Mobile jack-up rigs are widely used in offshore oil and gas exploration and increasingly in temporary production and maintenance work. There is a steadily increasing demand for their use in deeper water and harsher environments. A typical modem jack-up has three independent legs, each equipped with a footing known as ‘spudcan’. This thesis is concerned with the performance of spudcan foundation subjected to vertical loading correspondent to preloading during its installation into uniform clay. The chief aim of this study is to investigate the bearing behaviour with the corresponding soil failure mechanisms during spudcan penetration. Centrifuge model test and Finite Element (FE) analysis are carried out extensively. In centrifuge modelling, a half-spudcan model and a full spudcan model are used. In the half- spudcan model test, a novel system for revealing soil failure mechanisms and measuring soil deformation has been adopted, in which the half-spudcan model is placed against a transparent window and a subsequent Particle Image Velocimetry (PIV) analysis is performed. The full-spudcan model test is conducted to measure the load-penetration response. In numerical simulation, both small strain and large deformation analyses are carried out with smooth and rough soil-spudcan interfaces considered. At the initial stage of penetration, it is observed that a cavity is formed above the spudcan as it is penetrating into a uniform clay. Meanwhile, soil flows towards the surface and thus soil heave forms close to the spudcan shoulders. With further penetration, the soil underneath the spudcan starts to flow back into the cavity on the exposed top of the spudcan. This backflow causes the spudcan to be embedded while the initially formed cavity remains open. / Eventually, the spudcan becomes fully embedded and the soil flow mechanism reaches a fully localised failure mechanism with deep embedment. The lateral extent of visible distortion due to soil flow is confined well within 1.5-1.6 D (D: spudcan diameter). From both centrifuge and numerical investigations, it is found that in uniform clay, it is inevitable to form a cavity above the spudcan foundation. Thus, the stable cavity depth and soil back flow mechanisms are studied. It is clear that the back flow is caused by a Flow Failure, where it is due to the downward penetration of the spudcan. This is contrary to the Wall Failure that is the mechanism recommended by the current offshore design guidelines to estimate the stable cavity depth. In wall failure, the soil back flow is due to the cavity wall too high to stand. The stable cavity depth is estimated up to 4 times higher by the wall failure mechanism than the one by the flow failure. This explains that the wall failure is never observed in model test. Therefore, a new design chart with design formula is developed for design engineers in the stable cavity depth calculation. The spudcan bearing response is strongly correspondent with the variation of soil failure mechanisms during penetration. At the initial stage of the penetration, the spudcan bearing capacity increases with penetration, which is due to the increase of overburden pressure from cavity formation. At the second stage of the penetration, soil back flow embeds the spudcan, and the spudcan bearing capacity is increasing as the soil flow mechanism transits from its shallow failure mechanism to its deep failure mechanism. / At the final stage of the penetration, the spudcan bearing capacity reaches its ultimate value, where the deep/localised failure mechanism remains. A rough spudcan shows 14 % higher bearing capacity than a smooth spudcan. And a flat-plate shows 8 % higher capacity than a spudcan with a same surface roughness. The ultimate bearing capacity factor N, = 10.5 in uniform soil is recommended as a conservative value when the deep failure mechanism is reached. A correspondent N, = 10.1 in NC clay is suggested for a deeply embedded spudcan.

This report deals with the fire resistance of cross-laminated timber (CLT). Themain purpose is to verify a new model on CLT and its ability to sustain itsbearing capacity when exposed to fire. To establish this, a series of bendingtestshas been conducted in combination with fire exposure of the CLT. Twodifferent series, with different dimensions, of beams were tested (series 1 andseries 2). Four basic set-ups: CLT in tension or compression, either equippedwith fire protective covering or not. Results from the tests has been gatheredand evaluated to verify the theoretical model of the fire resistance. Evaluationwas made through analysis of the residual cross-sections of the beamsregarding charring depth and rate and moment of inertia (I).Results of the tests verify to a large extent the Design model. Externalproblems and variations in the beams themselves caused some deviations.Analysis confirmed the CLT as being more similar to other laminated productssuch as Laminated Veneer Lumber (LVL) then homogenous solid beams. BothCLT and LVL experience delamination when exposed to fire resulting in anincreased charring rate. The difference in rate when using Gypsum plaster as aprotective barrier against the fire exposure is also equal to LVL.The results of the report will be used in the new version of the EuropeanStandard, Euro Code 5 and in the third edition of Fire Safe Timber Buildings.Charring rates proved to be less than expected but the CLTs ability to withstandfire while keeping its bearing capacity

This work deals with the bearing capacity of wood based I-joists Finite element models were analyzed to determine the bearing capacity of I-joists, using the finite element software Abaqus CAE. The purpose of this study is to compare the results from the developed FE-models with experimental results, and with a previously proposed design formula. To perform the analyses finite element models were created. The model consists of three parts:, the web (made of shell element), the flanges and steel plates used at the supports and loading points (made of solid elements) To determine the bearing capacity of the I-joist two types of analyses were performed, a linear buckling analysis to check the risk of web buckling and a static (stress) analysis to check the risk of splitting of the flanges. This study shows that the steel plate length, in some cases, has little or no impact on primarily the splitting load. Furthermore, the buckling load decreases as the depth of the beam increases, the influence of the depth being proportional to 1/h2. The depth of the beam has no impact on the risk of splitting of the flange.

