Orientador: Pérsio Leister de Almeida Barros / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-22T04:55:08Z (GMT). No. of bitstreams: 1 Linhares_RaquelMariano_M.pdf: 5654140 bytes, checksum: 3419102ebbcf423e217e71ff2b761f76 (MD5) Previous issue date: 2013 / Resumo: No presente trabalho foram realizados ensaios em modelos físicos em escala reduzida de fundação rasa sobre solo arenoso fofo reforçado com geotêxtil tecido, visando avaliar o seu comportamento sob carregamento estático vertical. Propõe-se empregar o reforço numa posição inicial não-planar, semelhante àquela adquirida após deslocamentos de 30% da largura da base da sapata (B). Os efeitos da compactação das camadas superiores ao reforço e a variação de seu comprimento também são investigados. Os ensaios foram divididos em 3 grupos: ensaios sobre areia fofa com compacidade homogênea, ensaios de recarregamento e ensaios sobre areia fofa com camadas superiores compactadas. Os resultados indicam que um aumento do comprimento do reforço planar de 3B para 5B não é justificado do ponto de vista do aumento da capacidade de carga ou da atenuação de deslocamentos, em nenhum dos casos. A pequenos deslocamentos, a modificação do posicionamento inicial do reforço de horizontal para não-planar não se justifica, porém, em maiores deslocamentos há um ganho não desprezível na capacidade de carga. Os ensaios de recarregamento mostraram que a protensão do reforço resultante da compactação do solo melhora a capacidade de carga em 2 vezes e atenua em até 75% os deslocamentos. O posicionamento inicial referente a um deslocamento de 30% de B mostrou-se satisfatório; deslocamentos excedentes não trazem maior eficiência ao conjunto. O esforço de compactação gera ganhos similares na capacidade de carga independente do posicionamento inicial do reforço. A atenuação de deslocamentos pode chegar até a 2,6 vezes se comparada ao mesmo caso reforçado com areia homogênea / Abstract: In the present study, some small-scale model tests of a strip footing foundation on loose sand reinforced with woven geotextile were conducted. The main objective was to investigate the effect of the initial placement geometry of the reinforcement on the foundation response to static vertical loads. A non planar placement geometry similar to the one which results from a vertical displacement of about 30% of the foundation width was adopted. The effects of the top layers compaction and the variation of reinforcement length and initial placement were evaluated. The tests were separated in 3 groups: tests on loose sand with homogeneous compacity, reload tests and tests on loose sand with compacted top layers. Results show that an increase on reinforcement length from 3 to 5 times the footing width is not worth the increase in bearing capacity nor the attenuation of settlements, in none of the several cases studied. At little displacements, the modification of initial reinforcement placement, from horizontal to non-planar, seems not to be justified; although after some displacement there is a gain in the bearing capacity. The reload tests showed that the soil compaction creates a prestressing condition on the reinforcement, which improves the bearing capacity in about 2 times and attenuates the settlements up to 75%. The initial placement in about 30% of footing width displacement has proved to be satisfactory; greater displacements do not generate greater system efficiency. The compaction effort of the upper layers creates an improvement that doesn't depend on the reinforcement initial placement. The displacement attenuation can reach up to 2.6 times if compared with the same reinforced case in homogeneous sand ground / Mestrado / Geotecnia / Mestra em Engenharia Civil

In its theoretical part, the diploma thesis deals with the reasons leading to terrorist attacks and a brief list of some attacks on aircraft. It also focuses on the aircraft as the target of a terrorist attack, especially the aircraft kite as the major researched part. The conclusion of the theoretical part summarizes a list of types of aircraft fuselage structures in respect of design solutions for load transfer. The practical part determines the extent of damage caused by a missile with a fragmentation warhead. This scope is then applied to the illustrative case. In the following chapters, the calculation of the critical force of a panel loaded with pressure depends on the different nature and extent of damage. Then the work highlights the evaluation of the obtained results, which are also summarized in the conclusions of the work.

Master's thesis deals with the reinforcement and expansion of girder bridge (continuous bridge with three spans) across the river Jihlava in Ivančice and reinforcement on the load class A. This is done by using an additional external prestressing cables and composite monolithic slab. Amplification is verified by calculation of load capacity.

This master’s thesis is concerned with the static load capacity assessment of the reinforced concrete facility in the sports and recreational compound Kraví Hora in Brno, which is up to be reconstructed. The calculation results, overall assessment and static security suggestions are interpreted in the summary of the thesis.

