Dissertations / Theses: 'Soil-structure interaction; Foundations'

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Heron, Charles Michael. "The dynamic soil structure interaction of shallow foundations on dry sand beds." Thesis, University of Cambridge, 2014. https://www.repository.cam.ac.uk/handle/1810/265576.

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The design of shallow foundations located in seismically active zones typically takes a near zero tolerance approach to allowing relative movements between the foundation and underlying soil. This results in a rigid coupling of the foundation with the soil and hence the full transmission of the seismic energy into the foundation. Consequently the structure located on the foundation either has to be isolated from the shaking through manufactured damping systems or designed to withstand the full force of the dynamic shaking while the energy is dissipated through structural damping. There is, however, an increasing focus on reducing the coupling between the soil and foundation which consequently reduces the demands on the structure. Allowing the foundation to slide and/or rock isolates the foundation from the dynamic shaking and helps to dissipate energy through soil damping. The same level of seismic protection which is currently provided by manufactured solutions is still therefore possible but with the advantage of reduced costs and complexity in construction. This design concept has, however, not been widely adopted due to concerns regarding the possibility for excessive movement of the foundation, resulting in damage to the superstructure or overall toppling of the structure. In addition, the behaviour is currently difficult to model precisely and therefore it is challenging to quantify the exact level of seismic protection achieved. The work presented in this thesis strives to address some of these issues. A series of ten centrifuge tests were conducted on small-scale model structures founded on dry sand and subjected to a series of simulated earthquakes. The effect of a range of model parameters was investigated including relative density, bearing pressure, structural stiffness, aspect ratio, earthquake strength and earthquake frequency. For six of the tests, the movement of the soil beneath the foundation and the structure itself were monitored by analysing images collected from high speed photography (1000 frames per second) using particle image velocimetry software. In addition to the photogramrnetry, a series of miniature measurement transducers were used to record the acceleration in the soil and the structure. Displacement transducers were used to monitor the settlement of the structure and free-field. In total over one hundred earthquakes were carried out resulting in an extensive dataset, against which hypotheses and analytical models could be verified. It was found that the transition from the structure being stationary to it responding in a steady state fashion can be a critical period in which the response of the soil-foundation-structure system must be carefully analysed. The phase shift between the superstructure, foundation and soil can vary during this period. As a result, different modes of response are adopted by the system which, in certain circumstances, can result in a significant increase in the displacement magnitude experienced by the structure. The behaviour is not unexpected, as the same behaviour can be observed from the analytical analysis of a simple single degree of freedom system. Inaddition, a strong correlation between rocking, sliding and settlement was observed, with the degree of lift-off controlling the amount of settlement and sliding which takes place. A macro-element analytical model has been developed to predict the moment-rotation behaviour of shallow raft foundations. A hyperbolic model, used for predicting the stress-strain behaviour of soil, was adapted and used to create the backbone curve of the moment-rotation cycle. A modification was made to the hysteretic damping rules proposed by Masing which allows the energy dissipation to be included in the model. The model was found to mimic the experimental data accurately, with the correct prediction of the lift-off rotation magnitude, moment magnitude, small-rotation stiffness and energy dissipation. Finally, the soil deformation mechanism was observed and analysed. It was found that in some scenarios, when the strain level within the deformation mechanism was low, a trapped wedge was apparent under the foundation. The trapped wedge appeared as a triangular zone of low strain (referred to in some literature as a rigid block), with the foundation located along the top edge and two distinct shear bands on either side. However, as strain magnitudes increased, the shear bands appeared to widen and resulted in strain being apparent throughout the previously unstrained wedge. One of the main differences between the theoretical mechanisms proposed in the literature is the inclusion or exclusion of such a rigid block. Given the majority of the analytical mechanisms proposed in the literature are upper bound mechanisms, and therefore are a prediction of the mechanism at failure, it is inadvisable to include the rigid wedge within the analytical mechanism given that the strain magnitudes will inevitably be large at the point of bearing failure. Given complete failure of the supporting soil did not occur during any of the centrifuge tests performed, comparisons between the observed mechanism and one of these theoretical mechanisms is difficult. However, comparisons between the experimental deformation mechanisms and one analytical failure mechanism did show that the depth of the mechanism could be relatively well predicted as could the degree of separation between the foundation and the underlying soil. This information allows design engineers to know to what depth ground should be remediated below a shallow foundation and how strong the foundation needs to be to cope with the lift-off it will experience. The insight provided by this research into the true soil deformation mechanism, combined with the development of an analytical model of the moment-rotation behaviour, paves the way for engineers to implement designs which actively make use of the beneficial characteristics of soil-structure-interaction.

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Jones, Anthony James. "Analysis of shallow and deep foundations using soil-structure interaction techniques." Thesis, University of South Wales, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.480929.

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Pérez-Herreros, Jesús. "Dynamic soil-structure interaction of pile foundations : experimental and numerical study." Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0002.

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La réponse dynamique d’une structure supportée par des fondations profondes constitue un problème complexe d’Interaction Sol-Structure (ISS). Sous chargement sismique, les pieux sont soumis à la sollicitation imposée par le sol (interaction cinématique) et aux forces d’inertie transmises par la superstructure (interaction inertielle). Le dimensionnement des fondations profondes soumises à des sollicitations sismiques est souvent réalisé au moyen de méthodes conservatrices visant à assurer que les fondations ne soient pas endommagées. La plupart de ces méthodes considèrent le comportement de la fondation élastique linéaire et par conséquent la capacité de la fondation à dissiper de l’énergie du fait des mécanismes non-linéaires est négligée. Cette approche était justifiée dans le passé en raison du manque d’informations sur le comportement non-linéaire des fondations et de l’absence d’outils numériques adaptés. De telles limitations deviennent de plus en plus obsolètes, puisqu’un nombre pertinent de résultats expérimentaux et numériques sont maintenant disponibles, ainsi que de nouvelles méthodes de conception (Pecker et al. 2012). Dans cette thèse, le comportement des pieux isolés et des groupes de pieux sous chargement sismique est étudié avec une approche couplant l’expérimental et le numérique. Des essais dynamiques en centrifugeuse sont effectués avec un sol stratifié, plusieurs configurations de fondations et une série de séismes et sollicitations sinusoïdales. Des calculs non-linéaires aux éléments finis sont également effectués et comparés aux résultats expérimentaux afin d’étudier la capacité des modèles numériques à reproduire de manière satisfaisante la réponse non-linéaire des fondations. Un nouveau macroélément pour les groupes de pieux sous chargement sismique est proposé et validé numériquement. Le macroélément permet de prendre en compte les effets de groupe et leur variation avec la fréquence de sollicitation (interaction pieu-sol-pieu) ainsi que la non-linéarité développée dans le système. Le nouveau macroélément est enfin utilisé pour effectuer une analyse dynamique incrémentale (IDA) du pylône centrale d’un pont à haubans
The dynamic response of a structure supported by pile foundations is a complex Soil-Structure Interaction (SSI) problem. Under earthquake loading, the piles are subjected to loadings due to the deformation imposed by the soil (kinematic interaction) and to the inertial forces transmitted by the superstructure (inertial interaction). The design of deep foundations under seismic loadings is often carried out by means of conservative methods that aim to assure zero damage of the foundation. Most of these methods consider the behavior of the foundation as linear elastic. As a result, the capability of the foundation to dissipate energy during seismic loading due to nonlinear mechanisms is neglected. This approach was justified in the past due to the lack of information about the nonlinear behavior of foundations and the absence of adapted numerical tools. Such limitations are becoming more and more obsolete, as a relevant number of experimental and numerical results are now available as well as new design methods (Pecker et al. 2012). In this Ph.D, the behavior of single piles and pile groups under seismic loading is studied using both experiments and finite element calculations. Dynamic centrifuge tests are carried out with a multilayered soil profile, several foundation configurations and a series of earthquakes and sinusoidal base shakings. Nonlinear finite element calculations are also performed and compared to experimental results to investigate the ability of current computational models to satisfactorily reproduce the nonlinear response of foundations. A novel macroelement for pile group foundations under seismic loading is developed and numerically validated. It allows taking into account the group effects and their variation with the loading frequency (pile-soil-pile interaction) as well as the nonlinearity developed in the system. Finally, the macroelement model for pile groups is used to perform an Incremental Dynamic Analysis (IDA) of the main pylon of a cable-stayed bridge

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Kelly, Peter. "Soil structure interaction and group mechanics of vibrated stone column foundations." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/5812/.

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The development of transparent synthetic soil has enabled non-intrusive measurement of internal soil displacement and detection of pre-failure strains using laser aided imaging and Particle Image Velocimetry. The work described in this paper applies this novel methodology to evaluate the deformation and failure behaviour of stone column foundations in reduced scale physical models. The overall accuracy and precision of the test system were optimised to 53 μm and 0-4.3μm respectively through the implementation of newly developed image enhancement and photogrammetric correction techniques. This represented a considerable improvement compared to the previous state of the art in transparent soil modeling. A total of 7 isolated column tests and 6 column strip footing tests were carried out in repeatable transparent clay beds. Visualisation of real-time internal displacement has indicated that isolated stone columns fail in an axisymmetric manner through a combination of compression and bulging with only a small amount of column base penetration, indicating a critical column length of 4d. Consequently, increasing column length from 4d to 6d and 8d lead to only moderate increases of 8.5% and 13% in bearing capacity respectively In contrast to the isolated columns, local shear failure, bulging, bending, punching and block failure were all observed for column strip foundations, depending on the geometrical configurations employed. Column length played a particularly important role in optimising the bearing capacity of column strip foundations. Increasing column length from 4d to 6d and 8d was shown to improve the load capacity of the composite foundation by 29% and 67%. It was concluded that the critical length in terms of optimising the bearing capacity of a vibro strip foundation is 8d. However, increasing foundation size rather than column length was found to be more effective in increasing the load capacity in both cases. Increasing footing size and correspondingly increasing Ar from 3 to 4 and 5 was seen to protect the upper column from bulging and increase its radial zone of influence of the column in the surrounding soil, resulting in increases in load capacity of 28% and 51% for isolated columns and 22% and 29% for strip foundations respectively. It was concluded that provision of a footing overhang of over 0.4d should prevent shear failure in vibro strip foundations. A new design approach has been proposed which accounts for the size of the footing. The performance of each isolated column foundation was predicted to within 6% of the measured load capacity for all area ratios tested, while the load capacities of the strip foundations were predicted to within 14%. Thus although the new method does not model the ‘group effect’, it offers an improvement on cavity expansion based design methods, as column structure interaction is accounted for. Overall, the nature of the configuration of vibro strip foundations and their limited size in practice limit the bearing capacity of stone columns within a strip configuration to values only slightly over that of a single column, if at all.

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Bransby, Mark Fraser. "Piled foundations adjacent to surcharge loads." Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/251968.

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Fourtounis, Peter D. "Field-test data from soil-structure interaction of shallow and deep foundations." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1587896.

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This thesis presents an analysis of data from two soil-structure interaction field tests, one involving a deep foundation and the other a shallow foundation. The objective of this research is to use the field data to validate and inform models used by engineers. Soil-structure interaction fundamentals and background are first discussed. Field-test data was used in conjunction with a soil-structure system model to develop equations that can be used to determine stiffness and damping of a rigid pile foundation system subjected to forced vibration loading. The stiffness and damping characteristics are presented through complex-valued impedance functions. The equations were applied to field data; however the results were inconclusive due in part to the limited frequency range of the data used. Additionally, soil-foundation interface pressures are analyzed for a shallow foundation system. Analysis of the shallow foundation behavior indicated resonance of the field test structure and the corresponding pressure generation.

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Ahmed, Mahmoud Nasser Hussien. "Effects of Nonlinear Soil-Structure Interaction on Lateral Behavior of Pile Foundations." 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/151949.

