Heavy forestry machines have great immediate effect on soil properties. This increases the interest to develop approaches that help understanding better the interaction between the forest machines and the terrain and consequently develop the forwarders to be gentle to the environment. The most predominant indications of soil disturbances caused by harvesting are mainly rutting and soil compaction. It is critical to understand and evaluate these damages to be able to protect the remaining trees and improve their tree growth rate. Comprehending the bearing capacity of the soil and the interaction between tire and soil are the key issues to develop forest machines that preserve the terrain. The first step to accomplish this goal is to compare the rut depth theoretical data from empirical models with the rut depth data from a full scale field test, the models suitable to predict rut depth is descripted. Tree roots reinforce the forest floor and significantly increase the bearing capacity of the soil. The contribution from root layer to the soil bearing capacity depends on the number, diameter, orientation of the roots and their mechanical properties. To improve the root tensile strength model, a root bending and stretching laboratory test has been carry out and compared with FEM-based results. The existing Valmet 860. 3 Adams MBS model is finally used to study the suitability of the model to predict rut depth. A comparison between several existing methods to predict rut depth is also shown. / Tunga skogsmaskiner har stor omedelbar effekt på markens egenskaper. Detta ökar intresset för att utveckla strategier som underlättar förståelsen av samverkan mellan skogsmaskiner och terrängen och därmed utveckla framdrivning av dessa maskiner som är skonsam mot miljön. De dominerande indikationerna på markstörningar orsakade av hjulbaserade skogsmaskiner är främst spårbildning och jordkompaktering. Det är viktigt att förstå och utvärdera dessa skador för att kunna skydda de kvarvarande träden och förbättra deras tillväxt. Att förstå markens bärighet och samspelet mellan däck och mark är de viktigaste frågorna för att utveckla skogsmaskiner som skonar terrängen. Det första steget för att uppnå detta mål är att jämföra spårdjup vilka är framtagna med empiriska modeller med data för spårdjup från ett fullskaligt fälttest, där de modeller som lämpar sig för att förutsäga spårdjup är beskrivna. Trädrötter förstärker skogsmarken och ökar avsevärt jordens bärighet. Bidraget från rotlagret till jordens bärförmåga beror på antalet rötter, deras diameter samt rötternas orientering och deras mekaniska egenskaper. För att förbättra modellen för rötternas mekaniska egenskaper har rotböjning och rottöjning studerats i ett laboratorietest och vidare jämförts med FEM-baserade resultat. Den befintliga MBS modellen av skotaren Valmet 860.3 har slutligen används för att studera lämpligheten av modellen för att förutsäga spårdjup. En jämförelse mellan flera olika metoder för att förutsäga spårdjup visas också.

A nonlinear finite element analysis was performed for an existing road bridge in order to see if that could show a higher load bearing capacity, as an alternative to repairing or replacing. The regular linear analysis had shown that the bridge could not take any traffic load due to the effects from large and uneven support settlements. It is a five-span reinforced concrete bridge with a continuous slab on supports made out of rows of columns. The width-to-span ratio was around 1 and the supports were angled up to about 30°, giving rise to a complex three-dimensional behaviour, which was seen and studied in the nonlinear results. Since the bending moment was the limiting factor, the nonlinear analysis focused on that. The direct result was that the load bearing capacity was 730 kN for the traffic vehicle boogie load, B, in the ultimate limit state. This was however only for the load case tested, and several more disadvantageous vehicle positions may exist. Other aspects also became limiting, as the maximum allowed vertical deflection in the serviceability limit state was reached at 457 kN. The most restraining though, was the shear capacity from the linear analysis; 78 kN, since it was not possible to simulate that type of failure with the shell elements used in the nonlinear finite element analysis. The main aim of the thesis was nonetheless reached, since the nonlinear analysis was able to show a significant increase in load bearing capacity.  A comparison was made with the settlements for the nonlinear case, to see how much influence they had on the load bearing capacity for traffic load. This was performed for both the bridge and a simple two-span beam. Both showed that there was no effect on the load bearing capacity in the ultimate limit. One thing to note was that the full settlements were applied, and with no relaxation due to creep.  Another aim of the thesis was to make comments on the practical usability of the nonlinear finite element method in load bearing capacity assessments. A linear analysis was performed before the nonlinear in order to be able to determine the load case to be used in the latter. This worked well, as the strengths of the two methods could then be utilized. Convergence problems were however encountered for the nonlinear when using the regular static solver. Due to this, the dynamic explicit calculation scheme was used instead, treating the case as quasi-static. This managed to produce enough usable results. It was concluded that the nonlinear finite element method is useable for assessment calculations, but that its strengths and weaknesses must be known in order to make it an efficient method.

