Rocking Foundations for Building Systems - Effect of Footing Shape, Soil Environment, Embedment and Normalized Moment-to-shear Ratio PDF Download

Author: Manouchehr Hakhamaneshi
Publisher:
ISBN: 9781321608755
Category :
Languages : en
Pages :

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Book Description
This dissertation investigates the effect of footing shape, soil type, footing embedment and normalized moment-to-shear ratio on the cyclic performance of shallow footings subjected to rocking. The test results were used to validate modeling parameters and acceptance criteria of rocking shallow foundations in the new ASCE 41-13 standard. The results presented in this study are based on three series of large-scale centrifuge tests and thirty two small-scale centrifuge tests. The large tests included slow cyclic and dynamic shaking loading, but the small centrifuge tests only applied slow cyclic loading to the footings. Previous centrifuge test results have well characterized the behavior of rectangular rocking footings on sand, but few results are available for clayey ground. Gajan et al. (2005) and Deng et al. (2012) have shown that moment capacity of a rocking footing on sand can be accurately predicted using conventional equations. Tests on clay reported herein verify that the same equations hold for moment capacity of rectangular footings on clayey ground. The results reveal that for similar critical contact area ratio (ρac) and rotation demand, footings on clay settle about 20 to 40% less than those on sand. The standard ASCE 41-13 Seismic Evaluation and Retrofit of Existing Buildings includes new provisions for linear and non-linear modeling parameters and acceptance criteria for rocking shallow foundations. The new modeling parameters and acceptance criteria were largely based on model tests on rectangular rocking footings with a limited range of footing length to width ratio (L/B). New model test results are presented, including a systematic variation of L/B and also non-rectangular (H-shaped, C-shaped, and trapezoidal) footings. A tri-linear backbone curve is introduced to model the hysteretic moment-rotation behavior of rectangular and H-Shaped footings. The standard provides equations for rotational stiffness, K50, based on elasticity theory (Gazetas 1991). A simpler empirical method for obtaining the initial stiffness, K50 = 300M(c-foot), is proposed for rectangular footings, where M(c-foot) is the moment capacity of the footing. For H-shaped footings, it is found that K50 varies from 400M(c-foot) to 700M(c-foot). The new ASCE 41-13 provisions are limited to cases with M/VL > 1, which is considered to be a criteria that will ensure that the footing is rocking dominated (i.e., rocking deformations are more significant than sliding deformations). It is shown in this thesis that footings with 0.7M/VL

Author:
Publisher: OAE Publishing Inc.
ISBN:
Category : Social Science
Languages : en
Pages : 15

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Book Description
Although seismic design concepts integrated the idea of shallow rocking foundations as an effective way to dissipate the induced seismic energy, a practical design solution is yet to be established. To attain this objective, it is necessary to identify the key parameters that govern the rocking efficacy of foundation and eventually overall seismic performance of the entire structure. The primary focus of this study is to assess the key parameters such as soil type and embedment depth of footing in conjunction with varying rocking foundation efficacy on the seismic force and displacement demands of the Reinforced Concrete (RC) buildings. A simplified generic high rise RC building along with its foundation is considered for the analytical study which is designed and detailed as per relevant Indian Standards. To highlight the beneficial effects of rocking foundation, seismic responses of the RC buildings with varying foundation rocking efficacy are compared with the conventional foundation design philosophies by conducting nonlinear dynamic time history analyses. From the seismic responses, it is determined that the moment from column to foundation and base shear, owing to seismic action, decreases with an increasing settlement at the base of the foundation for rocking footing. It is also observed from the seismic responses that rocking foundations effectively de-amplifies the peak roof acceleration by utilizing the nonlinear soil responses during earthquakes. Hence, it can be depicted that the foundation rocking improves the overall stability of the buildings by decreasing the seismic force demands with a slight increase in seismic displacement demands. The investigation also indicates that the efficacy of rocking foundation is not sensitive to embedment depth of footing.