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Ng, S. L. D. "Transmission of ground-borne vibration from surface railway trains." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243156.

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Eyce, Bora. "An Investigation Of The Inertial Interaction Of Building Structures On Shallow Foundations With Simplified Soil-structure Interaction Analysis Methods." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610994/index.pdf.

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Seismic response of a structure is influenced by the inertial interaction between structure and deformable medium, on which the structure rests, due to flexibility and energy dissipation capability of the surrounding soil. The inertial interaction analyses can be performed by utilizing simplified soil-structure interaction (SSI) analyses methods. In literature, it is noted that varying soil conditions and foundation types can be modeled by using these SSI approaches with springdashpot couples having certain stiffness and damping. In this study, the seismic response of superstructure obtained by using simplified SSI methods is compared with those of the fixed base systems. For this purpose, single and multi degree of freedom structural systems are modeled with both spring&ndash
dashpot couple and fixed base models. Each system is analyzed for varying structural and soil stiffness conditions under the excitation of three different seismic records. Next, the total base shear acting on the structural system and internal forces of load bearing members are investigated to observe the inertial interaction and foundation uplift effects on the superstructure. It is also aimed to examine the compatibility of the simplified SSI approaches utilized in the analyses. It is concluded that the structural and soil stiffness parameters are the most influential parameters that affect seismic structural response. Structures becomemore sensitive to varying soil properties as the structural stiffness increases. On the other hand, decreasing soil stiffness also increases the sensitivity of the structure to the seismic excitation. Calculated values of total base shear and internal member forces revealed that the inertial interaction might be detrimental for the superstructure. Contrary to general belief, the fixed base approach does not always yield to the results, which are on the safe side. Considering the analysis results, it is concluded that SSI analysis is very useful for more precise and economical design for the seismic behavior.

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Saidin, Fadzilah. "Behavior of geosynthetic reinforced soil walls with poor quality backfills on yielding foundations /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10124.

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Yamamoto, Nobutaka. "Numerical analysis of shallow circular foundations on sands." University of Western Australia. School of Civil and Resource Engineering, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0038.

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This thesis describes a numerical investigation of shallow circular foundations resting on various types of soil, mainly siliceous and calcareous sands. An elasto-plastic constitutive model, namely the MIT-S1 model (Pestana, 1994), which can predict the rate independent behaviour of different types of soils ranging through uncemented sands, silts and clays, is used to simulating the compression, drained triaxial shear and shallow circular foundation responses. It is found that this model provides a reasonable fit to measured behaviour, particularly for highly compressible calcareous sands, because of the superior modelling of the volumetric compression. The features of the MIT-S1 model have been used to investigate the effects of density, stress level (or foundation size), inherent anisotropy and material type on the response of shallow foundations. It was found that the MIT-S1 model is able to distinguish responses on dilatant siliceous and compressible calcareous sands by relatively minor adjustment of the model parameters. Kinematic mechanisms extracted from finite element calculations show different deformation patterns typical for these sands, with a bulb of compressed material and punching shear for calcareous sand, and a classical rupture failure pattern accompanied by surface heave for siliceous sand. Moreover, it was observed that the classical failure pattern transforms gradually to a punching shear failure pattern as the foundation size increases. From this evidence, a dimensional transition between these failure mechanisms can be defined, referred to as the critical size. The critical size is also the limiting foundation size to apply conventional bearing capacity analyses. Alternative approaches are needed, focusing mainly on the soil compressibility, for shallow foundations greater than the critical size. Two approaches, 1-D compression and bearing modulus analyses, have been proposed for those foundation conditions. From the validations, the former is applicable for extremely large foundations, very loose soil conditions and highly compressible calcareous materials, while the latter is suitable for moderate levels of compressibility or foundation size. It is suggested that appropriate assessment of compression features is of great importance for shallow foundation analysis on sand.

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Al-Khazaali, Mohammed. "Soil-Pile, Pile Group Foundations and Pipeline Systems Interaction Behavior Extending Saturated and Unsaturated Soil Mechanics." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38843.

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Rapid growth in population along with positive trends in global economy over the past several decades has significantly contributed to an increased demand for various infrastructure needs worldwide. For this reason, the focus of this thesis has been directed towards extending the mechanics of unsaturated soils, which is an emerging geotechnical engineering field to investigate the behavior of two key infrastructure systems, namely pile foundations and energy pipeline systems. The mechanism of soil-pile foundations and soil-pipeline systems interaction behavior has several similarities. Both these infrastructure facilities require comprehensive understanding of the soil-structure interaction mechanism. Reliable estimation of mechanical properties of both the soil and the soil-structure interface is required for the rational interpretation the load-displacement behavior of pile foundations and pipeline systems. Currently, the design of systems is predominantly based on design codes and guidelines that use empirical procedures or employ the principles of saturated soil mechanics. In many scenarios, pile foundations extend either totally or partly in unsaturated soils as the groundwater table level in many regions is at a greater depth. Such scenarios are commonly encountered in semi-arid and arid regions of the world. In addition, pipeline systems are typically buried at shallow depths in unsaturated soil strata, which are susceptible to wetting and drying, freezing and thawing cycles or both, due to seasonal environmental changes. Capillary stress or matric suction in the unsaturated zone increases the effective stress contribution towards the shear strength and stiffness of soil and soil-structure interface. Extending saturated soil mechanics to design or analyze such structures may lead to erroneous estimation of pile foundation carrying capacity or loads transferred on pipeline body from the surrounding unsaturated soil. Experimental, analytical and numerical investigations were undertaken to study the behavior of single pile, pile group, and pipeline systems in saturated and unsaturated sands under static loading. The experimental program includes 40 single model pile and 2×2 pile group, and six prototype pipeline tests under saturated and unsaturated condition. The results of the experimental studies suggest that matric suction has significant contribution towards the mechanical behavior of both pile foundation and pipeline system. The axial load carrying capacity of single pile and pile group increased approximately 2 to 2.5 times and the settlement reduced significantly compared to saturated condition. The influence of matric suction towards a single pile is significantly different in comparison to pile group behavior. The cumulative influence of matric suction and stress overlap of pile group behavior in sandy soils result in erroneous estimation of pile group capacity, if principles of saturated soil mechanics are extended. Group action plays major role in changing the moisture regime under the pile group leading to incompatible stress state condition in comparison to single pile behavior. On the other hand, the peak axial load on the pipe is almost 2.5 folds greater in unsaturated sand that undergoes much less displacement in comparison to saturated condition. Such an increase in the external axial forces may jeopardize the integrity of energy pipeline systems and requires careful reevaluation of existing design models extending the principles of unsaturated soil mechanics. Two analytical design models to estimate the axial force exerted on pipeline body were proposed. The proposed models take account of matric suction effect and soil dilatancy and provide smooth transition from unsaturated to saturated condition. These models were developed since measurement of the unsaturated soil and interface shear strength and stiffness properties need extensive equipment that require services of trained professional, which are expensive and time consuming. The models utilize the saturated soil shear strength parameters and soil-water characteristic curve (SWCC) to predict the mechanical behavior of the structure in saturated and unsaturated cohesionless soils. The prototype pipeline experimental results were used to verify the proposed models. The predicted axial force on pipeline using the proposed models agrees well with the measured behavior under both saturated and unsaturated conditions. Moreover, numerical techniques were proposed to investigate the behavior of pile foundation and pipeline system in saturated and unsaturated sand. The proposed methodology can be used with different commercially available software programs. Two finite element analysis programs were used in this study; namely, PLAXIS 2D (2012) to simulate soil-pile foundation behavior and SIGMA/W (2012) to simulate soil-pipeline system behavior. The proposed techniques require the information of unsaturated shear strength and stiffness, which can be derived from saturated soil properties and the SWCC. The model was verified using pile and pipeline test results from this study and other research studies from the published literature. There is a good agreement between the measured behavior and the predicted behavior for both the saturated and unsaturated conditions. The methodology was further extended to investigate the behavior of rigid and flexible pipelines buried in Indian Head till (IHT) during nearby soil excavation activity. The simulation results suggest that excavation can be extended safely without excessive deformation to several meters without the need for supporting system under unsaturated condition. The studies summarized in the thesis provide evidence that the principles of saturated soil mechanics underestimate the pile foundations carrying capacity as well as the axial force exerted on pipelines in unsaturated soils. Such approaches lead to both uneconomical pile foundation and unsafe pipeline systems designs. For this reason, the pile and pile group carrying capacity and pipeline axial force should be estimated taking into account the influence of matric suction as well as the dilatancy of the compacted sand. The experimental studies, testing techniques along with the analyses of test results and the proposed analytical and numerical models are useful for better understanding the pile foundation and buried pipeline behaviors under both saturated and unsaturated conditions. The proposed analytical and finite element models are promising for applying the mechanics of unsaturated soils into conventional geotechnical engineering practice using simple methods.

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Varun. "A non-linear dynamic macroelement for soil structure interaction analyses of piles in liquefiable sites." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34718.

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A macroelement is developed for soil-structure interaction analyses of piles in liquefiable soils, which captures efficiently the fundamental mechanisms of saturated granular soil behavior. The mechanical model comprises a nonlinear Winkler-type model that accounts for soil resistance acting along the circumference of the pile, and a coupled viscous damper that simulates changes in radiation damping with increasing material non-linearity. Three-dimensional (3D) finite element (FE) simulations are conducted for a pile in radially homogeneous soil to identify the critical parameters governing the response. The identified parameters, i.e., hydraulic conductivity, loading rate of dynamic loading, dilation angle and liquefaction potential are then expressed in dimensionless form. Next, the macroelement parameters are calibrated as a function of the soil properties and the effective stress. A semi-empirical approach that accounts for the effects of soil-structure interaction on pore pressure generation in the vicinity of pile is used to detect the onset of liquefaction. The predictions are compared with field data obtained using blast induced liquefaction and centrifuge tests and found to be in good agreement. Finally, the macroelement formulation is extended to account for coupling in both lateral directions. FEM simulations indicate that response assuming no coupling between the two horizontal directions for biaxial loading tends to overestimate the soil resistance and fails to capture features like 'apparent negative stiffness', 'strain hardening' and 'rounded corners'.

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Haskell, Jennifer Jane Margaret. "Guidance for the design of pile groups in laterally spreading soil." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648830.

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Kuo, Steven. "Scale Model Shake Table Testing of Shallow Embedded Foundations in Soft Clay." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/839.

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This research involves shake table testing of 1g scale models that mimic the coupled seismic response of a structure on a shallow mat foundation and foundation soil (known as soil-foundation-structural-interaction or SFSI). In previous research, SFSI effects have been quantified through analytical models, numerical analyses, and limited field data. This research works towards increasing the amount of empirical data through scale model shake table testing. A suite of earthquake time histories is considered in evaluating a nominal 10th scale soil-structure model using a flexible wall barrel on a 1-D shake table. San Francisco Young Bay Mud (YBM) is used as the prototype soil and long period narrow building as the prototype structure. Foundation embedment depth, fundamental mode of the structure, and seismic loading function are varied to generate a large database of SFSI results under controlled conditions. The foundation level response is compared to free-field responses to determine the magnitude of the SFSI. The results confirm the effects of foundation embedment on the peak ground motion and the spectral acceleration at the predominant period of the structure. The foundation level accelerations are deamplified compared to free-field results. Results also confirm the legitimacy of the testing platform and program by comparing the data to previous experimental study.

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Varun. "A Simplified Model for Lateral Response of Caisson Foundations." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14016.

