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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Análise ergonômica do trabalho na execução de armaduras

Carvalho, Laísa Cristina 20 May 2016 (has links)
Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2016-10-17T11:18:42Z No. of bitstreams: 1 DissLCC.pdf: 9084435 bytes, checksum: da33f0c1a0e3d47fafd347db42d4d2dc (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-21T13:59:01Z (GMT) No. of bitstreams: 1 DissLCC.pdf: 9084435 bytes, checksum: da33f0c1a0e3d47fafd347db42d4d2dc (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-21T13:59:07Z (GMT) No. of bitstreams: 1 DissLCC.pdf: 9084435 bytes, checksum: da33f0c1a0e3d47fafd347db42d4d2dc (MD5) / Made available in DSpace on 2016-10-21T13:59:13Z (GMT). No. of bitstreams: 1 DissLCC.pdf: 9084435 bytes, checksum: da33f0c1a0e3d47fafd347db42d4d2dc (MD5) Previous issue date: 2016-05-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Financiadora de Estudos e Projetos (FINEP) / Civil construction is one of the activities that generates most jobs in the country, owning handmade construction methods and with few technological innovations. It notes that the number of workers in that area is significant because of the diversity of existing activities in a building. In the case of the reinforcing steel service, tasks are performed manually and request different degrees of effort, which when applied recursively, with tools and equipment unsuitable and inadequate workplace, may cause damage to the health and comfort of workers. In this context, this study aims to evaluate the ergonomic working conditions of the reinforcing steel service. Therefore, we used the methodology of the Ergonomic Assessment Method for Task Analysis (AET), aided by three ergonomic tools: Ergonomic Workplace Analysis (EWA), the Metabolic Equivalent of Task (MET) and the Occupational Repetitive Actions (OCRA). Considering these factors analyzed, with photographic records, interviews and site visiting to watch the worker during his tasks, the actual conditions of the job were studied, trying to analyze everyday work situations, health and safety of workers and featuring, thus, the workplace conditions during reinforcing steel service. The results corroborate the existence of working inadequate postures while performing the task. According to ergonomic tool EWA the most critical ergonomic factor detected was related to Working Postures and Movement, followed by Load Lifting factor. Among the activities analyzed using this ergonomic analysis instrument, the one which presented more critic was related to the assembly of reinforcement for beams. According to the ergonomic analysis instrument MET, tasks with higher energy expenditure and metabolic expenditure were related to Receiving and Storage of steel bars. Among the operation inherent to each task of reinforcement service, there is the tie bars with annealed wire. Finally, it is concluded that the index of exposure OCRA for the activity of tie bars with annealed wire presents imminent risk to all analyzed situations. / A construção civil é uma das atividades que mais gera empregos no país, possuindo métodos construtivos tradicionais e com poucas inovações tecnológicas. Cabe ressaltar que a quantidade de trabalhadores nessa área é bastante significativa, devido à diversidade de atividades existentes em uma edificação. No caso do serviço de armação, as tarefas são executadas, em sua maioria, manualmente e solicitam diferentes graus de esforços que, quando aplicados de modo recorrente, com ferramentas e equipamentos impróprios e postos de trabalho inadequados, podem causar danos à saúde e ao conforto do trabalhador. Neste contexto, este trabalho tem por objetivo avaliar as condições ergonômicas do trabalho no serviço de armação. Para tanto, empregou-se a metodologia da Análise Ergonômica do Trabalho (AET), auxiliada por três instrumentos de análise ergonômica: Ergonomic Workplace Analysis (EWA), o Equivalente Metabólico (MET) e o Occupational Repetitive Actions (OCRA). Considerando tais fatores analisados, com registros fotográficos, entrevistas e acompanhamentos, foram estudadas as reais condições do posto de trabalho, buscando analisar as situações cotidianas de trabalho, saúde e segurança dos trabalhadores e caracterizando, assim, as condições do posto de trabalho durante o serviço de armação. Os resultados encontrados corroboram a existência de posturas inadequadas de trabalho durante a execução da tarefa. De acordo com o instrumento ergonômico EWA o fator ergonômico mais crítico detectado foi relacionado a Posturas de Trabalho e Movimentos, seguido pelo fator Levantamento de Carga. Dentre as atividades analisadas utilizando este instrumento ergonômico, a que se apresentou mais crítica foi a relacionada à montagem das armaduras para as vigas. De acordo com o instrumento de análise ergonômica MET, as tarefas com maior gasto energético ou gasto metabólico foram as relacionadas ao Recebimento e Estocagem das barras de aço. Entre as operações inerentes a cada tarefa do serviço de armação, destaca-se o amarre das barras com arame recozido. Finalmente, conclui-se que o índice de exposição OCRA para a atividade de amarre das barras com arame recozido apresenta risco iminente para todas as situações analisadas.
2