Over the past 50 years, several advancements have been made in the research area of the mechanics of unsaturated soils. These advancements can be categorized into two groups; (i) development (or improvement) of testing techniques (or apparatus) to determine the mechanical properties of unsaturated soils and (ii) development of (numerical, empirical or semi-empirical) models to estimate the variation of mechanical properties of unsaturated soils with respect to suction based on the experimental results. Implementation of the mechanics of unsaturated soils in conventional geotechnical engineering practice, however, has been rather limited. The key reasons for the limited practical applications may be attributed to the lack of simple and reliable methods for (i) measuring soil suction in the field quickly and reliably and (ii) estimating the variation of mechanical properties of unsaturated soils with respect to suction. The main objective of this thesis research is to develop simple and reliable techniques, models or approaches that can be used in geotechnical engineering practice to estimate sol suction and the mechanical properties of unsaturated soils. This research can be categorized into three parts. In the First Part, simple techniques are proposed to estimate the suction values of as-compacted unsaturated fine-grained soils using a pocket penetrometer and a conventional tensiometer. The suction values less than 300 kPa can be estimated using a strong relationship between the compressive strength measured using a pocket penetrometer and matric suction value. The high suction values in the range of 1,200 kPa to 60,000 kPa can be estimated using the unique relationship between the initial tangent of conventional tensiometer response versus time behavior and suction value. In the Second Part, approaches or semi-empirical models are proposed to estimate the variation of mechanical properties of unsaturated soils with respect to suction, which include: - Bearing capacity of unsaturated fine-grained soils - Variation of bearing capacity of unsaturated fine-grained soils with respect to matric suction - Variation of initial tangent elastic modulus of unsaturated soils below shallow foundations with respect to matric suction - Variation of maximum shear modulus with respect to matric suction for unsaturated non-plastic sandy soils (i.e. plasticity index, Ip = 0 %) In the Third Part, approaches (or methodologies) are suggested to simulate the vertically applied stress versus surface settlement behavior of shallow foundations in unsaturated coarse-grained soils assuming elastic-perfectly plastic behavior. These methodologies are extended to simulate the stress versus settlement behavior of both model footings and in-situ plates in unsaturated coarse-grained soils. The results show that there is a reasonably good comparison between the measured values (i.e. soil suction, bearing capacity, elastic and shear modulus) and those estimated using the techniques or models proposed in this thesis research. The models (or methodologies) proposed in this thesis research are promising and encouraging for modeling studies and practicing engineers to estimate the variation of mechanical behavior of unsaturated soils with respect to matric suction.