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Caisson or pier foundations are encountered as part of the foundation system of tall structures such as bridges, transmission towers, heliostats, etc, and correspond to rigid blocks of length-to-diameter (D/B) ratio on the order of D/B = 2-6. As a result of their geometry and stiffness characteristics, the mechanisms of load transfer from the superstructure to the surrounding soil and their kinematic response to seismic wave propagation are governed by a complex stress distribution at the pier-soil interface, which cannot be adequately represented by means of simplified Winkler models for shallow foundations or flexible piles. Continuum model solutions, such as 3D finite elements (FE) cannot be employed frequently in practice for the design of non-critical facilities due to the cost and effort associated with these analyses. The objective of this work is to develop a Winkler-type model for the analysis of transversely-loaded caissons, which approximately accounts for all the main soil resistance mechanisms mobilized, while retaining the advantages of simplified methodologies for design at intermediate levels of target accuracy. Investigation of the governing load-transfer mechanisms and development of complex spring functions is formulated on the basis of 3D FE simulations. Initially, the soil-structure stiffness matrix is computed by subjecting the pier to transverse static and dynamic loading at the top, and numerically estimating the response. Complex frequency-dependent functions are next developed for the spring constants by equating the stiffness matrix terms to the analytical expressions developed for the four-spring model. Sensitivity analyses are conducted for optimization of the truncated numerical domain size, finite element size and far-field dynamic boundary conditions to avoid spurious wave reflections. Simulations are next conducted to evaluate the transient response of the foundation subjected to vertically propagating shear waves, and results are compared to the response predicted by means of the 4-spring model. Finally, the applicability of the method is assessed for soil profiles with depth-varying properties. While the methodology developed is applicable for linear elastic media with no material damping, the expressions of complex spring functions may be extended to include hysteretic damping, nonlinear soil behavior and soil-foundation interface separation, as shown in the conclusions.

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Hossain, Muhammad Shazzad. "New mechanism-based design approaches for spudcan foundations in clay." University of Western Australia. School of Civil and Resource Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0103.

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[Truncated abstract] Three-legged mobile jack-up rigs supported on spudcan foundations are used to perform most offshore drilling in shallow to moderate water depths, and are now capable of operating in water depths up to 130 m. With the gradual move towards heavier rigs in deeper water, and continuing high accident rates during preloading of the spudcan foundations, appraisal of the performance and safety of jack-up rigs has become increasingly important. A crucial aspect of this is to improve understanding of the mechanisms of soil flow around spudcan foundations undergoing continuous large penetration, and to provide accurate estimates of spudcan penetration resistance, avoiding excessive conservatism. Spudcan foundations undergo progressive penetration during preloading, contrasting with onshore practice where a footing is placed at the base of a pre-excavated hole or trench. However, spudcan penetration is generally assessed within the framework used for onshore foundations, considering the bearing resistance of spudcans pre-placed at different depths within the soil profile. The lack of accurate design approaches that take proper account of the nature of spudcan continuous penetration, which is particularly important in layered soil profiles, is an important factor in the high rate of accidents. ... It was found that when a spudcan penetrated into single layer clay, there were three distinct penetration mechanisms: during initial penetration, soil flow extended upwards to the surface leading to surface heave and formation of a cavity above the spudcan; with further penetration, soil began to flow back gradually onto the top of the spudcan; during deep penetration, soil back-flow continued to occur while the initial cavity remained unchanged. For spudcan penetration in stiff-over-soft clay, four interesting aspects of the soil flow mechanisms were identified: (a) vertically downward motion of the soil and consequent deformation of the layer interface; (b) trapping of the stronger material beneath the spudcan, with this material being carried down into the underlying soft layer; (c) delayed back-flow of soil around the spudcan into the cavity formed above the spudcan; (d) eventual localised flow around the embedded spudcan, surrounded by strong soil. At some stage during continuous spudcan penetration, the soil starts to flow back into the cavity above the spudcan. The resulting back-flow provides a seal above the penetrating spudcan and limits the cavity depth. It was shown that the current offshore design guidelines are based on the wrong criterion for when back-flow occurs. New design charts with robust expressions were developed to estimate the point of back-flow and hence the cavity depth above the installed spudcan. Load-penetration responses were presented in terms of normalised soil properties and geometry factors for both single layer and two-layer clay profiles, taking full account of the observed flow mechanisms. Further, guidelines were suggested to evaluate the likelihood and severity of spudcan punch-through failure in layered clays. Finally, the effect of strain-rate and strain-softening was examined, in an attempt to model real soil behaviour more closely. Adjustment factors were proposed to modify the design approaches developed on the basis of ideal elastic-perfectly plastic soil behaviour.

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Yuksekol, Umit Taner. "A Simple Assessment Of Lateral Pier Response Of Standard Highway Bridges On Pile Foundations." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608135/index.pdf.

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Group of piles are widely used deep foundation systems to resist lateral and vertical loads. Seismic and static performance of pile groups mostly depend on soil type, pile spacing and pier rigidity. Not many pile lateral load tests have been performed due to high costs. Advanced and complex analytical methods were developed over the years to assess nonlinear lateral pile response. This research is conducted aiming at developing a practical analysis method to verify the lateral performance of pile groups and its effect on overall response of bridge utilizing the available pile lateral load test data. Empirical constants derived from evaluation of lateral load tests are used in a simple formulation to define the nonlinear behavior of the pile-soil system. An analysis guideline is established to model the nonlinear soil-bridge interaction by the help of a general purpose structural analysis program comprising recommendations for various cases. Results of the proposed method is compared to the results of industry accepted advanced methods using response spectrum and nonlinear time history analyses to assess the suitability of this new application. According to the analysis results, proposed simple method can be used as an effective analysis tool for the determination of response of the superstructure.

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Pinna, Rodney. "Buckling of suction caissons during installation." University of Western Australia. School of Civil Engineering, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0008.

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Suction caissons are a foundation system for offshore structures which offer a number of advantages over traditional piled foundations. In particular, due to the method of installation used, they are well suited for deep-water applications. The suction caisson consists of an open ended cylindrical shell, which is installed below the seabed in a sequence which consists of two loading phases. The caisson is first installed part way under self weight, with the installation being completed by lowering the pressure within the cylinder and thus allowing the ambient water pressure to force the caisson into the ground. This thesis examines a number of structural issues which result from the form of the caisson — essentially a thin walled cylinder — and the interaction of the caisson with the surrounding soil during installation. To do this, variational analysis and nonlinear finite element analysis are employed to examine the buckling and collapse behaviour of these cylinders. In particular, two issues are considered; the influence of the open end, and the interaction between the cylinder and soil on the buckling and collapse loads. First, the behaviour of open ended cylinders is considered, where the boundary condition at the open end is allowed to vary continuously from completely free to pinned, by the use of a variable lateral spring. This lateral spring restraint may be considered to represent the intermediate restraint provided by a ring stiffener which is not fully effective. The effect of various combinations of boundary conditions is accounted for by the use of a multiplier on the lower bound to the buckling load of a cylinder with classical supports. The variable spring at the open end may also be considered to be an initial, simple representation of the effect of soil restraint on the buckling load. More complex representations of the soil restraint are also considered. A nondimensional factor is proposed to account for the influence of this spring on the buckling load. One combination of boundary conditions, where the upper end of the caisson is pinned, and the lower end free (referred to as a PF boundary condition), is found to have buckling and collapse behaviour which is unusual for cylindrical shells. Buckling loads for such shells are much lower than would be found for cylinders with more typical boundary conditions, and of similar dimensions. More unusually however, PF cylinders are shown to have positive postbuckling strength. The behaviour is found to be a result of the large flexibility which results from the low restraint provided by the PF boundary conditions. This is shown by continuously decreasing the flexibility of the cylinder, by increasing the axial restraint at the pinned end. It is shown that this results in a large increase in buckling load, and a return to more usual levels of imperfection sensitivity. In particular, with an intermediate level of axial restraint, buckling loads and imperfection sensitivity are intermediate between those of PF shells with no, and with full, axial restraint. Overall however, collapse loads for PF cylinders with no additional restraint are well below those of cylinders with stiffer boundary conditions, for equal geometries. Eigenvalue buckling of cylinders fully and partially embedded in an elastic material are examined, and two analytical solutions are proposed. One of these is an extension of a method previously proposed by Seide (1962), for core filled cylinders, to pin ended cylinders which have support from both a core and a surrounding material. The second method represents the elastic support as a two parameter foundation. While more approximate than the first method, this method allows for the examination of a wider range of boundary conditions, and of partial embedment. It is found that the buckling load of the shell/soil system decreases as the embedment ratio decreases. Collapse of fully and partially embedded cylinders is also examined, using nonlinear finite element analysis. The influence of plasticity in the soil is also considered. For cylinders with small imperfections, it is found that the collapse load shows a large increase over that of the same cylinder with no soil support. However, as the size of initial geometric imperfections increases, it is found that the collapse load rapidly approaches that of the unsupported cylinder. In particular, in weak soils the gain in strength over the unsupported shell may be minimal. The exception to this is again PF cylinders. As these have relatively low collapse loads, even very weak soils are able to offer an increase in collapse load over the unsupported case. Finally, a summary of these results is provided in the form of guidance for design of such structures.

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20

Unutmaz, Berna. "Assessment Of Soil." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610285/index.pdf.

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Although there exist some consensus regarding seismic soil liquefaction assessment of free field soil sites, estimating the liquefaction triggering potential beneath building foundations still stays as a controversial and difficult issue. Assessing liquefaction triggering potential under building foundations requires the estimation of cyclic and static stress state of the soil medium. For the purpose of assessing the effects of the presence of a structure three-dimensional, finite difference-based total stress analyses were performed for generic soil, structure and earthquake combinations. A simplified procedure was proposed which would produce unbiased estimates of the representative and maximum soil-structure-earthquake-induced iv cyclic stress ratio (CSRSSEI) values, eliminating the need to perform 3-D dynamic response assessment of soil and structure systems for conventional projects. Consistent with the available literature, the descriptive (input) parameters of the proposed model were selected as soil-to-structure stiffness ratio, spectral acceleration ratio (SA/PGA) and aspect ratio of the building. The model coefficients were estimated through maximum likelihood methodology which was used to produce an unbiased match with the predictions of 3-D analyses and proposed simplified procedure. Although a satisfactory fit was achieved among the CSR estimations by numerical seismic response analysis results and the proposed simplified procedure, validation of the proposed simplified procedure further with available laboratory shaking table and centrifuge tests and well-documented field case histories was preferred. The proposed simplified procedure was shown to capture almost all of the behavioral trends and most of the amplitudes. As the concluding remark, contrary to general conclusions of Rollins and Seed (1990), and partially consistent with the observations of Finn and Yodengrakumar (1987), Liu and Dobry (1997) and Mylonakis and Gazetas, (2000), it is proven that soil-structure interaction does not always beneficially affect the liquefaction triggering potential of foundation soils and the proposed simplified model conveniently captures when it is critical.

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21

Glatz, Thomas. "The electro-osmotic acceleration of infiltration into the subgrade of pavements." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16326.