The different material layers as part of a road construction fill all a function so theroad becomes durable, safe, comfortable and aesthetically pleasing. Recently, anew group of construction materials started to play an important role in roadconstruction – geosynthetics. This thesis addresses the two most common types ofgeosynthetics used in modern road construction, namely geogrids and geotextiles.The most common use of geogrids is reinforcement of poor subgrade by usinggeogrid soil reinforcement, which occurs when road material particles wedge inthe geogrid’s mesh. Geotextiles act partly as a barrier that prevents the finermaterial in the below ground from being mixed with coarser upper material andalso act as a load spreader.Road contractors often face a choice of whether geogrids and/or geotextiles areappropriate in a particular road project and also how much profit the choice mightbring. This phase in the tender calculation process is the intended scope of thisthesis. The thesis deals with both the "hard" cost-function aspects and the "softer" values e.g. ecology and social aspects. To facilitate the comparison, a comparative modelwas developed. The comparison is done for two different cases: Case A – roadconstruction on the bank and Case B – road construction in hill cutting. In Case A “with geogrid”, the amount of trenching becomes smaller due to saving ofreinforcement layer thickness.The completed cost comparison indicates an opportunity for significant savings forroad contractors that choose to strengthen the road’s superstructure with geogrid. In Case A “with geotextile”, no trenching saving is likely, but instead, bearingcapacity improvement is a long term financial gain. An estimated cost for Case B “hill cutting road”, is approximately SEK 600 000 which is less than the cheapestcase i.e. Case A “with geogrid”. After the use of geogrids, the function changes are as following: Traffic load distribution on the terrace has increased and lateral landmovements have reduced Filling material density has increased due to geogrid wedging mechanism Frictional resistance has increased due to the fact that pavement materialparticles have been extended due to geogrid’s wedging mechanism Superstructure’s total thickness has been reduced due reinforcement layerthickness’s reduction After the use of geogrids, the function changes are as following: The composition and function of the road pavement and terrace materialremains intact. (The words "remains intact" run true to the concept of"functional change" but in this case, it is meant that the materialcomposition and function could have been worse if not properly chosengeotextile was added to the design). The scenario "gritty mud" is avoided if the geotextile has been enteredcorrectly with the right overlap. Results concerning the ecological aspects show that the trenching reduction due touse of geogrids leads to fewer ground motion, lesser soil degradation and fewerenvironmental harmful emissions because the use of road construction equipmentdeclines. Reduced distribution excavation thanks to geotextiles leads to both thesame advantages as in the sentence above and partly to the fact that the amount ofmaterials that need become deposited decreases. In addition, the risk ofgroundwater lowering due to artificial drainage ditch is minimized. The road'stotal life cycle is extended, which contributes to reducing the environmentalimpacts arising from road repair and construction of a new road if the old onestops fulfilling its function. Degradation of geogrids and geotextiles is notenvironmentally harmful, but takes a long time in natural conditions, which meansthat in practice, the use must be documented and taken care of (regarding finalcombustion in a prudent manner).Regarding social sustainability, the following conclusion could be drawn: a roadthat has a higher carrying capacity leads to higher traffic safety due to minimalsubsidence, track formation and cracking. Road safety is seen by citizens not onlyas something that the private motorists are responsible for but also something thatroad authorities should consider when planning for a socially sustainable society.Another conclusion is road maintenance frequency and hereby the taxpayers' longtermeconomic gain. The road extended total life cycle contributes to the reductionof road repairs and new construction of roads. In other words, it is not just “oneroad construction company” that wins economically by minimizing their warrantywork. The discussion concerns the cases where geosynthetics are not economicallyoptimal bearing capacity choice, such as solid rock cutting or a stretch of roadwhich has weaker parties but for which, a filling material yet compensates for theexcavated. The report concludes with a special discussion of the Swedishgeosynthetics research. The geosynthetics industry is controlled by private actors(developers, manufacturers and others) and contractors who do not like releasinginformation that might reduce their competitiveness. Therefore, the independentresearcher’s role has been quite weak and mostly reduced to “play ‘catch-up’insofar as investigating the nuances of how geosynthetics work "(Koerner, 2005). Another reason for the lack of reports on geosynthetics benefit is the long term asa sharp research project takes to plan, implement, control and evaluate. WhilstTrafikverket’s and local municipalities’ play the leading role in the Swedish roadconstruction industries, it should be in their interest to start taking geosyntheticsmore seriously by implementing credible tests and full scale trials and publishpractically applicable documents based on objective tests of structures containing geosynthetics.