Effektivisering av armeringsprocessen med hjälp av Lean-metodik / Streamlining the reinforcement process using Lean methodology

Kleczkowski, Kim January 2022 (has links)
Detta examensarbete utgör den avslutande delen i högskoleingenjörsprogrammet inom maskinteknik på Kungliga Tekniska Högskolan med inriktningen industriell ekonomi och produktion och bedrevs i samarbete med Skanska Sverige AB. Studien undersöker hur Lean kan användas för effektivisering av armeringsprocessen av en stödmur genom att tillämpa Kata-metodiken adapterad för byggindustrins kontext. Det huvudsakliga målet med studien var att undersöka hur kostnadsbesparingar skulle kunna uppnås med hjälp av processförbättringar som minskar ledtiden för armeringsprocessen genom att ta fram ett måltillstånd för hur systemet bör fungera i framtiden. För att nå fram till målet med examensarbetet används en anpassad förbättringsmodell, Skanska Process Improvement (SPI) som steg-för-steg visar hur processförbättringar kan uppnås med hjälp av Lean-principer som exempelvis Genchi Gembutsu och PDCA. Vid genomförandet av studien har datainsamling till största del skett genom att följa yrkesarbetarna ute på arbetsplatsen under fem arbetsdagar vid progressionen av armeringsprocessen, vilket har genererat flertalet tidsadderande observationer. Tre måltillstånd har därefter tagits fram med syftet att eliminera avvikelserna varefter ett av måltillstånden valdes ut som lämpligast att bearbeta först, vilken är att implementera en standardiserad monteringsanvisning för armeringsprocessen. I ett längre perspektiv skulle SPI-modellen kunnat tillämpas för att förbättra helt andra byggprocesser som till exempel formsättning eller gjutning. För fortsatta studier skulle måltillståndet behöva omsättas i verkligheten genom utförandet av de PDCA-experiment som har förberetts i examensarbetet och med vägledning av SPI-modellen. / This bachelor thesis is the final part of the university engineering program in mechanical engineering at the Royal Institute of Technology with a focus on industrial economics and production and was conducted in collaboration with Skanska Sverige AB. The study examines how Lean can be used to streamline the reinforcement process of a retaining wall by applying the Kata methodology adapted to the context of the construction industry. The main goal of the study was to investigate how cost savings could be achieved with the help of process improvements that reduce the lead time for the reinforcement process by developing a target condition for how the system should work in the future. To achieve the goal of the bachelor thesis, a customized improvement model is used, Skanska Process Improvement (SPI), which step-by-step shows how process improvements can be achieved with the help of Lean principles such as Genchi Gembutsu and PDCA. In conducting the study, data collection has largely taken place by following the construction workers out in the workplace for five working days during the progression of the reinforcement process, which has generated several time-adding observations. Three target conditions have subsequently been developed with the aim of eliminating the deviations, after which one of the target conditions was selected as most suitable to process first, which is to implement a standardized assembly instruction for the reinforcement process. In a longer perspective, the SPI model could be applied to improve completely different construction processes such as formwork or casting. For further studies, the target condition would need to be tested in real world performing the PDCA experiments that have been prepared in the bachelor thesis and with guidance from the SPI model.
3

Coupled Resonant Coil Sensors for Remote Passive Monitoring Applications

Bhadra, Sharmistha 10 September 2010 (has links)
The thesis describes development and application of coupled resonant coil sensors, which is of growing interest for remote monitoring applications. An interrogation technique, which improves the accuracy and interrogation range of coupled resonant coil sensors, is introduced. The method uses time-domain gating to produce measurements that are dominated by the response of the sensor coil and are immune to surrounding object interference. For application in structural health monitoring a low cost embeddable coupled coil sensor, which is able to monitor the corrosion potential of reinforcement steel is presented. Results of an accelerated corrosion test using the sensor indicate that corrosion potential can be monitored with a resolution less than 10 mV and a sensitivity of 0.76 kHz/mV. The last part describes a coupled-coil pH sensor based on pH electrode potential measurement. A linear response over a 4 to 10 pH dynamic range and 50 kHz/pH sensitivity are achieved with a 0.1 pH resolution and 30 s response time.
4

Coupled Resonant Coil Sensors for Remote Passive Monitoring Applications

Bhadra, Sharmistha 10 September 2010 (has links)
The thesis describes development and application of coupled resonant coil sensors, which is of growing interest for remote monitoring applications. An interrogation technique, which improves the accuracy and interrogation range of coupled resonant coil sensors, is introduced. The method uses time-domain gating to produce measurements that are dominated by the response of the sensor coil and are immune to surrounding object interference. For application in structural health monitoring a low cost embeddable coupled coil sensor, which is able to monitor the corrosion potential of reinforcement steel is presented. Results of an accelerated corrosion test using the sensor indicate that corrosion potential can be monitored with a resolution less than 10 mV and a sensitivity of 0.76 kHz/mV. The last part describes a coupled-coil pH sensor based on pH electrode potential measurement. A linear response over a 4 to 10 pH dynamic range and 50 kHz/pH sensitivity are achieved with a 0.1 pH resolution and 30 s response time.
5