Author: R. Manoj Kannan
Publisher: OAE Publishing Inc.
ISBN:
Category : Social Science
Languages : en
Pages : 15

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Book Description
Although seismic design concepts integrated the idea of shallow rocking foundations as an effective way to dissipate the induced seismic energy, a practical design solution is yet to be established. To attain this objective, it is necessary to identify the key parameters that govern the rocking efficacy of foundation and eventually overall seismic performance of the entire structure. The primary focus of this study is to assess the key parameters such as soil type and embedment depth of footing in conjunction with varying rocking foundation efficacy on the seismic force and displacement demands of the Reinforced Concrete (RC) buildings. A simplified generic high rise RC building along with its foundation is considered for the analytical study which is designed and detailed as per relevant Indian Standards. To highlight the beneficial effects of rocking foundation, seismic responses of the RC buildings with varying foundation rocking efficacy are compared with the conventional foundation design philosophies by conducting nonlinear dynamic time history analyses. From the seismic responses, it is determined that the moment from column to foundation and base shear, owing to seismic action, decreases with an increasing settlement at the base of the foundation for rocking footing. It is also observed from the seismic responses that rocking foundations effectively de-amplifies the peak roof acceleration by utilizing the nonlinear soil responses during earthquakes. Hence, it can be depicted that the foundation rocking improves the overall stability of the buildings by decreasing the seismic force demands with a slight increase in seismic displacement demands. The investigation also indicates that the efficacy of rocking foundation is not sensitive to embedment depth of footing.

Author: Duncan C. Wyllie
Publisher: CRC Press
ISBN: 0203477677
Category : Architecture
Languages : en
Pages : 457

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Book Description
This second edition of the successful Foundations on Rock presents an up-to-date practical reference book describing current engineering practice in the investigation, design and construction of foundations on rock. An extra chapter on Tension Foundations has been included. The methods set out are readily applicable to high rise buildings, bridges, dams and structures subject to uplift and turning loads. Foundations on Rock differs from the many texts and handbooks on soil foundations in that it focuses on the effect of geology on the stability and settlement of rock foundations. While the intact rock may be strong, defects in the rock such as faults, joints and cavities, and the deterioration of the rock with time, will have a significant effect on foundation performance. Methods of detecting such defects are described, and their implications for foundation design and treatment are elaborated.

Author: Rolando P. Orense
Publisher: CRC Press
ISBN: 0203838203
Category : Technology & Engineering
Languages : en
Pages : 258

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Book Description
Soil-Foundation-Structure Interaction contains selected papers presented at the International Workshop on Soil-Foundation-Structure Interaction held in Auckland, New Zealand from 26-27 November 2009. The workshop was the venue for an international exchange of ideas, disseminating information about experiments, numerical models and practical en

Author: Yung Ming Cheng
Publisher: CRC Press
ISBN: 1000194027
Category : Technology & Engineering
Languages : en
Pages : 611

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Book Description
Analysis, Design and Construction of Foundations outlines methods for analysis and design of the construction of shallow and deep foundations with particular reference to case studies in Hong Kong and China, as well as a discussion of the methods used in other countries. It introduces the main approaches used by geotechnical and structural engineers, and the precautions required for planning, design and construction of foundation structures. Some computational methods and computer programmes are reviewed to provide tools for performing a more realistic analysis of foundation systems. The authors examine in depth the methods used for constructing shallow foundations, deep foundations, excavation and lateral support systems, slope stability analysis and construction, and ground monitoring for proper site management. Some new and innovative foundation construction methods are also introduced. It is illustrated with case studies of failures and defects from actual construction projects. Some advanced and modern theories are also covered in this book. This book is more targeted towards the understanding of the basic behavior and the actual construction of many geotechnical works, and this book is not dedicated to any design code or specification, though Euro codes and Hong Kong code are also used in this book for illustration. It is ideal for consulting geotechnical engineers, undergraduate and postgraduate students.

Author: A. Myslivec
Publisher: Elsevier
ISBN: 0444600515
Category : Technology & Engineering
Languages : en
Pages : 238

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Book Description
The Bearing Capacity of Building Foundations describes the different ways of ultimate bearing capacity determination of building foundations. This four-chapter book considers the effect of a horizontal force acting on a foundation. It also examines a situation where, beneath the foundation level in the zone of influence of the foundation there are two layers of soil, including the case where the second, lower layer is formed by incompressible rock. A chapter explores the case where the subgrade consists of a number of heterogeneous strata of soil. The remaining chapters deal with the determination of the permissible load of a foundation and the safety factor, and also the contact stress in the foundation line, since this has a great influence on the dimensioning of foundation slabs. This book will prove useful to practicing civil engineers.