<p>This report deals with the fire resistance of cross-laminated timber (CLT). Themain purpose is to verify a new model on CLT and its ability to sustain itsbearing capacity when exposed to fire. To establish this, a series of bendingtestshas been conducted in combination with fire exposure of the CLT. Twodifferent series, with different dimensions, of beams were tested (series 1 andseries 2). Four basic set-ups: CLT in tension or compression, either equippedwith fire protective covering or not. Results from the tests has been gatheredand evaluated to verify the theoretical model of the fire resistance. Evaluationwas made through analysis of the residual cross-sections of the beamsregarding charring depth and rate and moment of inertia (I).Results of the tests verify to a large extent the Design model. Externalproblems and variations in the beams themselves caused some deviations.Analysis confirmed the CLT as being more similar to other laminated productssuch as Laminated Veneer Lumber (LVL) then homogenous solid beams. BothCLT and LVL experience delamination when exposed to fire resulting in anincreased charring rate. The difference in rate when using Gypsum plaster as aprotective barrier against the fire exposure is also equal to LVL.The results of the report will be used in the new version of the EuropeanStandard, Euro Code 5 and in the third edition of Fire Safe Timber Buildings.Charring rates proved to be less than expected but the CLTs ability to withstandfire while keeping its bearing capacity</p>

Baigiamajame magistro darbe apžvelgti metodai spraustinių polių laikomajai galiai nustatyti. Nagrinėtos dvi metodų grupės – analitiniai ir empiriniai, pagrįsti statinio zondavimo duomenimis. Pagrindinis darbo tikslas yra išanalizuoti ir palyginti nagrinėjamus metodus. Taip pat jie gretinami su eksperimento rezultatais, kas leidžia įvertinti ne tik skirtumus tarp jų, tačiau ir tinkamumą Lietuvos geologinėmis sąlygoms. Eksperimentinę – tiriamąją dalį sudaro geologinio kūno, kuriame įrengti bandomieji poliai, fizikinių – mechaninių savybių apibūdinimas ir polių bandymų įrangos, eigos ir rezultatų aprašymas. Nustatyti pagrindiniai metodų skirtumai, palygintos apskaičiuotos vertės su eksperimento duomenimis. Pateikiamos išvados ir siūlymai tolesniems tyrimams. Darbą sudaro tokios dalys: įvadas, polio apkrovos perdavimas pagrindui, analitinių polio laikomosios galios skaičiavimo metodų apžvalga, empirinių polio laikomosios galios skaičiavimo metodų apžvalga, metodų apibendrinimas, polių bandymas gniuždančia statine apkrova, apskaičiuotų ir eksperimentinių laikomųjų galių gretinimas, išvados ir pasiūlymai, literatūros sąrašas. Darbo apimtis – 64 p. teksto be priedų, 28 iliustr., 10 lent., 39 bibliografiniai šaltiniai. Pridedami darbo priedai. / In master thesis reviewed methods to determine bearing capacity of displacement piles. Two groups of methods analysed – analytical and empirical (based on cone penetration test data). The main aim of the thesis is to overlook and compare with highliting differences of the methods. Also the calculated data is compared with test results. This allows to evaluate the suitability of the methods for Lithuanian geological conditions. Experimental part consists of characteristation of physical – mechanical properties of the geological body where test piles was installed. Also description of test equipment, procedure and results made. Main differences of the methods obtained and test data with calculated values compared. Conclusions and proposals for further investigation represented. Structure: introduction, transmission of pile load to soil, review of analytical methods for determination of pile bearing capacity, review of empirical methods for determination of pile bearing capacity, pile tests on static axial load, comparison of calculated and measured from pile tests results values, conclusions and suggestions, references. Thesis consist of: 64 p. text without appendixes, 28 pictures, 10 tables, 39 bibliographical entries. Appendixes included.

The methods of analysis used to determine ultimate bearing capacity of piles are applied to a field case in Turkey. During the pile driving works of the Atat&uuml / rk Culture Center in Samsun, Delmag D22-13 and Delmag D-15 diesel pile driving hammers have been used. The ultimate bearing capacity and skin friction values calculated using static formulas have been given as input to the wave equation pile analysis program FADWAVE written by J.E.Bowles. The analytical method used in this program was based on the wave propagation in solids originated in 1962 by E.A.L.Smith. The results obtained from the program are compared with each other.

