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STUDY OF BEARING CAPACITY AND SETTLEMENT OF FOOTINGS IN SILICA SANDS USING DIGITAL IMAGE CORRELATION (DIC)Firas H Janabi (12471888) 28 April 2022 (has links)
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<p>Knowledge of the displacement and deformation fields beneath foundation elements obtained from carefully executed experiments is required to validate state-of-the-art numerical simulations, which in turn enable the development of better foundation design methods. This dissertation presents the results of an experimental program in which load tests were performed on model footings in a half-cylindrical calibration chamber with a transparent viewing window across its diameter. The digital image correlation (DIC) method was used to obtain the strain and displacement fields in the soil from digital images taken during the tests. Tests performed on both smooth and rough footings show a significant dependence of resistance on footing base roughness, with the DIC results providing insight into the reasons for that dependence. The experimental bearing capacity results are used to validate a previously proposed method in which an equivalent friction angle is used for calculation of the bearing capacity of footings in sand.</p>
<p>Schmertmann's method is one of the traditional methods for estimating the settlement of axially loaded footings in sand using cone penetration test (CPT) data. The method was developed for footings placed on the surface of a single, uniform sand layer; it assumes a depth of influence below the footing base within which most of the soil deformations take place and an influence diagram to quantify the influence factor as a function of depth. However, the literature contains limited information on the strain influence diagrams for footings on layered sands, and, as a result, there is no way to accurately account for the effect of sand layering on footing settlement. In this study, Schmertmann's approach for calculating the strain influence factor is modified to account for the effect of two sand layers with varying thickness and relative density. Penetration experiments were performed using a half-square model footing (width <em>B</em> = 90 mm) placed on the surface of both single and two-layered (dense over medium-dense and medium-dense over dense), air-pluviated, silica sand samples prepared inside a half-cylindrical calibration chamber designed for digital image correlation (DIC) analysis. The test results indicate that both the thickness and relative density of the top sand layer (the layer in contact with the footing base) affect the parameters of the strain influence diagram. For dense sand over medium-dense sand, the depth to the peak strain influence factor varies with the thickness of the dense layer; however, when the thickness of the dense layer is 1.5<em>B</em> or greater, the strain influence diagram is similar to that obtained for a single, uniform sand layer. In contrast, for medium-dense sand over dense sand, the peak value of the strain influence factor varies with the thickness of the medium-dense layer up to a value of 1<em>B</em>. Based on the results obtained in this study, new strain influence diagrams are proposed for settlement calculation of square footings on two-layered sand profiles. The proposed method for estimation of footing settlement in layered sand is validated against measured data obtained from a full-scale, instrumented footing load test reported in the literature. </p>
<p>The expressions for the shape and depth factors available in the literature for bearing capacity calculation are mostly empirical and are based on results obtained using limit analysis or the method of characteristics assuming a soil that is perfectly plastic following an associated flow rule. This study presents the results of an experimental program in which load tests were performed on model strip and square footings in silica sand prepared inside a half-cylindrical calibration chamber with a transparent visualization window. The results obtained from the model footing load tests show a significant dependence of footing penetration resistance on embedment depth. The load test results were subsequently used to determine experimentally the shape and depth factors for model strip and square footings in sand. To obtain the displacement and strain fields in the sand domain, the digital image correlation (DIC) technique was used to analyze the digital images collected at different stages during loading of the model footing. The DIC results provide insights into the magnitude and extent of the vertical and horizontal displacement and maximum shear strain contours below and around the footing base during penetration.</p>
<p>The loading of a footing in sand generates substantial shear bands as a mechanism for failure develops with the formation of slip surfaces. The interaction of sand particles in the shear band governs its constitutive response to loading. This study provides the results of loading experiments performed under different conditions on half-square model footings (width <em>B</em> = 90 mm) in dense air-pluviated silica sand samples prepared in a half-cylindrical calibration chamber equipped with an observation window that allows collection of images of the sand domain during testing. Two sands (Ottawa sand and Ohio Gold Frac sand) with different roundness (angularity) were used to perform these experiments. The digital image correlation (DIC) technique was used to obtain the incremental strain fields in the sand domain. The zero-extension line (ZEL) concept was then used to study the shear strain localization process and to obtain the orientation of the shear bands from analysis of the incremental strain fields. The results show that sand particle morphology, footing surface roughness, load eccentricity, and depth of embedment of the model footing have an impact on the dominant shear band patterns that develop below the model footings, and, as a result, all of these factors affect the unit bearing capacity of footings. The estimated thickness <em>t</em>s of the shear band from the experiments is approximately 6<em>D</em>50 for Ottawa sand and approximately 8<em>D</em>50 for Ohio Gold Frac sand. </p>
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Zázemí sportovního areálu / Facilities of sports complexMach, Daniel January 2018 (has links)
The diploma thesis deals with a new construction of a sports complex facility in Žďár nad Sázavou, Vysočina region. It aims to develop project documentation for construction work. The building is located near the town’s centre, on the unconstructed land under the town’s ownership. The object is supposed to serve as a facility for athletes. The building’s plan is regularly-shaped, formed to the letter “L”. It has two above-ground and one underground floors. In the object, there are a wellness area, gym, dressing room, restaurant, administrative part, and an apartment for the manager of the building. This is a classic brick building, which is based on both strip foundations and square footings. Bearing perimeter walls in the underground floor are formed from lost formwork. Bearing perimeter walls in the above-ground floors are formed from Porotherm cut ceramic blocks. The ceilings are made of Spiroll panels. Partition walls consist of Porotherm non-bearing cut ceramic blocks. The object is roofed by a flat single-skin roof and a vegetation roof. All external walls are insulated with a contact thermal insulation system.
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Sportovní hala / Sports HallZogata, Pavel January 2015 (has links)
In my diploma thesis the proposal is developed as supporting steel structure sports hall with dimensions 45 x 54 m, a maximum height of 15.5 meters,for the area of Znojmo. In a static calculation are designed and assessed the main bearing structural components such as solid panel purlins, spatial lattice truss, bracing and solid panel columns, which together with the truss form create a crosslinks, column bases and anchoring, plus Tribune.The work includes the design documentation consisting of a layout drawing, drawing anchoring and drawing selected details.
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Společenský dům / The Social HouseBíza, Petr January 2015 (has links)
The diploma thesis focuses on project of new building of social house in Mutěnice in Hodonín district in South Moravian region. The project is in accordance with official assignment and with contemporary Czech standards and legislation. The building is placed in inner part of the town close to the town centre. It’s designed on an empty plot owned by town. Object should serve to the town citizens as cultural and social meeting point. The building plan is irregullarly-shaped with maximum dimensions 29,5 X 52,0 m and has two floors. Inside the social house there is a dance hall, restastaurant with kitchen and rooms for cultural and social activities of citizens of Mutěnice. Structural system can be divided into two parts. The part of the building with dance hall consists of feinforced concrete frames combined with infill masonry walls. The other part with restaurant and other rooms is made of masonry walls. The foundations of the building are made of concrete strip foundations and reinforced concrete square footings with grade beams. Bearing walls are made of sand-lime blocks KM Beta. Ceilings are made of prestressed concrete floor slabs Spiroll. Partition walls consist of plasterboard panels. The building is roofed by flat extensive green roof. All external walls are insulated with mineral wool. Doors and windows have wooden frames and triple glazing. As result there’s structurally, operationally and aesthetically functional complex, that will be benefit for the town and its citizens, especially for their cultural and social life.
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