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Thesis (MScIng)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: The moisture content of road foundations plays an important role in the durability of the pavement and the driving comfort of the road. After a pavement has been completed, gradual moisture changes occur in the foundations until equilibrium conditions can be reached, and this can have negative results if expansive clays, for example, are present in the foundation. Pre-wetting of the foundation material is seen as a method to minimilize moisture changes after construction, but if the pavement was already completed, it would be very difficult to change or alter the moisture content in the foundation, because water could then only be applied to the shoulder areas of the road and horizontal infiltration in the soil is exceptionally slow. The research which is reported in this account was undertaken to determine whether the process of electro-osmosis could be applied to accelerate water infiltration underneath covered areas, as in, for example, road foundation layers. Electro-osmosis, if found to be successful, has various advantages, of which the most important is that it can be applied without stopping the normal operations of the road. This research was carried out on a mixture of G5 material (TRH14 classification) and fine material in the form of clay with a low plasticity. Firstly, tests were performed to determine the percentage of fines required. It was found that, if too little fines were present infiltration did not occur, because moisture could flow freely through the openings between the rough aggregate. Electro-osmosis also had no effect on the rate of flow. The allocated amount of fines required to fill sufficient openings was about 30% (TRH14 classification of mixture is G10). Free flow was stopped and true infiltration occurred. Simultaneously, the rate of infiltration could be accelerated with electro-osmosis. Furthermore, a two-dimensional model of a road was constructed with electrodes placed on both sides, with the aim to determine the infiltration pattern controlled by electro-osmosis and what the effect of the initial moisture content would be on the process. Water was introduced to the one side of the model road and the wetting of the foundation was investigated. If the electric current for electro-osmosis was switched off, the infiltration was mainly vertical, as expected, but with the current switched on, there was an obvious acceleration of infiltration in the horizontal direction. As in the case of the initial tests, it was found that electro-osmosis was not very successful to accelerate horizontal infiltration at low percentages of fines. Furthermore, it was obvious that electroosmosis was also more effective if the initial moisture content of the soil was low. Low amounts of fines and high initial moisture contents had rather the electroosmotic flow of water passing underneath the road as a result instead of infiltration acceleration, with the result that the moisture content did not change much. The research thus showed that electro-osmosis is a possible manner in which moisture could be conducted into the foundation layers of roads to increase the moisture content if the appropriate amount of fines and moisture content were present in the foundation material. Further research could still be carried out and the materials in each case should be practically evaluated before this method could be continued with.
AFRIKAANSE OPSOMMING: Die voginhoud van padfondamente speel ’n belangrike rol in die duursaamheid van die plaveisel en die rygerief van die pad. Nadat ’n plaveisel voltooi is, vind daar geleidelike vogverandering in die fondamente plaas totdat ewewigstoestande bereik is, en dit kan nadelige gevolge inhou indien uitsettende kleie byvoorbeeld in die fundament teenwoordig is. Voorafbenatting van die fondamentmateriaal word gereken as ’n metode om vogveranderinge na konstruksie te minimeer, maar indien die plaveisel reeds voltooi is, is dit baie moeilik om die voginhoud in die fondament te verander of beheer omdat water dan slegs buite die skouerareas van die pad toegedien kan word en horisontale infiltrasie in grond uiters stadig is. Die navorsing waaroor hierin verslag gedoen word, is onderneem om te bepaal of die proses van elektro-osmose aangewend kan word om waterinfiltrasie onder bedekte areas, soos byvoorbeeld padfondamentlae, te versnel. Elektro-osmose, indien dit suksesvol blyk te wees, hou verskeie voordele in, waarvan die belangrikste dat dit aangewend kan word sonder om die normale bedryf van die pad te staak. Die ondersoek is uitgevoer op ’n mengsel van G5 materiaal (TRH14 klassifikasie) en fynstof in die vorm van klei met ’n lae plastisiteit. Eerstens is toetse uitgevoer om die persentasie fynstof wat nodig is, te bepaal. Daar is bevind dat, indien te min fynstof teenwoordig is, infiltrasie nie plaasvind nie aangesien water vryelik deur die openinge tussen die growwe aggregaat kan vloei. Elektro-osmose het ook geen effek op die vloeitempo gehad nie. Die aangewese hoeveelheid fynstof om genoegsame openinge te vul was ongeveer 30% (TRH14 klassifikasie van mengsel is G10). Vrye vloei is dan gestuit en ware infiltrasie het plaasgevind. Terselfdertyd kon die tempo van infiltrasie versnel word met elektro-osmose. Voorts is ’n twee-dimensionele model van ’n pad gebou, met elektrodes aan weerskante geplaas, met die doel om te bepaal of die infiltrasiepatroon deur elektro-osmose beheer kon word en wat die effek van beginvoginhoud op die proses sal wees. Water is aan een kant van die modelpad ingevoer en die benatting van die fondament bestudeer. Indien die elektriese stroom vir elektroosmose afgeskakel was, was die infiltrasie hoofsaaklik vertikaal, soos verwag, maar met die stroom aangeskakel was daar duidelike versnelling van infiltrasie in die horisontale rigting. Net soos in die geval van die aanvanklike toetse is bevind dat elektro-osmose nie baie suksesvol was om horisontale infiltrasie te versnel by lae persentasies fynstof nie. Dit het verder geblyk dat elektro-osmose ook meer effektief was indien die aanvanklike voginhoud van die grond laag was. Lae hoeveelhede fynstof en hoë aanvanklike voginhoude het eerder elektroosmotiese deurvloei van water onderdeur die pad tot gevolg gehad as infiltrasieversnelling, met die gevolg dat die voginhoud nie veel verander het nie. Die navorsing het dus getoon dat elektro-osmose ’n moontlike wyse is waarop water in die fondamentlae van paaie ingevoer kan word om die voginhoud te verhoog indien die geskikte hoeveelheid fynstof en voginhoud in die fondamentmateriaal teenwoordig is. Verdere navorsing kan nog uitgevoer word en die materiale van elke geval sal prakties evalueer moet word voordat met die metode voortgegaan kan word.

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22

Mendonça, Jocélio Cabral. "Um modelo computacional de análise da interação estrutura-maciço de solos em edifícios." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-05122017-085404/.

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Uma solução computacional geral e expansível de análise da interação estrutura-maciço de solos foi desenvolvida adotando metodologia orientada a objetos. A técnica computacional apresenta um menu de retaguarda que torna a manipulação dos dados de entrada e os processos computacionais mais criteriosos e seguros. Os materiais possuem comportamento perfeitamente elástico-linear, enquanto o mecanismo de transferência de carga estrutura-solo é não linear. O maciço de solos é modelado através de dados de sondagens SPT e mapeamento geotécnico. A fundação é discretizada verticalmente para se obter as matrizes de flexibilidade da estrutura de fundação (MFEF) e do maciço de solos (MFMS). O processo interativo básico consiste em obter o vetor de recalques nos apoios pelo produto do vetor de cargas verticais com as matrizes MFEF e MFMS. Na seqüência, calcula-se o vetor de redistribuição de cargas pelo produto do vetor de recalques com a matriz de rigidez da superestrutura (MRS). Um procedimento iterativo condiciona a convergência de recalques e cargas verticais nos apoios. A solução foi utilizada para analisar o comportamento de edifícios de diferentes geometrias em planta e espacial, variando o perfil geotécnico do maciço suporte e a técnica de execução da estrutura de fundação.
A general and expansible computational code based in the oriented to object programming technique was developed aiming the soil-structure interaction analysis. This computational technique has a special feature that makes the data input operations and the computer processing safer and more criterious. This model considers that all materials behaves as perfectly linear elastic materials, although the soilstructure transfer mechanism is of non-linear nature. The soil mass compressibility and resistance are modelled from soil data obtained from geotechnical mapping techniques and SPT boreholes data. The flexibility matrix (MFEF) of the structural foundation elements and the flexibility matrix (MFMS) of soil mass elements are obtained through a numerical discretization procedure. The basic interative process consists in the calculation of the supports displacement vectors obtained by the multiplication of the vertical load vector by the MFEF and the MFMS matrix. Finally, the load redistribution is obtained by the multiplication of the displacement vector by the structural rigidity matrix (MRS). The uniqueness of the solution is guaranteed by the convergence of the displacements and vertical supports reactions by using an iterative procedure. This computational code was applied to the analysis of the behaviour of spatial framed buildings with varied geometry, taking into account different geotechnical soil conditions and different types of foundations.

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23

Utkutug, Deniz. "A Parametric Study Investigating The Inertial Soil-structure Interaction Effects On Global And Local Deformation Demands Of Multistory Steel Mrf Structures Resting On Surface Rigid Mat Foundations." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610490/index.pdf.

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In reality, dynamic response of a structure supported on a compliant soil may vary significantly from the response of same structure when supported on a rigid base. A parametric study is conducted for the analysis of the variation in the global and the local deformation demands caused by the inertial soil-structure interaction effects. For the purposes of the study, nonlinear dynamic analyses are performed on 7 steel moment-resisting frame models, which are prepared by the virtue of fixed-base and flexible-base (interacting) conditions. Foundation is modeled with the Truncated Cone Model (Wolf, 1994) with the frequency independent coefficients. Free-field earthquake acceleration records are selected to conform to NEHRP equivalent Site Classes C and D. The study is limited to the structures founded on surface rigid mat foundations subjected to vertically propagating horizontally polarized coherent shear waves. Statistical analysis based on multiple linear regression procedure is performed to represent the variation in the response. Within the scope of the study, the wave parameter and the aspect ratio are observed to be directly proportional to the variation in the response, as a general trend. Maximum beneficial contribution of the SSI is found to be 6% in both global and local deformation demands. In addition, the contribution of inertial interaction effects is found to be in a decreasing trend for the increasing levels of ductility demands. Finally, upper limits of wave parameter for H/R=0.5, 1, 2 and 3 are calculated where the variation in the demands are capped at 1.0.

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24

Lee, Kok Kuen. "Investigation of potential spudcan punch-through failure on sand overlying clay soils." University of Western Australia. School of Civil and Resource Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0212.

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When a jack-up foundation is installed on seabeds consisting of a sand layer overlying soft clay, potential for 'punch-through' failure exists. This happens due to an abrupt reduction in bearing resistance when the foundation punches a block of sand into the underlying soft clay in an uncontrolled manner. This can lead to a sudden large penetration that can cause temporary decommissioning and even toppling of the unit. This research has addressed this problem with the aim of developing a practical design method for the jack-up industry to assess potential punch-through hazards. This objective has been achieved with the successful development of a new conceptual model for predicting the peak penetration resistance and a consistent method for constructing a complete resistance profile of spudcan foundations penetrating through sand into the underlying clay. The analytical basis of the new conceptual model follows the approach for silo analysis, and takes into account the stress level and dilatant response of sand. It is therefore a significant improvement over the punching shear and load spread models recommended in the current industry guidelines SNAME (2002), which do not consider the strength properties of the sand. To provide relevant experimental data for the new model, an extensive series of 30 continuous penetration tests were performed using the UWA drum centrifuge. These experimental results were retrospectively simulated using finite element (FE) analysis, in order to back-calculate the stress-level dependent friction and dilation angles in the sand during peak penetration resistance. The back-analysis showed that larger values of peak resistance gave lower friction and dilation angles, which is consistent with gradual suppression of dilatancy under high confining stress. When compared to published results from visualisation experiments, the FE analysis showed a similar failure mechanism during peak resistance, where a frustum of sand was forced into the underlying clay, with the outer angle reflecting the dilation in the sand. This has formed the basis of the new conceptual model. The performance of the new model in predicting the experimental peak resistance was compared with other existing analytical methods. Additional experimental results, including those already in the literature, were incorporated in the comparative study. It was found that the new conceptual model generally gave a good prediction of the experimental values, while the prediction from SNAME (2002) was conservative, with the predicted values being about half the experimental results on average. It was also shown that the new model could be modified to predict the post-peak penetration resistance in the sand layer. Finally, an analytical method for predicting the resistance profiles in the underlying clay was devised based on new bearing capacity factors developed through FE analysis. By joining the values of peak resistance, post-peak resistance and the resistance profile in the underlying clay, a complete simplified penetration resistance profile for spudcan foundations in sand overlying clay can be generated. The predicted profiles were shown to match the experimental results well.

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Thomazo, Luiz Henrique. "Formulação do metodo dos elementos de contorno indireto para resposta transiente em meios visco-elasticos 2D." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263977.