Author: Weian Liu
Publisher:
ISBN: 9781303810626
Category :
Languages : en
Pages : 349

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Book Description
To date, experimental studies have illustrated that foundation rocking can advantageously provide an isolation mechanism, dissipating energy, and re-centering of building-foundation systems. It is hypothesized that by balancing the beneficial attributes of foundation rocking and inelastic structural behavior (structural fuse), a building-foundation system's seismic performance can be significantly improved. This dissertation validates this hypothesis from three distinct, yet complementary aspects. The first two involve a pair of system-level experiments focused on low-rise moment-resisting frame and frame-wall structural systems at centrifuge scale, while the last is completed via numerical analyses. For each of the test programs, three fundamental model configurations were constructed considering the strength difference between the rocking foundation and the structural fuse, namely; Structural Hinging Dominated (SHD), Foundation Rocking Dominated (FRD), and Balanced Design (BD) models. All model specimens were subjected to a sequence of earthquake loading. Experimental results indicate that the SHD models consistently observe the largest building residual drifts and peak roof accelerations, while the FRD models consistently observe the largest footing settlement. The BD models, however, are able to recover and report negligible residual displacements. Importantly, dissipated energy is well distributed amongst the structural fuses and the rocking footings in the BD systems. The frame-wall system test also highlights the significant impacts of seismic-induced axial load variation and building asymmetry on seismic performance. With the rocking wall placed at the far end of the lateral load resisting path, loading towards the strong (wall) direction dramatically reduces axial load on the interior rocking footing. This reduction leads to a highly asymmetric footing moment-rotation hysteresis with a "bend-over" behavior. Moreover, system-level load-carrying capacity varies significantly between the weak and strong directions. In the final phase of this research, two parameters, defined as the energy dissipation ratio (R/ED) and the re-centering ratio (R/RC), are proposed to quantify the ability of an inelastic system to dissipate hysteretic energy and to recover from large amplitude transient displacements, respectively. The relation between the R/ED and R/RC is investigated by numerically studying a variety of simplified inelastic systems under cyclic loading. Results of these analyses indicate that balancing the strength between the rocking foundation and the structural fuse allows the hybrid system to benefit from the positive attributes of each inelastic mechanism, further substantiating findings from the test programs.

Author: Indrajit Chowdhury
Publisher: CRC Press
ISBN: 1000833461
Category : Technology & Engineering
Languages : en
Pages : 427

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Book Description
The second part of this well-illustrated guide is dedicated to applications in various civil engineering problems related to dynamic soil-structure interaction, machine foundation and earthquake engineering. The book presents innovative, easy-to-apply, and practical solutions to various problems and difficulties that a design engineer will encounter. The book focuses on dynamic soil-structure interaction (DSSI), the analysis and design of machine foundations, and the analytical and design concepts for earthquake engineering.

Author: Richard G. Ahlvin
Publisher: John Wiley & Sons
ISBN: 9780471804864
Category : Technology & Engineering
Languages : en
Pages : 314

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Book Description
Other volumes in the Wiley Series of Practical Construction Guides, edited by M.D. Morris, P.E. Construction of and on Compacted Fills Edward J. Monahan Offers practical and useful information for all those involved in the planning, specifications, and execution of earthwork construction. Aimed at showing practitioners in this field, from the architect to the fill inspector, how to avoid costly and potentially dangerous losses due to defective earth structures or fills. Aimed specifically at the nonspecialists who are routinely involved but do not consult with geotechnical specialists. 1986 (0471-87463-9) 200 pp. Construction Dewatering A Guide to Theory and Practice J. Patrick Powers Here are practical solutions to the problems of ground water control based on an amalgam of theory and practice from the author's more than 30 years' experience working on major construction and mining projects. Among the subjects covered are geology of soils, soil characteristics, hydrology of aquifers, hydrologic analysis of dewatering systems, piezometers, pumping tests, geotechnical investigation of dewatering, pump theory, ground water chemistry, piping systems, selecting a dewatering method, sumps drains, deep well systems, well-point systems, and more. 1981 (0471-69591-2) 484 pp. Construction Glossary An Encyclopedic Reference and Manual J. Stewart Stein In this reference/manual, J. Stewart Stein, AIA, FCSI, puts his extensive first-hand experience to use to help construction industry professionals through the maze of multiple meanings, historical references, and technical jargon in the construction language. The material is formatted to follow the 16 major divisions of the Construction Specifications Institute's Master Format and the Uniform Construction index's specifications format. 1986 (0471-85736-X) 1,013 pp. Paper Construction of Drilled Pier Foundations David M, Greet and William S. Gardner ".an authoritative and useful work of reference for engineers, geologists, contractors and all those who need to improve their knowledge of the equipment and techniques for bored piling and of the specifications controlling their use." --Geotechnique Focusing on foundation types, construction methods and quality control, Construction of Drilled Pier Foundations is the first of a two-volume reference that will update and expand on the groundwork established by the 15-year-old Drilled Pier Foundations. It is comprehensive, detailed, and up-to-date, with current techniques, equipment, and practice. 1986 (0471-82881-5) 246 pp.