[pt] O interesse por análises de confiabilidade em geotecnia tem aumentado muito nos últimos anos. Métodos probabilísticos tem sido utilizados com o objetivo de racionalizar a quantificação das incertezas existentes na geotecnia. Neste âmbito, o presente trabalho apresenta um resumo com os conceitos básicos de probabilidade necessários para a compreensão do assunto. Desenvolve-se o Método do Segundo Momento de Primeira Ordem para quantificação da confiabilidade inerente ao desempenho de fundações. Metodologias são propostas para racionalizar a adoção de fatores de segurança quanto à ruptura de fundações superficiais e quantificar o risco associado à probabilidade do recalque estimado ser superior ao recalque admissível. Os exemplos de cálculo são apresentados com base no desempenho de fundações protótipo submetidas a provas de carga superficiais executadas no campo experimental 1 da PUC-Rio. / [en] The interest for reliability analysis in geotechnical engineering has been growing up in the last two decades. Probabilistic methods are generally used as a way of rationalizing the analysis of the uncertainties presents in the geotechnical properties. The First Order Second Moment method (FOSM) was applied in order to quantify the reliability of foundations. A methodology is proposed for quantifying the probability of faylure of shallow foundations and also the probability of settlements larger than the allowable design value. Example calculations are presented with basis on the results of prototype footings tested in the experimental research site at PUC-Rio. / [es] EL interés por análisis de confiabilidad en geotecnia ha aumentado mucho en los últimos años. Métodos probabilísticos han sido utilizados con el objetivo de racionalizar la cuantificación de las incertezas que existen en la geotecnia. En este ámbito, el presente trabajo presenta un resumen de los conceptos básicos de las probabilidades, necesarios para la comprensión del asunto. Se desarrolla el Método del Segundo Momento de Primer Orden para cuantificar la confiabilidad inherente al desempeño de fundaciones. Se proponen metodologías para racionalizar la adopción de factores de seguridad y cuantificar el riesgo asociado a la probabilidad de que el recalco estimado sea superior al recalco admisible. Los ejemplos de cálculo presentados tienen como base el desempeño de fundaciones prototipos, sometidas a pruebas de carga superficiales, ejecutadas en el campo experimental 1 de la PUC-Rio.

A nonlinear finite element analysis was performed for an existing road bridge in order to see if that could show a higher load bearing capacity, as an alternative to repairing or replacing. The regular linear analysis had shown that the bridge could not take any traffic load due to the effects from large and uneven support settlements. It is a five-span reinforced concrete bridge with a continuous slab on supports made out of rows of columns. The width-to-span ratio was around 1 and the supports were angled up to about 30°, giving rise to a complex three-dimensional behaviour, which was seen and studied in the nonlinear results. Since the bending moment was the limiting factor, the nonlinear analysis focused on that. The direct result was that the load bearing capacity was 730 kN for the traffic vehicle boogie load, B, in the ultimate limit state. This was however only for the load case tested, and several more disadvantageous vehicle positions may exist. Other aspects also became limiting, as the maximum allowed vertical deflection in the serviceability limit state was reached at 457 kN. The most restraining though, was the shear capacity from the linear analysis; 78 kN, since it was not possible to simulate that type of failure with the shell elements used in the nonlinear finite element analysis. The main aim of the thesis was nonetheless reached, since the nonlinear analysis was able to show a significant increase in load bearing capacity. A comparison was made with the settlements for the nonlinear case, to see how much influence they had on the load bearing capacity for traffic load. This was performed for both the bridge and a simple two-span beam. Both showed that there was no effect on the load bearing capacity in the ultimate limit. One thing to note was that the full settlements were applied, and with no relaxation due to creep. Another aim of the thesis was to make comments on the practical usability of the nonlinear finite element method in load bearing capacity assessments. A linear analysis was performed before the nonlinear in order to be able to determine the load case to be used in the latter. This worked well, as the strengths of the two methods could then be utilized. Convergence problems were however encountered for the nonlinear when using the regular static solver. Due to this, the dynamic explicit calculation scheme was used instead, treating the case as quasi-static. This managed to produce enough usable results. It was concluded that the nonlinear finite element method is useable for assessment calculations, but that its strengths and weaknesses must be known in order to make it an efficient method.