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Orientadores: Euclides de Mesquita Neto, Edson Antonio Capello Sousa
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-09T04:23:51Z (GMT). No. of bitstreams: 1 Thomazo_LuizHenrique_M.pdf: 1773463 bytes, checksum: e38435e9b18935ddc2edc19b8b2efac4 (MD5) Previous issue date: 2004
Resumo: Este trabalho apresenta uma metodologia para a realização de análises dinâmicas estacionárias e transientes em domínios visco-elásticos limitados ou ilimitados, utilizando-se o Método dos Elementos de Contorno. São utilizados como estados auxiliares soluções não-singulares de problemas do semi-espaço e do espaço completo de meios visco-elásticos. Os estados visco-elásticos auxiliares são sintetizados numericamente, tanto no domínio da freqüência, como no domínio do tempo. Os mencionados estados auxiliares são constituídos das soluções em tensão e deslocamento resultantes de cargas espacialmente constantes, aplicadas sob segmentos lineares tanto na superfície de semi-espaços, como no interior de espaços completos. Inicialmente os estados auxiliares são sintetizados numericamente no domínio da freqüência, dando origem à análise de problemas estacionários. Na seqüência estados auxiliares transientes são obtidos a partir da aplicação da transformada de Fourier rápida (FFT) sobre os estados estacionários mencionados. Os estados auxiliares são utilizados para a síntese de uma versão não singular Indireta do MEC (MEC-I) tanto no domínio da freqüência quanto no domínio do tempo. No trabalho ainda é formulada e implementada a inclusão de um corpo rígido interagindo com o meio discretizado pelo MEC-I. O comportamento visco-elástico do contínuo é introduzido pelo princípio da correspondência e são analisados os modelos de histerése constante e de Kelvin-Voigt
Abstract: The main purpose of the present work is to further develop a methodology to perform stationary and transient dynamic analysis of viscoelastic continua by the Boundary Element Method. Numerically synthetized stationary and transient, half-space and full-space auxiliary states are employed to render a non-singular implementation of the indirect version of the Boundary Element Method, IBEM. The auxiliary states used in this word are displacement and traction components stemming from the solution two stress bounary value problems. A constant traction distribution applied at a linear segment over the viscoelastic half-space surface and at the interior of the viscoelastic full-space describe the solutions applied to formulate the BEM. The IBEM is formulated and implemented to render the dynamic solution of bounded and unbounded domains. The interaction of the IBEM mesh with a massless rigid body is also formulated in the context of this work. Viscoelastic effects are included by means of the correspondence principle. The influence of the constant hysteresis and the Kelvin-Voigt damping models are studied.
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica

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26

Jordão, Darcília Ruani. "Estabilidade global de edifícios sobre fundações profundas, considerando a interação estrutura-solo." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-23042008-100421/.

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Apresenta-se uma metodologia para análise de interação solo-estrutura aplicada ao estudo da estabilidade global de estruturas de concreto armado sobre fundações profundas. A metodologia de análise de interação solo-estrutura consiste num processo iterativo no qual, inicialmente, determinam-se as reações da superestrutura, considerando os apoios indeslocáveis. Com estas reações, por meio do programa EDRR, calculam-se os deslocamentos dos blocos de fundação. Com as reações e estes deslocamentos calcula-se os coeficientes das molas que substituirão os apoios fixos da superestrutura, cujas reações são recalculadas. Repete-se o processo até que as reações de duas iterações consecutivas sejam aproximadamente iguais. O programa EDRR (estaqueamento, deslocamento horizontal, recalque, rotação), elaborado em linguagem FORTRAN, determina os esforços no estaqueamento através de análise matricial considerando a reação horizontal do solo. Os deslocamentos horizontais e rotações são calculados através da teoria de viga sobre apoio elástico, enquanto os recalques no maciço de solos são calculados considerando o efeito de grupo através da continuidade do meio. Através de exemplos de casos reais, com medida de recalques, demonstra-se a eficiência da metodologia na previsão dos recalques. Além disso, procura-se mostrar que os recalques influenciam na estabilidade global da superestrutura.
This work presents a methodology for the analysis of soil-structure interaction applied to the study of the global stability of reinforced concrete structures on deep foundations. The soil-structure interaction methodology consists of an iterative process in which, at the beginning, the superstructure support reactions are computed, assuming fixed supports. Using the computed reactions, with aid of the EDRR program, foundation cap displacements are computed. Then, with the computed support reactions and displacements, spring coefficients, which will replace the fixed supports, are calculated. The process is repeated until reactions determined in two consecutive iterations are close to each other. The EDRR program, written in FORTRAN language, computes the forces at the top of piles by means of matrix analysis, taking into account the horizontal soil reaction. Horizontal linear displacements and rotations are computed using the elastic foundation beam theory, and soil mass settlements are computed taking into account the group effect considering the mass continuity. Thro ugh real case examples, with settlement monitoring, the proposed methodology efficiency is demonstrated. Furthermore, the influence of settlements on the structure global stability is shown.

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Antoniazzi, Juliana Pippi. "INTERAÇÃO SOLO-ESTRUTURA DE EDIFÍCIOS COM FUNDAÇÕES SUPERFICIAIS." Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/7763.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This work deals with the consideration of Soil-Structure Interaction (SSI) in structural design of reinforced concrete buildings on shallow foundations of the isolated footing type. It carried out a comprehensive review on the major works done in the area and the methods for obtaining parameters and variables involved in the analysis. Numerical examples were developed with the aim of identifying internal forces and displacements changes caused by considering the deformation of soil and the construction sequence in the structural analysis. The examples also intended to show data and procedures for the required calculations in the consideration of the SSI in structural designs. Among the computational tools used in the numerical examples is ESPACIAL_ISE program - a program developed in FORTRAN by Alva (2010). This program employs the method of Aoki and Lopes (1975), which uses the equations of Mindlin (1936) for calculating the settlements, together with the Steinbrenner´s method (1934) to consider the stratigraphy of the soil mass. It was also used in the numerical examples SISEs computer system (System of Soil-Structure Interaction) - developed by TQS Informatics - which allows that the entire structure and foundation are represented in a single structural model. The results of this study showed the importance of considering the soil deformation, although in a simplified form, replacing the fixed support hypothesis in structural designs. Thus, for a more realistic structural analysis of multistory buildings, it is recommended that the soil-structure interaction is considered together with the construction sequence.
O presente trabalho trata da consideração da Interação Solo-Estrutura (ISE) em projetos estruturais de edifícios em concreto armado sobre fundações superficiais do tipo sapatas isoladas. É realizada uma ampla revisão bibliográfica sobre os principais trabalhos desenvolvidos na área e sobre os métodos para a obtenção de parâmetros e variáveis envolvidos na análise. Exemplos numéricos foram desenvolvidos com o intuito de identificar as alterações de esforços e deslocamentos ocasionadas ao se considerar a deformabilidade do solo e a sequência construtiva na análise estrutural. Os exemplos também tiveram como objetivo mostrar os dados e os procedimentos de cálculo necessários para a consideração da ISE em projetos estruturais. Entre as ferramentas computacionais utilizadas nos exemplos numéricos está o programa ESPACIAL_ISE - programa desenvolvido em linguagem FORTRAN por Alva (2010). O referido programa emprega o método de Aoki e Lopes (1975), o qual utiliza as equações de Mindlin (1936) para o cálculo dos recalques, em conjunto com o procedimento de Steinbrenner (1934) para considerar a estratigrafia do maciço de solos. Também foi utilizado nos exemplos numéricos o sistema computacional SISEs (Sistema de Interação Solo-Estrutura) desenvolvido pela TQS Informática - o qual permite que toda a estrutura e a fundação sejam representadas em um modelo estrutural único. Os resultados obtidos neste trabalho mostraram a importância da consideração da deformabilidade do solo, ainda que de forma simplificada, em substituição à hipótese de apoios indeslocáveis nos projetos estruturais. Para uma análise estrutural mais realista em edifícios de múltiplos andares, recomenda-se que a interação solo-estrutura seja considerada juntamente com a sequência construtiva.

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Leidwanger, Cathy. "Etude des tassements différés à partir de résultats d'essais au diflupress longue durée." Grenoble 1, 1993. http://www.theses.fr/1993GRE10153.

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L'observation des tassements differes de batiments lourds a montre la difficulte d'obtenir une bonne prevision des tassements a long terme a partir des seuls essais de laboratoire. E. D. F. A alors developpe un appareil de mesure in situ du comportement differe des sols sous chargement constant, le diflupress l. D. L'analyse des essais au diflupress conduit a la definition d'une pente de fluage. Cette derniere peut etre liee a la contrainte appliquee au sol par la sonde par des relations analogues a celles utilisees pour l'exploitation des essais de fluage en laboratoire. En adaptant les formulations classiques de calcul previsionnel de tassement, on obtient les tassements differes a partir de la caracteristique mesuree au diflupress. L'etude fine de l'ensemble des batiments de deux sites nucleaires fournit une relation entre la deformation differee de la couche compressible et la contrainte induite dans le sol sous chaque batiment. Cette deformation peut etre liee a la caracteristique mesuree au diflupress: on obtient alors une methode simple de prevision du tassement. On utilise egalement les resultats des essais au diflupress l. D. Afin d'identifier les parametres elastoviscoplastiques du modele de comportement de dafalias-kaliakin. On utilise cette loi dans le code aux elements finis lagamine, seule ou couplee avec une loi d'ecoulement qui permet de tenir compte de la presence d'eau interstitielle. On modelise ensuite le tassement differe des centrales nucleaires avec les parametres identifies a partir de l'essai au diflupress: on obtient une pente de tassement differe proche de celle observee sur le site. Une etude fine des chemins de contraintes suivis sous l'ensemble de la fondation, conduit a une approximation possible pour le chemin suivi. On constate egalement que la partie visqueuse du modele est active essentiellement sous la fondation. Cela aboutit a l'elaboration d'une methode simplifiee a partir de la reduction unidimensionnelle de la loi de dafalias-kaliakin

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Labaki, Josué 1982. "Vibration of flexible and rigid plates on transversely isotropic layered media = Vibração de placas flexíveis e rígidas em meios estratificados transversalmente isotrópicos." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263957.

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Orientador: Euclides de Mesquita Neto
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-21T04:39:32Z (GMT). No. of bitstreams: 1 Labaki_Josue_D.pdf: 3777054 bytes, checksum: 98096129397b78d6f60e69e7d8210b9b (MD5) Previous issue date: 2012
Resumo: Este trabalho apresenta novos modelos para descrever o comportamento harmônico de placas rígidas e flexíveis incrustadas em meios estratificados. Incrustações profundas das placas são representadas por interfaces bi-materiais de meios viscoelásticos transversalmente isotrópicos. Incrustações rasas são representadas por meios estratificados viscoelásticos transversalmente isotrópicos. Os modelos de meios circundantes são obtidos com base em modelos clássicos disponíveis na literatura, que estão em coordenadas cilíndricas. O método usado para obter esses modelos envolve transformadas de Hankel, com o objetivo de obter as equações de movimento em um domínio no qual elas possam ser manipuladas algebricamente. Algumas funções de interesse são expandidas em séries de Fourier, para decompor grandezas como deslocamentos, tensões e carregamentos em termos axissimétricos e antissimétricos. No modelo de placa rígida, a incrustação da placa é descrita assumindo que uma superfície circular do meio circundante é rígida. Um conjunto de equações integrais acopladas, que relaciona deslocamentos e força de superfície atuantes nesta superfície, é resolvido por meio de discretização da superfície em discos anulares concêntricos. A teoria de Kirchhoff para placas finas é usada como modelo de placa flexível. Uma tentativa de solução para o perfil de deflexão da placa é definido em termos de série de potência. Uma função envolvendo as energias de deformação da placa e do meio é definida, cuja minimização, sob as restrições impostas pelas condições de contorno da placa, resulta no perfil de deflexão da placa incrustada. Os modelos de placa rígida e flexível incrustadas são comparados com resultados da literatura para incrustações em meios isotrópicos. Novos resultados são fornecidos para os casos de incrustações rasas ou profundas em meios viscoelásticos estratificados transversalmente isotrópicos, sob a ação de forças harmônicas verticais e transversais, assim como momentos. Os resultados deste trabalho contribuem para o estudo de fundações e âncoras em solos estratificados
Abstract: This work presents new models to describe the time-harmonic behavior of rigid and flexible circular plates embedded in layered media. Deep embedments of the plates are represented by bimaterial viscoelastic transversely isotropic interfaces. Shallow embedments are represented by multilayered viscoelastic transversely isotropic media. The models of surrounding media are derived according to classical models available in the literature, which are in cylindrical coordinates. The method used to derive these models involves Hankel transforms, in order to bring the equations of motion to a domain in which they can be dealt with algebraically. A few functions of interest are expanded in Fourier series, in order to describe quantities such as displacements, stresses and loadings in terms of axisymmetric or antisymmetric components. In the model of rigid plate, the embedded plate is described by considering that a circular surface within the surrounding medium is rigid. A set of coupled integral equations, which relate the displacements and the unknown tractions across this surface, is solved by discretizing the surface into concentric annular disc elements. Kirchhoff theory of thin elastic plates is used to describe the flexible plate. A trial function to describe the deflection profile of the plate is defined in terms of a power series. An energy functional is established, which involves the strain energy of the plate and of its surrounding medium. The minimization of this functional, under the restriction that is must satisfy the boundary conditions at the plate edge, results in the deflection profile of the embedded plate. The models of embedded plates are compared with previous results from the literature for the case of different embedments in isotropic media. New research results are provided for the case of shallow and deep embedments in layered viscoelastic transversely isotropic media, under time-harmonic vertical and transverse loads and rocking moments. The results of this work contribute to the study of embedded foundations and anchors in layered soil
Doutorado
Mecanica dos Sólidos e Projeto Mecanico
Doutor em Engenharia Mecânica