The climate impact of fishways : A life cycle assessment of Blyberg’s and Spjutmo’s up- and downstream fishways

Lundin, Ellen, Liljenberg, Lovisa January 2023 (has links)
The Swedish national plan for reapproval of hydropower describes that hydropower plants (HPPs) are required to be reassessed to ensure that modern environmental conditions are set for the permits. Since dams and HPPs create barriers for migrating fish and consequently disfavor biological diversity, one consequence of the national plan is that fishways are being constructed. This, in combination with an old, unfinished approval procedure from the 1960’s, resulted in the construction of three up- and downstream fishways in Mora municipality, at the HPPs in Spjutmo, Blyberg and Väsa. To fulfill requirements in regard to the fishway’s incline and safety, but at the same time minimize the need of space, the fishways have new, innovative and not yet tested design features. One of these features is the “parking garage” layout of the upstream fishway. Despite these features, the fishways take up a large amount of space and thus require large amounts of blasting, excavation and materials such as concrete and steel parts. These are climate impact influence intensive procedures and materials, but the construction has so far not been evaluated from a climate impact perspective. This, in combination with a lack of studies on the climate impact of fishways, has resulted in this project.The aim of this project was to examine the climate impact caused by the fishways in Spjutmo and Blyberg, to identify what affects the total climate impact as well as providing measures that could reduce the climate impact for future similar fishways. To provide an extensive overview of the climate impact that the fishways cause during their entire lifetime, the method life cycle analysis (LCA) was used. The construction of the fishways at Väsa HPP starts later than for Spjutmo and Blyberg, and therefore Väsa is excluded from the scope due to the lack of required information.The fishways in Spjutmo and Blyberg have the same design features, but the material consumptions differ due to their differences in head. Spjutmo’s head is 21,4 meter and Blyberg’s is 11 meter. A larger head generally results in a longer fishway which in turn results in a more material consuming construction. This resulted in the total life cycle climate impact being twice as big for Spjutmo as for Blyberg, 2 807 tonne CO2-eq respectively 1 361 tonne CO2-eq. The resource extraction is the LCA- phase that contributes the most. Concrete and its reinforcement have the biggest share of that impact, followed by mechanical parts and other steel products, road construction process in Spjutmo and the excavation process in Blyberg. Based on this result, it can be concluded that the materials and components contribute more to the fishways’ total climate impact, rather than processes. Roughly 80 % of the total climate impact origins from the upstream fishway, while the rest either stems from the downstream fishway or others. Sensitivity analyses include the climate impact caused by the fishways using some water that otherwise could have been used to generate electricity from, and the result indicates that all examined alternative energy sources would result in larger climate impact compared to if the electricity was generated by hydropower.One of the result’s uncertainties is that the fishways were under construction while this project was performed. Therefore some assumptions was made to compensate for lack of data. For example, the future electricity consumption was scaled up based off the then used electricity data. However, even if some amounts of required materials and processes changed as time went by, the changes did not make a significant difference from the bigger perspective. Sensitivity analyses that examined the climate impact of a delay in the construction also showed that the processes that are most likely to continue turned out to have a relatively small climate impact. Thus, this issue might not be as problematic as initially thought.Although the result is presented in total values, the result is also provided per a functional unit (FU) level in accordance with traditional LCA methodology. This was to facilitate a comparison for future LCAs on other fishways. The FU in this project was decided to be “One meter head for a technical, stationary, up- and downstream fishway in connection to a medium or large run-of-river hydropower plant in a cold tempered climate zone”. For future studies, LCAs on different types of fishways using the proposed FU is recommended.
6

Využití moderních kompozitních materiálů při návrhu betonových konstrukcí / The use of advanced composite materials for the design of concrete structures

Macháček, Jan January 2019 (has links)
The diploma thesis deals with the design of concrete structures reinforced by FRP according to ACI, fib, CSA and EC2 regulations, which are stressed by a shear force. The diferences between steel rebar and FRP reinforcement were described, in particular its mechanical degradation over time and a different stress-strain diagram. Furthermore, shear capacity calculations were performed according to the regulations and compared with the real tests. Then the parametric analysis of shear strength was performed. In the practical part, the design of concrete floor slab structure supported by the pillars and walls was performed. The upper reinforcement of this slab was designed with FRP and the lower with steel rebar. Double-headed studs were used as a punching shear reinforcement.

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