author: Ross W. Boulanger
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 344

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Proceedings of a workshop on Seismic Performance and Simulation of Pile Foundations in Liquefied and Laterally Spreading Ground, held in Davis, California, March 16-18, 2005. Sponsored by the Pacific Earthquake Engineering Research Center; University of California at Berkeley; Center for Urban Earthquake Engineering; Tokyo Institute of Technology; Geo-Institute of ASCE. This collection contains 25 papers that discuss physical measurements and observations from earthquake case histories, field tests in blast-liquefied ground, dynamic centrifuge model studies, and large-scale shaking table studies. Papers contain recent findings on fundamental soil-pile interaction mechanisms, numerical analysis methods, and reviews and evaluations of existing and emerging design methodologies. This proceeding provides comprehensive coverage of a major issue in earthquake engineering practice and hazard mitigation efforts.

Author: John Charles Horne
Publisher:
ISBN:
Category : Piling (Civil engineering)
Languages : en
Pages : 742

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Author: Lenart Luis Gonzalez Lagos
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 392

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Author: Arash Khosravifar
Publisher:
ISBN: 9781267402622
Category :
Languages : en
Pages :

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Experiences from past earthquakes have shown that lateral spreading associated with liquefaction of cohesionless soils can be a cause of severe damage to bridge foundations. Large diameter extended pile shafts can be an effective bridge foundation choice for areas subjected to lateral spreading because they offer greater stiffness and strength relative to the magnitude of lateral spreading loads that can develop against them. A limited degree of plastic hinging below the ground surface may be allowable in design of extended pile shafts. Issues for design for extended pile shafts include: (a) how to estimate the demands due to superstructure inertia and lateral spreading in liquefied soils, and (b) how to combine these two loads in estimating the local and global inelastic demands on the structure. Studies of the response of pile foundations and pile-supported structures in liquefiable soils using physical models, numerical models, and case studies have provided the basis for a number of design recommendations. The guidance is, however, quite varied regarding how lateral spreading and superstructure inertial loads should be combined in design. To answer the above questions a series of Nonlinear Dynamic Finite Element Analyses (NDA) have been performed to investigate inelastic response of extended pile shafts subjected to liquefaction-induced lateral spreading, covering a range of soil, pile, and ground motion conditions. The results of NDA were first used to show that combined effects of lateral spreading and superstructure inertia produce larger demands than are produced by either loading case alone, such that the combined demand cannot be enveloped by analyzing the two load cases separately. The results were then used to evaluate current equivalent static analysis (ESA) method (Caltrans, 2008), with the relatively poor agreement illustrating the limitations of methods that do not combine the two loads. The results of NDA parametric study were then used to develop and calibrate an ESA procedure. The ESA procedure addresses both the nonliquefaction and liquefaction cases, and includes criteria that identify conditions which tend to produce excessive demands or collapse conditions. Finally, a series of three-dimensional (3D) Nonlinear Dynamic Finite Element Analyses (NDA) were performed to examine inelastic behavior of large diameter extended pile shafts subjected to earthquake shaking and liquefaction-induced lateral spreading. The purpose of these analyses was to evaluate the differences between 2D and 3D simulations, understand the source of any differences, and evaluate whether those differences would affect design recommendations for Equivalent Static Analysis (ESA).

Author: Marcelo Alejandro Gonzalez
Publisher:
ISBN: 9781109141818
Category :
Languages : en
Pages : 422

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