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Júnior, Osvaldo Gomes de Holanda. "Interação solo-estrutura para edifícios de concreto armado sobre fundações diretas." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-21122017-114906/.

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Interação solo-estrutura é o objeto de estudo deste trabalho. O principal objetivo é verificar a verdadeira importância desse fenômeno na análise estrutural de edifícios usuais em concreto armado sobre fundações diretas. Inicialmente apresenta-se um estudo sobre o comportamento do solo. Logo após são descritos os processos de dimensionamento de fundações superficiais, com base na NBR 6122 (1996). Descrevem-se em seguida os elementos barra e sapata rígida, utilizados na modelagem do sistema superestrutura-subestrutura-maciço de solos. Discute-se a modificação do elemento sapata rígida, que representa fundação e solo, para a consideração de uma camada indeslocável no interior do solo. De acordo com a teoria apresentada, dois exemplos são submetidos a duas análises, com ou sem a consideração da interação sol-estrutura, para que os resultados sejam comparados. Aplicam-se separadamente as ações verticais e horizontais. A influência duma camada indeslocável no interior do solo e os efeitos da seqüência construtiva dos edifícios também são analisados.
Soil-structure interaction is the subject of this work. The foremost aim is to verify the real importance of that phenomenon on the structural analysis of usual reinforced concrete buildings on shallow foundations. At first, it is presented a study of soil behaviour. Design procedures of shallow foundations based on NBR 6122 (1996) are described afterwards. Then, the beam and rigid footing elements, used for modelling the superstructure-infrastructure-foundation soil system, are described. It is discussed the modification of the rigid footing element, which represents foundation and soil, to consider a rigid layer within soil. According to the theory above presented, two examples are subjected to two analysis, with or without the consideration of soil-structure interaction, in order to compare the results. Vertical and horizontal loads are separately applied. The influence of a rigid layer within soil and the effects of the sequence of buildings construction are also analysed.

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Farias, Rômulo da Silva. "Análise estrutural de edifícios de paredes de concreto com a incorporação da interação solo-estrutura e das ações evolutivas." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-19022019-104219/.

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As análises estruturais têm como procedimento usual considerar apoios rígidos nas fundações e aplicar as ações de maneira instantânea. Essas duas simplificações podem induzir a uma configuração de esforços não condizentes com a estrutura real. Este trabalho investiga a interação solo-estrutura (ISE) em edifícios de paredes de concreto apoiados em fundação do tipo radier. O presente estudo considera a sequência construtiva da edificação, denominada por ações evolutivas, objetivando obter resultados mais condizentes com a estrutura real. A investigação é realizada mediante simulação numérica utilizando o Método dos Elementos Finitos (MEF) por meio do pacote computacional DIANA®. A tipologia do modelo numérico é baseada em um conjunto de edifícios já construídos. São utilizados dados de monitoramento de recalques geotécnicos ao longo da construção dos edifícios para aferir as propriedades constitutivas do solo no modelo numérico. São analisados os efeitos da deformação da fundação na redistribuição de esforços e tensões das paredes da superestrutura, a contribuição da rigidez da estrutura na uniformização dos recalques e demais parâmetros que envolvem a ISE na estrutura e na fundação. A NBR-16055 (ABNT, 2012) obriga que seja incorporado a interação solo-estrutura nas análises de edifícios de paredes de concreto acima de 5 pavimentos. O presente estudo indica que os efeitos da ISE na estrutura têm uma maior dependência da rigidez relativa estrutura-solo. Deste modo, é proposto um coeficiente específico de rigidez relativa estrutura-solo para edifícios de paredes de concreto. São realizados estudos paramétricos que indicam que o coeficiente proposto pode ser utilizado como um parâmetro para análise da ISE em edifícios de paredes de concreto.
The usual procedure in structural analysis neglects the deformation of the foundations and the load sequence of the building. These simplifications can provide inaccurate results. This work deals with the structural analysis of concrete wall buildings settled on raft foundations taking into account the soil-structure interaction (SSI) and the progressive vertical loading. The numerical simulation was performed using the finite element method (FEM) in the DIANA® software. The numerical model is based on a set of buildings already constructed. During the construction process, the settlement of many points were measured and are used here to evaluate the constitutive soil parameters to feed the numerical models. The obtained results show a redistribution of the walls internal forces and the loss of uniformity of their vertical normal stress. The progressive vertical loading during the construction reduces the influences of the soil-structure interaction. The Brazilian code for concrete wall buildings (NBR-16055, 2012) requires that the soil/structure interaction be incorporated into the structural model in the buildings with more than 5 stories. A specific relative stiffness structural-soil factor is proposed for concrete wall buildings. The present study indicates that the SSI results are not related to the number of floors of the building. The SII have a larger dependence on soil stiffness and relative stiffness structure-soil.

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Jakrapiyanun, Warrasak. "Physical modeling of dynamic soil-foundation-structure-interaction using a laminar container /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3071031.

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文國輝 and Kwok-fai Man. "Elastic solution for rectangular and circular plates on non-homogeneous soil foundation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31208320.

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Man, Kwok-fai. "Elastic solution for rectangular and circular plates on non-homogeneous soil foundation /." [Hong Kong : University of Hong Kong], 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12350679.

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Antoine, Pierre-Cornélius. "Etude des dalles sur sols renforcés au moyen d'inclusions rigides ou non." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209997.

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Soft soil reinforcement by inclusion is a growing technique caracterized by a pile grid and a granular embankment introduced between the reinforced soil and the structure. Unlike traditionnal methods, the load is partially transferred to the pile heads by arching in the embankment. The application area of this research focuses on the shallow foundations case, in which the thickness of the embankment is small. The litterature review shows that only a few studies were dedicated to that case, and that fundamental questions remains concerning the load transfer in the embankment. Chosen method for this research consists in two-dimensionnal physical modelling, analysis of the conducted simulations, and development of an analytical model in order to predict the load transfer to the piles by arching in the embankment. The results of this PhD thesis provide original elements of evidence of the load transfer in the studied system, proposes an analytical model based on block division of the granular embankment by shear bands - which is in good agreement with experimental data - and lead to a better understanding of arching in soils.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

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Moghaddasi, Kuchaksarai Masoud. "Probabilistic Quantification of the Effects of Soil-Shallow Foundation-Structure Interaction on Seismic Structural Response." Thesis, University of Canterbury. Civil and Natural Resources, 2012. http://hdl.handle.net/10092/8446.

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Previous earthquakes demonstrated destructive effects of soil-structure interaction on structural response. For example, in the 1970 Gediz earthquake in Turkey, part of a factory was demolished in a town 135 km from the epicentre, while no other buildings in the town were damaged. Subsequent investigations revealed that the fundamental period of vibration of the factory was approximately equal to that of the underlying soil. This alignment provided a resonance effect and led to collapse of the structure. Another dramatic example took place in Adapazari, during the 1999 Kocaeli earthquake where several foundations failed due to either bearing capacity exceedance or foundation uplifting, consequently, damaging the structure. Finally, the Christchurch 2012 earthquakes have shown that significant nonlinear action in the soil and soil-foundation interface can be expected due to high levels of seismic excitation and spectral acceleration. This nonlinearity, in turn, significantly influenced the response of the structure interacting with the soil-foundation underneath. Extensive research over more than 35 years has focused on the subject of seismic soil-structure interaction. However, since the response of soil-structure systems to seismic forces is extremely complex, burdened by uncertainties in system parameters and variability in ground motions, the role of soil-structure interaction on the structural response is still controversial. Conventional design procedures suggest that soil-structure interaction effects on the structural response can be conservatively ignored. However, more recent studies show that soil-structure interaction can be either beneficial or detrimental, depending on the soil-structure-earthquake scenarios considered. In view of the above mentioned issues, this research aims to utilise a comprehensive and systematic probabilistic methodology, as the most rational way, to quantify the effects of soil-structure interaction on the structural response considering both aleatory and epistemic uncertainties. The goal is achieved by examining the response of established rheological single-degree-of-freedom systems located on shallow-foundation and excited by ground motions with different spectral characteristics. In this regard, four main phases are followed. First, the effects of seismic soil-structure interaction on the response of structures with linear behaviour are investigated using a robust stochastic approach. Herein, the soil-foundation interface is modelled by an equivalent linear cone model. This phase is mainly considered to examine the influence of soil-structure interaction on the approach that has been adopted in the building codes for developing design spectrum and defining the seismic forces acting on the structure. Second, the effects of structural nonlinearity on the role of soil-structure interaction in modifying seismic structural response are studied. The same stochastic approach as phase 1 is followed, while three different types of structural force-deflection behaviour are examined. Third, a systematic fashion is carried out to look for any possible correlation between soil, structural, and system parameters and the degree of soil-structure interaction effects on the structural response. An attempt is made to identify the key parameters whose variation significantly affects the structural response. In addition, it is tried to define the critical range of variation of parameters of consequent. Finally, the impact of soil-foundation interface nonlinearity on the soil-structure interaction analysis is examined. In this regard, a newly developed macro-element covering both material and geometrical soil-foundation interface nonlinearity is implemented in a finite-element program Raumoko 3D. This model is then used in an extensive probabilistic simulation to compare the effects of linear and nonlinear soil-structure interaction on the structural response. This research is concluded by reviewing the current design guidelines incorporating soil-structure interaction effects in their design procedures. A discussion is then followed on the inadequacies of current procedures based on the outcomes of this study.

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Gu, Quan. "Finite element response sensitivity and reliability analysis of Soil-Foundation-Structure-Interaction (SFSI) systems." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3290678.

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Thesis (Ph. D.)--University of California, San Diego, 2008.
Title from first page of PDF file (viewed February 5, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 569-594).

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Balachowski, Lech. "Différents aspects de la modélisation physique du comportement des pieux : chambre d'étalonnage et centrifugeuse." Grenoble INPG, 1995. http://www.theses.fr/1995INPG0067.