The diploma thesis deals with inspection and construction technical survey of the reinforced concrete bridge structure and final evaluation of the condition of the selected reinforced concrete bridge object. This bridge structure is located on the road 4794 and overcomes the Olešná stream in the town of Paskov.

Content of this master's thesis is reconstruction of road brigre and determination of its load capacity before and after reconstruction.

This report presents the result of a Master thesis course done at the Machine Design department at KTH. The thesis was written at the company Svea Teknik in collaboration with the tunnel boring machine manufacturer Atlas Copco. The high longitudinal force needed when the Remote Vein Miner is boring is achieved by the friction when clamping the machine between the tunnels ceiling and ground using hydraulic cylinders mounted on the top and bottom of the machine. A new generation of machines doesn’t allow for the bottom cylinders to be fitted on the machine. The pair of continuous tracks used to propel the machine must bear these loads but the tracks aren’t strong enough to alone support the weight of the boring machine. This creates the need for an unloading system which unloads the inner wheels of the track so they don’t fail. Concepts were generated using a morphological matrix with the load sharing unit broken down to sub functions with several solutions paired to each. The iterative process led to nine concepts, where two proved more promising than the others when they were subjected to a Pugh’s evaluation matrix. The two concepts were developed further where a feasibility analysis indicated that only one concept was feasible with the dimensions given in a CAD model together with the load provided by Atlas Copco. The remaining concept is based on hydraulic cylinders lifting the inner wheels of the track to unload them while the machine is boring. The machine is then resting on a skid mounted inside the track. A CAD model was made of the new concept and the new components strength was analyzed using FEM-models. / I denna uppsats presenteras resultatet av ett examensarbete för masterprogrammet Maskinkonstruktion på KTH. Arbetet utfördes på förtaget Svea Teknik tillsammans med tunnelborrmaskintillverkaren Atlas Copco. De stora longitudinella krafterna som krävs när tunnelborrmaskiner borrar erhålls med hjälp av hydraulcylindrar monterade både på ovan- och undersidan av maskinen som klämmer fast maskinen mellan tunnelns golv och tak. En ny generation maskiner från Atlas Copco tillåter inte hydraulcylindrar monterade framtill på undersidan av maskinen. Istället tar de båda bandenheterna som är avsedd att driva maskinen framåt upp dessa krafter. Bandenheterna är inte tillräckligt starka för dessa laster utan en avlastningslösning för hjulen inne i bandenheten behövs. Problemet delades upp i subfunktioner som sattes in i en morfologisk matris för att generera koncept. Den iterativa processen ledde till nio koncept där två av dem visades mest lovade efter en konceptutvärdering med hjälp av en Pugh’s matris. De båda koncepten arbetades vidare till en mer detaljerad nivå där en rimlighetsanalys visade att endast ett koncept var fysiskt möjligt att applicera med de givna begräsningarna som gavs av utrymmet i den givna CAD-modellen tillsammans med de givna lasterna. Det kvarstående konceptet baseras på hydrauliska kolvar som monteras på hjulen i bandenheten. Dessa förflyttar hjulen uppåt tills de inte är i kontakt med bandenhetens kedja längre. Kedjan vilar då på en stödstruktur som är stark nog för lasterna. En CAD-modell gjordes på konceptet och de nya komponenternas hållfasthet analyserades med hjälp av FEM-modeller.

yes / Twenty two reinforced concrete continuous deep beams with openings and two companion solid deep beams were tested to failure. The main variables investigated were the configuration of web reinforcement around openings, location of openings, and shear span-to-overall depth ratio. The influence of web reinforcement on controlling diagonal crack width and load capacity of continuous deep beams with openings was significantly dependent on the location of openings. The development of diagonal crack width and load capacity of beams having openings within exterior shear spans were insensitive to the configuration of web reinforcement. However, for beams having openings within interior shear spans, inclined web reinforcement was the most effective type for controlling diagonal crack width and increasing load capacity. It has also observed that higher load and shear capacities were exhibited by beams with web reinforcement above and below openings than those with web reinforcement only above openings. The shear capacity at failed shear span of continuous beams tested is overestimated using Kong et al’s formula developed for simple deep beams with openings.