Рассмотрены конструктивные и технологические решения по усилению изгибаемых железобетонных конструкций композитными материалами на основе углеродного волокна. Выявлены используемые системы для усиления железобетонных конструкций. Проведен сравнительный анализ существующих систем усиления на основе углеродных волокон. Определена экономическая эффективность такого способа усиления для изгибаемых железобетонных элементов. Приведена методика расчета усиления изгибаемых железобетонных элементов композитными материалами. Произведен расчет усиления различными композитными материалами на примере железобетонных элементов: балка, монолитная плита перекрытия. Выполнено сравнение различных вариантов усилений и предложен коэффициент условной полезности, позволяющий экономически обосновать выбор способа усиления и прогнозировать стоимость усиления конструкции. / Design and technological solutions for reinforcing of bending concrete structures with composite materials based on carbon fiber are considered. The used systems for strengthening reinforced concrete structures are re-vealed. A comparative analysis of existing reinforcement systems based on carbon fibers is carried out. The economic efficiency of this reinforcement method for bending concrete elements is determined. The calculation technique for bending concrete elements reinforced by composite materi-als is given. The calculation of reinforcement by various composite materials is made on the example of reinforced concrete elements: a beam and a monolithic floor slab. The comparison of various amplification variants is made and the conditional utility coefficient is proposed, which makes it possible to economically justify the choice of the gain method and to predict the cost of strengthening the structure.

No description available.

Environmental sustainability is becoming more popular in the building industry. Sustainable thinking needs to be present during the whole construction process, from the idea phase to the final stages. The aim of this master thesis is to investigate how end-bearing concrete and steel pipes as well as composite concrete-filled steel tube piles can be designed with greater consideration to climate impact. The purpose of this study is primarily to encourage awareness during the material choice phase in early stages of project planning. A Matlab code was programmed to perform a parametric study and analyze different parameters effect on pile bearing capacity. The structural bearing capacity of a number of different piles with various prerequisites were compiled in tables. The climate impact of the piles was expressed as global warming potential (GWP). In order to compare different pile types a functional unit was created as the ratio of the piles' bearing capacity and the corresponding climate impact. The ratio was calculated for all the piles and resulted in a number of figures with bearing capacity as a function of climate impact. These figures are supposed to be used as a basis to choose which pile type is most useful in a given situation. The usability of the results was verified with a calculation example. In the example, the figures were used to chose one pile out of several options as the most climate-efficient with the highest usage ratio. Finally, a number of general conclusions could be drawn regarding pile types. When the corrosion is small (<2 mm), it can be ascertained that steel pipes are to prefer over composite pipes. With larger corrosion (>2 mm), it can be ascertained that composite piles are preferable, specifically in cases were the soil is looser. However, in firmer soil, with undrained shear strength between 10-25 kPa, composite concrete-filled steel pipes are the better option. The results show that the contribution of the concrete to the bearing capacity of the composity files is minimal compared to the contribution of the decreased inner corrosion. This implies that it is more important to have the pipes filled with to prevent inner corrosion, rather than use a strong material that contributes to the bearing capacity. With that said, composite piles are not sustainable and different filling materials can be examined to further investigate whether there is another material with smaller climate impact that makes for piles with larger ratio of bearing capacity to climate impact. The main conclusion of the master thesis is that there needs to be a standardised approach to calculating climate impact from foundation construction and it should be included in a building's life cycle analysis (LCA). / Miljövänlighet och hållbarhet är begrepp som förekommer allt oftare i byggbranschen.Hållbarhetstänket behöver finnas med under hela byggprocessen, från idéfas till slutskede. Syftet med det här examensarbetet är att undersöka hur dimensionering av spetsburna betong- och stålrörspålar samt samverkanspålar kan utföras med större hänsyn till klimatpåverkan. Målet är framför allt att med hjälp av enklare klimatkalkyler främja klimatmedvetna materialval i tidig projektering. En parameterstudie som undersökte olika parametrars påverkan på pålens bärförmåga och klimatpåverkan utfördes i Matlab. Den strukturella bärförmågan hos ett antal olika pålar med olika förutsättningar som indata sammanställdes. Pålarnas klimatpåverkan uttrycktes i deras globala uppvärmningpotential (GWP) och för att kunna jämföra olika pålar med varandra skapades en gemensam funktionell enhet. Kvoten mellan pålarnas bärförmåga och motsvarande klimatpåverkan utgjorde den funktionella enheten. Kvoten beräknades för samtliga undersökta pålar och resulterade i ett antal figurer med bärförmåga som funktion av klimatpåverkan. Dessa figurer ska fungera som underlag vid bestämning av påltyp och användbarheten verifierades med ett beräkningsexempel. Med hjälp av de framtagna graferna gick det i beräkningsexemplet att välja ut pålen som var mest effektiv med hänsyn till klimatpåverkan och utnyttjandegrad av flera möjliga alternativ. Ett antal generella slutsatser gällande påltyp kunde dras. Vid små rostmåner (<2 mm) kan det konstateras att stålrörspålar är mer fördelaktiga än samverkanspålar. För resterande rostmåner (>2 mm) är samverkanspålar lämpligare i de fall där jorden är lösare. I fastare jordar med odränerad skjuvhållfasthet mellan 10-25 kPa är betongfyllda stålrörspålar utan samverkan ett bättre alternativ. Resultaten visar att det som ger störst effekt inte är betongens bidrag till bärförmågan utan det är minskningen av den inre rostmånen som har störst påverkan. Det innebär att det är viktigare att pålen är fylld än att den är fylld med något starkt som kan bidra med bärförmåga. Alltså är det inte hållbart att använda samverkanspålar och man kan vidare undersöka om det räcker att fylla med något klimatvänligare material som exempelvis cementbruk med lägre cementinnehåll och cementkvalité. Arbetets viktigaste slutsats är att det behövs en standardiserad beräkningsmetod för klimatpåverkan från grundläggning och att det bör ingå i byggnaders livscykelanalyser (LCA) eller klimatdeklarationer.