O presente trabalho tem como objetivo avaliar a utilização de um penetrômetro manual para quantificar a resistência à penetração em um solo poroso e não-saturado. Os ensaios foram efetuados com monitoração de sucção, obtendo-se assim correlações entre resistência à penetração do penetrômetro e a sucção do solo. Os valores de tensão de ruptura obtidos nos ensaios penetrométricos foram comparados com valores de capacidade de carga de ensaios de placa e de provas de carga em sapatas realizados à mesma profundidade, no mesmo local, com medidas simultâneas de sucção. Finalmente, o trabalho comprova a influência da sucção nos resultados dos ensaios realizados / The objective of this work is to evaluate the use of a hand penetrometer to quantify the penetration resistance of a porous and unsaturated soil. The tests were done with suction monitoring, thus, it was obtained correlation between resistance of the penetrometer penetration and the soil suction. The values of rupture pressure obtained by the penetrometer tests were compared with values of bearing capacity of plate load tests and footing load tests, that were done at the same deep and at the same location, with suction measurement. Finally, this work proves the influence of the suction on the tests results

La evaluación de la capacidad de carga de pilotes juega un rol esencial en su diseño. Esta capacidad puede ser estimada por metodologías teóricas, soluciones analíticas o numéricas, o por métodos semi-empíricos, cuyas aplicaciones están generalmente basadas en resultados de ensayos en campo. Las formulaciones semi-empíricas son comúnmente las más usadas por ingenieros geotécnicos debido a que los métodos teóricos generalmente están limitadas a aplicaciones particulares. Esta investigación compara la capacidad de carga de pilotes excavados por medio de diferentes metodologías, basándose en pruebas de carga experimentales llevadas a cabo en los campos experimentales de la universidad de Brasilia y Campinas, en Brasil. Los métodos semi-empíricos determinan la capacidad de carga ya sea a través del control del asentamiento o extrapolación de la curva carga x asentamiento mientras que los métodos teóricos están basados tanto en soluciones analíticas como numéricas, siendo la última mencionada calculada a través del análisis de los elementos finitos. Las comparaciones que se dieron de las capacidades de carga medidas en pruebas de carga con las obtenidas en resultados numéricos y del control de asentamiento mostraron buenos resultados, mientras que se encontraron valores con mayores errores relativos de los esperados al compararse con las metodologías semi-empíricas. El caso del método teórico presentó conservativos resultados siempre y cuando se considerase el efecto de la fricción negativa. The evaluation of axial bearing capacity of piles plays an essential role in their design. It can be estimated by theoretical methods, through an analytical or numerical solution, or by semi-empirical methods, whose application is generally based on field test results. Semi-empirical formulations are often preferred by geotechnical engineers since theoretical approaches are generally limited to particular applications. This paper compares the axial bearing capacity of bored piles estimated by different methodologies, based on instrumented load tests carried out in both the Campinas and Brasilia university campus, in Brazil. The semi-empirical approach involved settlement control and extrapolation of load-settlement curve while the theoretical approach was based on both analytical and numerical solutions, the latter computed through finite element analyses. When compared to the ultimate load bearing capacity measured in the instrumented load tests, both numerical and the settlement control results showed close agreement, while the semi-empirical methods estimated major expected relative errors and the theoretical method presented conservative values when considering the negative skin friction effects.

O presente trabalho tem como objetivo avaliar a influência do efeito da corrosão no comportamento geotécnico de condutos enterrados através da utilização de ensaios em modelos reduzidos. Foram empregados diferentes padrões de corrosão, em que se variou o grau e a localização da corrosão. Os resultados do trabalho mostram as localizações mais danosas à estrutura, correlacionando resultados dos tubos corroídos com os de tubos intactos. O duto danificado desencadeou um carregamento assimétrico que deve ser considerado para a prevenção de possíveis deslocamentos. Finalmente, o trabalho avalia a influência conjunta da corrosão e da flexibilidade do conduto no comportamento mecânico das tubulações enterradas. De modo a permitir comparações para averiguar a validade do modelo laboratorial adotado, utilizaram-se simulações numéricas, que possibilitam o estudo do problema de forma mais abrangente. / This work evaluates the influence of corrosion effect on the geotechnical behavior of underground conduits. Small-scale tests were carried out on two different types of pipes, in which the degree and location of the corrosion were changed. The results show the most harmful corrosion locations relative to the intact conduits. The damaged conduits built in and located under asymmetric condition behave as if they were subjected to an asymmetric loading condition and this must be considered to the prevention of possible displacements. Finally, the work evaluates the joined influence of the corrosion and conduit\'s flexibility on the mechanical behavior of underground pipelines. To allow comparisons to inquire the validation of the adopted laboratorial model, numeric simulations were used, which enable the study of the problem considering other corrosion layouts.