Yes / The current paper aimed at investigating the flexural performance of five large-scale continuous concrete beams reinforced by both steel bars and glass fibre reinforced polymer (GFRP). All the studied specimens had the same geometrical dimensions, with 200mm width, 300mm depth, and two identical spans of 2600mm. The quantity of longitudinal steel reinforcement, GFRP reinforcement, and hybrid reinforcement ratio at the top and bottom layers of beams were the key parameters explored in this study. The experimental findings indicated that using the hybrid reinforcement of steel and GFRP in multi-span continuous concrete beams exhibited a ductile behaviour. However, the hybrid ratio of steel bars/GFRP is critical for restricting the extent of moment redistribution ratios. Moreover, using the same hybrid reinforcement ratios at sagging and hogging regions led to a limited moment redistribution. On the other hand, the hybrid beams strengthened by various hybrid ratios in the critical sections of the tested beams demonstrated a remarkable moment redistribution up to 43%. The test results were compared with the available theoretical model and equations for predicting the beams’ moment capacity. It was found that the ACI.440.2R-08 reasonably predicted the flexural capacity of tested beams whereas the Yinghao and Yong equation underestimated the flexural capacity in the hogging sections. It was also shown that using the collapse mechanism with plastic hinges at sagging and hogging sections yielded good predictions for the loading capacity of hybrid reinforced concrete continuous beams.

Industrial forklifts consist of one of the most common handling methods for pallets in warehouses and distribution centers. Pallets deflect while they are being transported by forklifts due to the weight of the unit load. Thus, most of the deflection is observed to occur on the outside edges and corners of the pallet. Several international standards are used in order to define the maximum deflection for pallet bending, including ISO 8611 and ASTM D1185. However, there is still a lack of understanding on the accuracy of these deflection limits and the exact performance of a pallet during a forklift support condition. Understanding pallet bending during forklift support condition and how it affects the stability of a unit load helps create an industry accepted deflection limit that will help to design safer and more cost-effective pallets. For this study, two chapters were proposed in order to assess pallet deflection and unit load stability. The first chapter consisted of measuring and analyzing the vibration levels for three different industrial forklifts affect by factors such as the speed, the payload of the unit load carried, sensor location, forklift type, and road conditions. The results obtained showed that the highest vibration intensity occurred at 3-4 Hz, while the highest overall Grms value observed was 0.145 G2/Hz (between 1-200 Hz). An increase in the forklift speed caused an increase in vibration intensity. In contrast, an increase in the unit load weight carried by the forklift caused a decrease in vibration intensity. Among the three forklifts studied, the gas-powered forklift had the highest vibration intensity, and all forklifts, when driven on asphalt, experienced more vibration. The second chapter of the research project consisted of evaluating pallet deflection under forklift handling conditions. These conditions included fork tines configuration (leveled and 4° angle), unit load condition (bound and unbound), pallet orientation (across width and across length), and type of handling condition (static and dynamic). The results showed that when unit loads were handled in a static condition, they survived the throughout the entire testing. However, when they were tested under a dynamic condition, and specifically, with the unbound unit loads, they did not survive the entire testing. Moreover, unit loads that were tested with the 4° angle forktines configuration tended to survive longer during the dynamic testing. For this particular case, the unit load capacity obtained based on the ISO 8611 standard was too conservative. / M.S. / Forklifts play an important role in the transportation of materials goods in the supply chain. Pallets experience vibration when they are handled by industrial forklifts. This vibration plus the combined effects mainly due to the unit load weight affects the amount that pallets bend. Thus, depending on the amount of pallet bending, they can produce unit load instability. Currently, there is a lack of understanding of how much pallet bending is acceptable. Therefore, the goal of this research was to understand the behavior of pallet bending when they are handled under forklift conditions. Two experiments were conducted in order to study pallet deflection under forklift handling conditions. The first experiment, which consisted in analyzing forklift vibration, showed that an increase in the forklift speed caused an increase in vibration intensity. In contrast, an increase in the payload of the unit load resulted in a decrease in vibration intensity. Among the three forklifts studied, the gas-powered forklift showed the highest vibration intensity. Forklifts driven on asphalt experienced more vibration in comparison to the ones driven on concrete. The second experiment, which consisted in assessing pallet deflection under a simulated forklift handling condition, showed that unit loads under a dynamic environment (vibration) increased the probability of unit load instability. Furthermore, it was observed that applying stretch wrap to a unit load decreased its instability and at the same time increases its survivability. Also, the results showed that the proposed ISO 8611 deflection limit is too conservative for this particular handling condition.