As the population increases, Swedish cities are becoming more urbanized. Consequently, people’s well-being deteriorates, and global warming has become reality. Buildings are replacing green spaces, necessitating the implementation of new methods to reintroduce greenery into urban areas. This study was conducted to investigate how a wall of an existing building in Halmstad, Sweden, is affected by supporting a living wall concerning load-bearing capacity, moisture, energy performance and economics. The methodology of this qualitative study includes literature review, interviews, and calculations for moisture, heat, and load-bearing capacity. The study found that living walls serve as additional insulation and that moisture does not affect the existing wall due to a vapor barrier. Also that the calculated wall withstands the weight of the living wall. Installation and maintenance costs can vary widely, and there is a wide range of plant species available. It's important to find plants that can withstand the climate for the specific wall. A broader selection of plants is available among those that wither in a beautiful way and are thus not evergreen. After interviews, it can be noted that living walls require minimal maintenance and thus maintenance costs are constant. Over time, some costs will be reduced as cooling and heating expenses decrease since the living wall acts as additional insulation.

No / Rectangular concrete-filled steel tube (CFST) may be subjected to local bearing forces transmitted from brace members while being used as a chord of a truss, and thus development of finite element analysis (FEA) and simple design calculation method for rectangular CFSTs under local bearing forces are very important to ensure the safety and reliable design of such a truss with rectangular CFST chords in engineering practices. A three-dimensional FEA model was developed using ABAQUS software package to predict the performance of thin-walled rectangular CFST under local bearing forces. The preciseness of the predicted results was evaluated by comparison with experimental results reported in the available literature. The comparison and analysis show that the predicted failure pattern, load versus deformation curves and bearing capacity of rectangular CFST under local bearing forces obtained from FEA modelling were generally in good agreement with the experimental observations. After the validation, the FEA model was adopted for the mechanism analysis of typical rectangular CFSTs under local bearing forces. Finally, based on the parametric analysis, simple design equations were proposed to be used to calculate the bearing capacity of rectangular CFST under local bearing forces. / National Natural Science Foundation of China (51421064) and the Natural Science Foundation of Liaoning Province (2013020125). The financial support is gratefully acknowledged.