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Ce travail de recherche a ete effectue au sein du groupe geomecanique et ouvrages du laboratoire sols, solides, structures. Il concerne l'etude du comportement des pieux de grande dimension utilises comme fondations de structures en mer dans des sables denses. Cette etude a ete menee a l'aide de deux grands outils de modelisation physique: la chambre d'etalonnage du laboratoire 3s et la centrifugeuse du l. C. P. C de nantes. Les pieux installes pour des plates-formes petrolieres sont en general des pieux battus a base ouverte. Les essais de pieux realises en chambre d'etalonnage du laboratoire 3s ont permis d'etudier le comportement du bouchon a l'interieur du tube pendant le battage et le chargement statique. Ils ont montre l'influence de la profondeur simulee, de la densite du massif de sable et de sa surconsolidation sur la mobilisation de la resistance de pointe et du frottement lateral. Une allure plutot parabolique de l'evolution de la resistance de pointe et du frottement lateral avec la surcharge verticale appliquee au massif a ete observee. Les essais penetrometriques realises dans les memes conditions de densite et de confinement ont permis de proposer les regles penetrometriques pour le dimensionnement des pieux en mer. L'extrapolation des resultats de frottement mesure sur le modele au prototype reel peut poser des problemes lies a des effets d'echelle. Les essais d'arrachement de pieux-modeles en centrifugeuse du l. C. P. C de nantes ont permis d'evaluer l'effet d'echelle en frottement lie au rapport taille du modele/ taille des grains. Cet effet d'echelle est exprime en fonction du niveau de contraintes et du rapport taille du modele/ taille des grains. Il est compare a celui qu'on peut determiner a partir d'essais de cisaillement d'interface sol-structure. L'ensemble des experiences menees permet d'une part de deboucher sur des methodes de dimensionnement moins conservatives que celles habituellement utilisees en offshore, d'autre part de confirmer l'importance de la prise en compte du comportement d'interface sol-structure dans la modelisation numerique

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Strand, Tommy, and Johannes Severin. "Soil-Structure Interaction of Pile Groups for High-Speed Railway Bridges." Thesis, KTH, Bro- och stålbyggnad, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231413.

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Soyoz, Serdar. "Effects Of Soil Structure Interaction And Base Isolated Systems On Seismic Performance Of Foundation Soils." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605119/index.pdf.

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In this thesis primarily structural induced liquefaction potential was aimed to be analyzed. Also the effect of base isolation systems both on structural performance and liquefaction potential was studied. FLAC software was chosen for the analyses so that structure and soil could be modeled together. By these means the soil structure interaction effects were also examined. Four different structures and three different sites were analyzed under two different input motions. All the structures were also analyzed as base isolated. It was mainly found that depending on the structural type and for a certain depth the liquefaction potential could be higher under the structure than the one in the free field. Also it was concluded that base isolation systems were very effective for decreasing the story drifts, shear forces in the structure and liquefaction potential in the soil. It was also found that the interaction took place between structure, soil and input motions.

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Yang, Zhaohui. "Development of geotechnical capabilities into OpenSees platform and their applications in soil-foundation-structure interaction analyses /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.

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Pandey, Bishnu Hari. "Investigation of variation of motions between free field and foundation in seismic soil-structure interaction of structures with rigid shallow foundation." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45172.

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Soil-foundation-structure interaction (SFSI) in buildings during earthquakes is characterized by several aspects including the variation between the free-field and foundation motions. Past procedures for analysing the effect of the foundation on the free-field input motions are all based on the assumptions that the foundation slabs always reduce the motion. Recent guidelines, standard and codes including FEMA-440 and ASCE/SEI41-06 also recognize that foundations with interconnected grade beams or concrete slab will always reduce the free-field motions. It implies that SFSI is beneficial and can be conservatively neglected in regular building design practice. A large number of instrumented buildings that have experienced a numbers of earthquakes in the past provide an opportunity to investigate the SFSI effects and evaluate the methods of estimating the foundation motion based on field data. In this research study, investigation is carried out on the records of past earthquakes from sites of instrumented buildings over a wide range foundation configurations and site conditions in California. Analysis of records among 26 buildings that have shallow rigid foundation shows that foundation motions are reduced in two-third cases and amplified in one-third cases. The estimations of variation of motion by the ASCE procedure are not in good agreement, even for the cases of reduction of foundation-base motion. It was obvious that the amplification of the motion cannot be captured by the procedure. Time history simulations of soil-building system have been carried out for varied parameters in 2D continuum finite element models using computer program ABAQUS. The results from simulations confirm that motion may amplify at the foundation depending on period of the building, soil deposit and the predominant period of input motion. This thesis develops a simple mass–spring–dashpot-based system of soil–foundation–structure interaction, called the 3DOF SFS model, for calculating the foundation-base motion that accounts for dynamic interaction between soil, foundation and building. The 3DOF SFS model was verified for a building-structure system with varied parameters and for different input motions using results from ABAQUS. Both amplification and reduction cases of foundation motion compared with free field were predicted by the model.

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Theland, Freddie. "Prediction and experimental validation of dynamic soil-structure interaction of an end-bearing pile foundation in soft clay." Licentiate thesis, KTH, Bro- och stålbyggnad, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-291021.

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In the built environment, human activities such as railway and road traffic, constructionworks or industrial manufacturing can give rise to ground borne vibrations. Such vibrations become a concern in urban areas as they can cause human discomfort or disruption of vibration sensitive equipment in buildings. In Sweden, geological formations of soft clay soils overlying till and a high quality bedrock are encountered in densely populated areas, which are soil conditions that are prone to high levels of ground borne vibrations. Under such soil conditions, end-bearing piles are often used in the design of building foundations. The dynamic response of a building is governed by the interaction between the soil and the foundation. It is therefore essential that models used for vibration predictions are able to capture the dynamic soil-structure interaction of pile foundations. The purpose of this thesis is to experimentally and numerically investigate dynamic soil-structure interaction of an end-bearing pile group in clay by constructing a test foundation of realistic dimensions. The small-strain properties in a shallow clay deposit are estimated using different site investigation and laboratory methods. The results are synthesised into a representative soil model to compute the free-field surface response, which is validated with vibration measurements performed at the site. It is found that detailed information regarding material damping in the clay and the topmost soil layer both have a profound influence on the predicted surface response, especially with an increasing distance from the source. Dynamic impedances of four end-bearing concrete piles driven at the site are measured. Pile-soil-pile interaction is investigated by measuring the response of the neighbour piles when one of the piles in the group is excited. The square pile group is subsequently joined in a concrete cap and measurements of the impedances of the pilegroup and acceleration measurements within the piles at depth are performed. A numerical model based on the identified soil properties is implemented and validated by the measurements. A good agreement between the predicted and measured responses and impedances of the pile group foundation is found, establishing confidence in the ability to predict the dynamic characteristics of end-bearing pile foundations under the studied soil conditions.
Mänsklig verksamhet i urbana miljöer så som väg- och järnvägstrafik, byggnation eller maskindrift inom industri kan ge upphov till vibrationer som sprider sig via marken i närområdet. Dessa vibrationer kan ge upphov till kännbara vibrationer eller påverka vibrationskänslig utrustning i byggnader. I Sverige förekommer ofta mjuka lerjordar ovanpå berg, och inte sällan i tätbebyggda områden. Under sådana jordförhållanden används ofta spetsbärande pålar för grundläggning av byggnader. Det dynamiska verkningssättet för byggnader är beroende av interaktionen mellan jorden och byggnadens grund. Det är därför viktigt att modeller som används för vibrationsanalys i byggnader kan beskriva denna interaktion mellan jord och byggnadsfundament. Syftet med denna avhandling är att experimentellt och via numeriska modeller studera dynamisk jord-struktur-interaktion av ett spetsbärande pålfundament i lera. Jordensmekaniska egenskaper vid små töjningar utvärderas för en lerjord som är avsatt på morän och berg genom både fältförsök och laboratorieanalyser av prover. Informationen kombineras för att konstruera en lagerförd jordmodell av platsen för att beräkna jordens dynamiska respons till följd av en punktlast. Modellen valideras med vibrationsmätningar som utförts på platsen. Studien visar att detaljerad information angående lerans materialdämpning och de mekaniska egenskaperna av jordens översta lager har en stor inverkan på förutsägelser av jordens dynamiska respons vid ytan, speciellt vid stora avstånd från vibrationskällan. Experimentella tester utförs för att mäta dynamiska impedanser av fyra slagna spetsbärande betongpålar. Interaktionen mellan pålarna utvärderas genom att utföra mätningarav de omgivande pålarnas respons till följd av excitering av en påle. Pålgruppen sammanfogas därefter i ett betongfundament och impedanserna samt accelerationer inuti pålarna uppmäts. En numerisk modell baserad på de identifierade mekaniska egenskaperna av jorden upprättas och valideras genom mätningarna. De numeriska resultaten är i god överensstämmelse med de uppmätta vilket styrker användningen av numeriska modeller för att förutsäga interaktionen mellan jord och spetsbärandepålar under de studerade jordförhållandena.

QC 20210302

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Abdelmalak, Remon Melek. "Soil structure interaction for shrink-swell soils a new design procedure for foundation slabs on shrink-swell soils." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2466.

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Yilmazok, Ozgun. "An Investigation Of Accuracy Of Inertial Interaction Analyses With Frequency-independent Impedance Coefficients." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609030/index.pdf.

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AN INVESTIGATION OF ACCURACY OF INERTIAL INTERACTION ANALYSES WITH FREQUENCY-INDEPENDENT IMPEDANCE COEFFICIENTS Yilmazok, Ö
zgü
n M.S., Department of Civil Engineering Supervisor: Assoc. Prof. Dr. B. Sadik Bakir November 2007, 79 pages The inertial interaction between the soil and structure alters dynamic response characteristics of a structure due to foundation deformability, such that the flexibility and energy dissipation capability of surrounding soil may lead to a significant increase in period and damping of structural oscillations. The inertial interaction analyses can be accomplished through utilisation of frequency dependent foundation impedance coefficients that are reported in literature for various soil conditions and foundation types. However, such analyses should be performed in frequency domain, and applicable to only cases that linear structural response is considered. Alternatively, equivalent frequencyindependent foundation impedance coefficients can be employed, such that a constant excitation frequency is assumed in calculation of these coefficients. In this study, it is assumed that the fundamental frequency of a fixed-base structure, which can be obtained through employing available empirical relationships or a modal analysis, can be substituted for excitation terms in impedance expressions. The error induced in calculation of peak structural distortions is investigated through comparisons of structural response due to frequency-dependent and frequency-independent foundation impedance coefficients. For analyses, a linear single-degree of freedom oscillator is considered for modeling the structure. The frequency-dependent impedance of a rigid disk foundation resting on elastic halfspace is simulated by a limited number of discrete elements. The response calculations are performed in frequency domain, through employing 72 acceleration records. It is concluded that, the natural frequency of fixed-base building can be considered as effective excitation frequency for calculation of foundation impedance coefficients, when the effect of inertial interaction on structural response is moderate. Through employing equivalent-linear approximation for the structural response, it is shown that the conclusion is also valid in cases that nonlinear structural response is considered. However, when the inertial interaction has more profound effects on the structural response, the use of natural frequency of flexible-base structure, which is calculated iteratively due to its dependence on foundation-impedance factors is recommended.

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46

Bel, Justin. "Modélisation physique de l’impact du creusement d’un tunnel par tunnelier à front pressurisé sur des fondations profondes." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSET002/document.

