Magistrinio darbo tikslas – įvertinti konstrukciją veikiančias apkrovas, apskaičiuoti konstrukcijos pamatų matmenis, apskaičiuoti pastato atskirų pamatų nuosėdžius, palyginti nuosėdžių reikšmes tarpusavyje, rasti santykinių nuosėdžių reikšmes ir įvertinti gretimų pamatų ir geologinių sąlygų nevienodumo įtaką šalia esantiems pamatams; įvertinti skirtingų smėlio frakcijų suspaudžiamumo savybes ir išskirti staigiųjų nuosėdžių dalį, atsirandančių smėliniuose gruntuose apkrovimo metu; pateikti išvadas bei pasiūlymus. Šiame darbe naudojami metodai, sprendiniai ir programos: sumavimo metodas, Businesko sprendinys, programos „STAAD.Pro“; „SCAD“, „MathCad“, „AutoCad“, „Exel“. Magistrinio darbo praktinė reikšmė – praplėsti supratimą apie konstrukcijas veikiančius faktorius, kurie gali labai skirtingai nulemti pagrindo ir pastato tarpusavio sąveiką. Pamatų nuosėdžių skaičiavimai parodė, kad atskirų pamatų nuosėdžiai bei santykiniai nuosėdžiai neviršija leistinų ribų, o gretimų pamatų įtaka gali būti nevertinama, kai atstumas tarp pamatų yra didesnis kaip 7,00 m. Smėlinių gruntų spūdumo savybių, dalelių formos įtakos, smėlinių gruntų elgsenos tyrimai parodė, kad smėliniuose gruntuose staigiosios deformacijos pasireiškia per pirmas 5 s, todėl galima teigti, kad statant statinius ant smėlinio grunto prognozuojami nuosėdžiai įvyksta statybos laikotarpiu. / This masters work purpose is to estimate loadings in construction; calculate foundations dimensions; calculate separate foundations displacements; compare separate foundations displacements between themselves; find relative displacements values and estimate contiguous foundations via geological difference; estimate sand different partical size compression and find primary compression limits when soil is under load; present a report of calculations and laboratory investigations. In this final work was used Businesque problem, summing method and programs: “STAAD.Pro”, “MathCad”, “SCAD”, “AutoCad”, “Exel”. From practical view this work importance is to increase understanding of construction loadings and and factors influence on soil – structure interaction. Calculations of foundations displacements showed that separate foundations and contiguous foundations displacements did not reached their critical magnitudes. Contiguous foundations evaluation to each over could not be accounted then betweeen each over foundation is more than 7,00 m. Sand compression characteristics and sand fraction shape investigation showed that primary compression appears only in first 5 seconds. Because of primary compression all prognosis about total foundation displacement in sand soil estimates when construction is in building period.

In order to meet EU legislation on emissions, significant effort is being invested into the development of cost-effective renewable power generation technologies. The two leading technologies are solar and wind power because of their potential for the lowest levelised cost of energy and for showing a growth in installed capacity and technological development. Various research findings have suggested that significant cost savings in the capital expenditure of renewable energy projects can be made through the optimisation of their support foundations, the understanding of which has formed the main goal of the research.

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.

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.

No description available.

The main objective of this research is to estimate the sizes of riprap (loose rock) on highway or railroad embankments approaching bridges, that would be stable in major floods. Two assumptions about the flow direction were made: one horizontal to the bridge abutment and the other normal to the projection of the bridge abutment. Three dynamic conditions of stability of riprap were observed and classified as shaking, some movement, and large movement (washing out). Shaking is the most conservative criteria for design because it indicates more stability than is necessary, requires larger rock, and is less cost efficient. Some movement suggests a conservative design criteria and is the most desirable because it requires smaller riprap and is therefore less expensive. Large movement or washing out means the least stable condition; it may leave the structure as well as human lives exposed to danger.

This thesis examines possible philosophies to account for the practice of mathematics, exploring the metaphysical, ontological, and epistemological outcomes of each possible theory. Through a study of the two most probable ideas, mathematical platonism and fictionalism, I focus on the compelling argument for platonism given by an appeal to the sciences. The Indispensability Argument establishes the power of explanation seen in the relationship between mathematics and empirical science. Cases of this explanatory power illustrate how we might have reason to believe in the existence of mathematical entities present within our best scientific theories. The second half of this discussion surveys Newtonian Cosmology and other inconsistent theories as they pose issues that have received insignificant attention within the philosophy of mathematics. The application of these inconsistent theories raises questions about the effectiveness of mathematics to model physical systems.

published_or_final_version / Civil Engineering / Master / Master of Philosophy

The de Broglie-Bohm causal interpretation of quantum mechanics is discussed, and applied to the hydrogen atom in several contexts. Prominent critiques of the causal program are noted and responses are given; it is argued that the de Broglie-Bohm theory is of notable interest to physics. Using the causal theory, electron trajectories are found for the conventional Schr??dinger, Pauli and Dirac hydrogen eigenstates. In the Schr??dinger case, an additional term is used to account for the spin; this term was not present in the original formulation of the theory but is necessary for the theory to be embedded in a relativistic formulation. In the Schr??dinger, Pauli and Dirac cases, the eigenstate trajectories are shown to be circular, with electron motion revolving around the <i>z</i>-axis. Electron trajectories are also found for the 1<i>s</i>-2<i>p</i>0 transition problem under the Schr??dinger equation; it is shown that the transition can be characterized by a comparison of the trajectory to the relevant eigenstate trajectories. The structures of the computed trajectories are relevant to the question of the possible evolution of a quantum distribution towards the standard quantum distribution (quantum equilibrium); this process is known as quantum relaxation. The transition problem is generalized to include all possible transitions in hydrogen stimulated by semi-classical radiation, and all of the trajectories found are examined in light of their implications for the evolution of the distribution to the standard distribution. Several promising avenues for future research are discussed.

A suitable subcategory of affine Azumaya algebras is defined and a functor from this category to the category of Zariski structures is constructed. The rudiments of a theory of presheaves of topological structures is developed and applied to construct examples of structures at a generic parameter. The category of equivariant algebras is defined and a first-order theory is associated to each object. For those theories satisfying a certain technical condition, uncountable categoricity and quantifier elimination results are established. Models are shown to be Zariski structures and a functor from the category of equivariant algebras to Zariski structures is constructed. The two functors obtained in the thesis are shown to agree on a nontrivial class of algebras.