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Le travail de thèse présenté dans ce mémoire vise à analyser et à comprendre les mécanismes mis en jeu au niveau de l’impact du creusement d’un tunnel par bouclier à front pressurisé sur des fondations profondes avoisinantes. Cette thèse a été réalisée dans le cadre du projet européen NeTTUN, au sein du Laboratoire de Tribologie et de Dynamique des Systèmes (LTDS) de l’ENTPE. L’approche phénoménologique conduite lors de ces travaux repose sur deux importantes campagnes expérimentales réalisées à l’aide d’un dispositif unique au plan international de modèle réduit 1g de tunnelier à pression de terre (échelle de l’ordre de 1/10eme). La forte originalité de ce dispositif est de pouvoir simuler de façon réaliste les principales étapes du processus tridimensionnel d’excavation mécanisé d’un tunnel. Dans le cadre de cette thèse, le dispositif existant de modèle réduit de tunnelier a dans un premier temps été reconfiguré afin de pouvoir répondre aux besoins du programme expérimental envisagé. Des modèles physiques de fondations profondes (pieux et groupes de pieux) et de barrières de protection ont été conçus dans le cadre des lois de similitude, fabriqués et instrumentés. Deux campagnes expérimentales d’envergure ont été réalisées en massif de sable sec : l’une concerne les effets du passage d’un tunnelier à front pressurisé sur des fondations profondes avoisinantes (pieux, groupe de pieux), l’autre traite de l’efficacité de barrières de protection (parois moulées) utilisées pour limiter ces effets. Différents paramètres qui influencent l’interaction tunnelier - sol - fondations ont été considérés comme la distance relative tunnel / fondation, la pression frontale de soutènement appliquée par le TBM sur le terrain ou encore la hauteur des barrières de protection. L’analyse phénoménologique menée à l’échelle du modèle concerne en particulier l’évolution des champs de contraintes et de déplacements dans le terrain autour du tunnelier, les déplacements relatifs sol - pieu et sol- barrière, la redistribution des efforts au sein des fondations. L’importante base de données et d’analyse ainsi constituée a été mise à profit pour la validation d’outils de modélisation numérique développés par l’Université de Rome au sein du projet NeTTUN
The major goal presented in this thesis was to analyze and investigate the mechanisms, which are involved in the impact of the tunnels excavated thanks to an Earth Pressure Balanced Shield on nearby deep foundations. This thesis was realized in European project NeTTUN and the work had been done in the Laboratory of Tribology and Systems Dynamics (LTDS) of ENTPE. During these works, phenomenological approach was based on two important experimental campaigns carried out using a unique device at the international level of a 1g scale model of earth-pressure tunnel boring machine (scale of the order of 1 / 10). The state of the art of this device was to be able to simulate in possibly realistic way the main stages of the three-dimensional process of mechanized excavation of a tunnel. In the framework of this thesis, the existing model tunneling machine device was initially reconfigured in order to reach the expectations of the experimental program envisaged. Physical models of deep foundations (piles and groups of piles) and protective barriers were designed under the similitude laws, manufactured and instrumented. The two large-scale experimental campaigns have been carried out in a dry sand massif. The first one concerned the effects of the passage of a pressurized tunnel boring machine on nearby deep foundations (piles, group of piles), whereas another one dealed with the effectiveness of mitigation procedure (diaphragm walls) used to limit these effects. Different parameters that influenced on the tunneling: soil - foundation interaction considered as the relative tunnel / foundation distance, the frontal face pressure applied by the TBM in the field or the height of the protective barriers. The phenomenological analysis carried out at the scale of the model concerned in particular the evolution of the fields of stresses and displacements in the ground around the tunnel boring machine, relatives pile / soil and wall / soil displacements and the redistribution of stresses along the pile foundations. The large database and analysis constituted was used for the validation of numerical modeling tools developed by the University of Rome within the NeTTUN project

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47

Cotton, Stephen Andrew. "Two-Dimensional Vibrations of Inflated Geosynthetic Tubes Resting on a Rigid or Deformable Foundation." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9715.

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Geosynthetic tubes have the potential to replace the traditional flood protection device of sandbagging. These tubes are manufactured with many individual designs and configurations. A small number of studies have been conducted on the geosynthetic tubes as water barriers. Within these studies, none have discussed the dynamics of unanchored geosynthetic tubes. A two-dimensional equilibrium and vibration analysis of a freestanding geosynthetic tube is executed. Air and water are the two internal materials investigated. Three foundation variations are considered: rigid, Winkler, and Pasternak. Mathematica 4.2 was employed to solve the nonlinear equilibrium and dynamic equations, incorporating boundary conditions by use of a shooting method. General assumptions are made that involve the geotextile material and supporting surface. The geosynthetic material is assumed to act like an inextensible membrane and bending resistance is neglected. Friction between the tube and rigid supporting surface is neglected. Added features of viscous damping and added mass of the water were applied to the rigid foundation study of the vibrations about the freestanding equilibrium configuration. Results from the equilibrium and dynamic analysis include circumferential tension, contact length, equilibrium and vibration shapes, tube settlement, and natural frequencies. Natural frequencies for the first four mode shapes were computed. Future models may incorporate the frequencies or combinations of the frequencies found here and develop dynamic loading simulations.
Master of Science

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48

Santruckova, Hana. "Inertial loading of soil reinforced by rigid inclusions associated to a flexible upper layer." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00767983.

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Le renforcement des sols en zone sismique par des colonnes ballastées et/ou des inclusions rigides représente une alternative prometteuse et de plus en plus répandue par rapport aux solutions lourdes de fondations sur pieux. On sait que les pieux subissent, du fait de leur rigidité, des moments très importants au niveau de la liaison chevêtre-pieu. Les inclusions rigides surmontées d'un matelas granulaire permettent de mieux dissiper les efforts inertiels transmis par la superstructure, mais peuvent nécessiter des armatures si ce matelas n'est pas suffisamment épais. On peut penser que la colonne à module mixte (CMM) offre une solution combinant l'effet " matelas " à travers sa partie supérieure en colonne ballastée plus flexible et l'effet stabilisateur de la colonne inférieure. Cette thèse présente dans une première partie l'étude expérimentale réalisée au Laboratoire 3S-R (Grenoble) sur des modèles réduits à l'échelle 1/10 afin d'analyser la réponse de ces systèmes sous différentes charges statiques et dynamiques. Le modèle physique se compose d'une semelle carrée reposant directement sur l'argile renforcée. Le chargement vertical et horizontal, statique et dynamique est appliqué par l'intermédiaire de la fondation. Une instrumentation a été placée au niveau de la semelle pour obtenir la réponse globale du système, ainsi que dans la partie rigide inférieure du modèle pour évaluer la répartition des efforts entre inclusion et partie flexible supérieure. Une attention toute particulière a été donnée à la simulation de l'effet inertiel d'un séisme. Les profils de moments, d'efforts tranchants et de déplacements en fonction de la profondeur déterminés à partir de 20 extensomètres répartis régulièrement sur toute la hauteur de la partie rigide ont permis d'étudier l'influence de la hauteur de la colonne ou du matelas. La comparaison entre les déplacements dynamiques de la semelle et les courbes P-y (pression latérale P fonction du déplacement latéral y de la tête de pieu), permet de quantifier la dissipation de l'énergie dans les différentes parties du système. Les résultats expérimentaux montrent que la partie supérieure souple absorbe l'essentiel de l'énergie inertielle sismique. Une modélisation numérique 3D confirme les tendances observées expérimentalement et souligne l'importance du rôle de la zone de transition entre partie souple et partie rigide.

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ARAÚJO, Adrianne Carvalho de. "Análise da interação solo-estrutura em edifícios sobre estacas." Universidade Federal de Goiás, 2009. http://repositorio.bc.ufg.br/tede/handle/tde/1354.

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Made available in DSpace on 2014-07-29T15:18:26Z (GMT). No. of bitstreams: 1 INICIO1.pdf: 76456 bytes, checksum: 67582e2139003c6e0cbd33eceb443ce2 (MD5) Previous issue date: 2009-10-29
The joined structure-foundation analysis of buildings is one of the studied themes of Soil- Structure Interaction (SSI). In this research, a numerical tool was developed using the Matlab program to evaluate the soil-structure interaction in buildings, where the problem has been studied in the last years, but has not became a current practice in civil engineering. The developed program, here named as AIEFE, predict the settlement using the Aoki and Lopes (1975) method, using as input data the reaction loads of building columns, calculated in any subroutine of spatial-portico analysis. The commercial program TQS was chosen as this subroutine in the present research. The found foundation settlements were converted in stiffness values and, then, inputted again in the structural analysis, predicting new settlements, but no more considering the foundations as fixed points . The method is iterative, aiming to reach the settlement (or load) convergence. Two examples of buildings supported by piled foundations were analyzed. The first one presented an almost square plant and the other one was typically rectangular. The SSI effects were analyzed in terms of column loads and also stiffness and foundations settlements during the constructive process of the 15-levels studied cases. During the construction of the first building levels, it was observed a greater load and settlement redistribution, due the lower structural stiffness. Using the foundation stiffness instead of settlement values was considered as an efficient process of convergence. It was also observed that the non-linear foundation behavior had a great influence in the structure load redistribution, even on advanced construction stages when the structure stiffness has a great value.
A análise conjunta da estrutura e da fundação de uma edificação é um dos temas estudados dentro do conceito interação solo-estrutura (ISE). Neste trabalho, desenvolveu-se uma rotina de cálculo no ambiente Matlab para avaliar a interação solo-estrutura em edifícios, onde o tema é estudado há algum tempo, mas que ainda não se tornou prática corrente na engenharia civil. O programa desenvolvido, denominado AIEFE, calcula os recalques das fundações utilizando o método de Aoki e Lopes (1975), utilizando como dados de entrada as reações de apoio dos pilares do edifício vindas de uma sub-rotina de cálculo de pórtico espacial, aqui empregando-se o programa TQS. Os recalques encontrados para as fundações são convertidos em rigidezes e então são inseridos na sub-rotina de cálculo estrutural, onde se processa a estrutura novamente, não mais com apoios indeslocáveis. A metodologia é iterativa de forma a buscar a convergência de recalques ou reações de apoio. Dois exemplos de edifícios apoiados sobre blocos de estacas foram analisados. Um possuía uma geometria em planta aproximadamente quadrangular e o outro retangular. Foram avaliados os efeitos da ISE nas reações de apoio, rigidezes e recalques dos pilares durante o processo construtivo dos 15 pavimentos dos exemplos estudados. Observou-se que nos primeiros pavimentos, devido a menor rigidez da estrutura, tem-se maior redistribuição de carga, recalques e rigidezes nos pilares, e que o processo iterativo em termos de rigidez é bastante eficaz. Verificou-se, também, que o comportamento carga-recalque não-linear das fundações influenciou bastante no comportamento de carga, rigidezes e recalques dos pilares, mesmo em estágios avançados da obra, quando a rigidez da estrutura já era bastante grande.

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Bienen, Britta. "Three-dimensional physical and numerical modelling of jack-up structures on sand." University of Western Australia. School of Civil and Resource Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0208.

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Mobile offshore jack-up drilling rigs are not custom-designed for a particular location but rated for typical operating characteristics, like water depths. They may be deployed at a number of different sites during their design life. Under the current guidelines, the jack-up is required to be assessed for its suitability for each new proposed location, assuming environmental loading conditions due to wind, waves and current corresponding to a 50-year return period storm applicable to the site. Traditionally, these assessments have been performed in two dimensions, simplifying the jack-up to a plane frame and the loading conditions to be in-plane with the rig's 'axis of symmetry'. This thesis introduces a computer program, named SOS_3D, for the fluid-structure-soil interaction analysis of jack-up response in three dimensions. Extensive experimental series have been performed to provide evidence for the generalisation of the foundationsoil interaction model to general six degree-of-freedom loading conditions and its applicability to load paths and stress levels relevant to jack-up spudcans. These experiments included (1) 1g single footing tests, (2) centrifuge single footing tests and (3) centrifuge model jack-up tests. The latter tests highlighted differences in response and mode of failure depending on the loading direction of the jack-up and re-iterated the importance of three-dimensional modelling. The numerical program SOS_3D introduced early in this thesis was shown to represent a useful tool for the prediction of jack-up behaviour under general combined loading in three dimensions. It provided reasonably good, conservative predictions of the experimentally measured jack-up behaviour.

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