155 resultados para concreto com fibras


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Pós-graduação em Engenharia Civil - FEIS

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Engenharia Mecânica - FEG

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This work presents a fast, easy, standardized and planned method to build family homes in order to collaborate with the decline of housing deficit and, at the same time, meet families who wish to invest in building their own houses, once that our country is experiencing an economical prosperity . This method has been widely used nowadays because it is being deployed in large-scale and in a standardized pattern, reducing decreasing significantly the construction time. The concrete wall, shaped in loco depends on unique processes. For this reason, a well trained staff is required so the constructive process can be executed in a fast pace, showing better results than other construction methods. This project will address all the materials used to build the molded concrete walls in loco, their sequence assembly, application, types, characteristics and performances. At the end, a way used by building companies of locating the concrete will also be given. Although there is no specific Brazilian norm for this type of construction, a study on this topic will soon be released. Therefore, the studies for the execution of this project were based on Brazilian standards prevailing at the time, construction magazines and books that are based on building methods considered more common

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The change in design of a building can occur during its construction process, especially when this change involves greater amount of profit for the building company, as it is the case of adding extra floors. However, there must be an analysis of the structure of the building in order to see if it is possible to increase the number of floors without the need of reinforcement, as this need would result in higher costs for the building company. This graduation report presents this analysis by using the methods of third order verification of reinforced concrete structures

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The concern with the environment preservation has done with that researchers as well as industries invest in the search for materials that come from renewable sources. Natural fibers, because they are ecologically correct and have low cost, have been studied as a possible substitute, even if partial, of synthetic fibers in the development of polymeric composites. In this context, the hybrid composites (natural/synthetic) increase considerably the range of application of natural composites. The auto industry, in its constant quest for good mechanical properties materials which are developed with sustainability, has in composites with hybrid reinforcement a very viable alternative. In the present work, the nature Crown pineapple fibers and nature Crown pineapple fibers treated with alkaline solution were studied in order to evaluate the influence of chemical treatment in its properties. For this techniques were used x-ray diffractometry, Thermogravimetry and Infrared Spectroscopy (FTIR). Composites have been developed using polypropylene, reinforced with pineapple fibers and pineapple fibers hybrids/glass fibres, both with levels of 5 and 10%. These composites were analyzed by Thermogravimetry techniques and tested by traction. The realization of this work indicated that although the chemical treatment did not affect the thermal stability of the fibers, caused an increase in crystallinity index fibers and decreased its hydrophilic. The tests performed on composite indicated that the composites process was suitable because it provided good dispersion of the polymer matrix. The addition of natural fibers from the pineapple's Crown, in a proportion of 10%, provided the greatest increase in modulus of elasticity (27%) when compared to the pure polymer

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In civil engineering, a structure is the whole sustainment of a construction and, thus, it is important that it remains intact throughout its lifetime. An engineering construction must last for decades without losing its functionality. However its purpose may be altered and several times the original structure does not meet the new needs of use. Still, in new buildings, the functionality is altered due to possible flaws in execution and the structure, invariably does not reach the desired solicitation needs. In cases like this, the commonly adopted solutions are, basically, the demolishment followed by the reconstruction of the desired mold or the structural reinforcement. This second option, for long years, has not been put to practice due to certain factors such as the high costs for its implantation, use of inadequate reinforcement execution techniques, and the culture of people involved in the area regarding its use and, in this case, the option would always be the reconstruction. Thoughtout the years, some techniques were developed to allow the execution of structural reinforcements with low costs and in efficient ways. An interesting, fast, efficient and economical technique is the structural reinforcement through metal sheets put together with epoxy resin that can be applied in beams, slabs and pillars. In the present work the different behavior of beams reinforced with this technique. Steel is a very recommended material for these reinforcements due to its characteristics related to traction, compression and the effectiveness of the technique related to its cost. For the attachment the epoxy resin is recommended, since it allows the joining of two materials, in this case, steel and concrete. The efficiency of this union is so considerably high that it rarely produces any flaws in adherence and, normally, when it happens it is due to problems in the execution process, not in the union of materials

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Are being released in the construction market in Brazil ventures called Super 6. These businesses sell the promise of delivery of the apartment in six months after the launch of the venture. To meet this deadline are being deployed the constructive method of concrete walls using aluminum shapes. This system basically consists of pouring slabs and walls once, i.e. building up the wall shapes and slab joints. On the walls are used cloth, with reinforcements in vain and corners of walls and on these screens are tied the electrical boxes and conduits. For each tower is used the so-called system of half way, i.e. the system so it is sufficient to mount the Middle deck. Using a concrete which can be deformed in the next day you can lift one deck every two days with ready electric and hydraulicsystem, without having to tow the wall doing only minor fixes in the imperfections after concrete. With this system won an incredible speed in the construction of the structure reducing in almost one-third the length of the work. This work aims to compare in terms of cost-benefit of masonry structural systems and this new concrete wall system called Super 6. For this comparison will be used as parameter values used for the achievement of the Enterprise Portal of Roses of constructor Tenda which is one of the first to use concrete wall system. This project basically consists of seven towers of six floors each and will be budgeted the cost of this project if it were held in structural masonry. From these data it will be possible to make a comparison about the actual beneficial to adopt this system

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It aims the comparison of these moments between an analytical plates theory and a computational numerical simulation. It is accented the details of studies about analytical theory as well the process, step by step, of a program that has as an influence the method of finite elements. The theory of plates has an extremely importance when it is talked about slabs and it takes as a base some fundamental hypotheses (that the middle point of the plate is considered flat and under formable) the points that are normal in relation to the middle surface is not considered because of its intensity that is irrelevant in comparison to the rest. The computational programs offer good results when they are applied in a correct way and, it resolves numerous functions in a short period of time. The objective is to highlight the importance of bending moments, its points of maximum and minimum, that has the objective of realize a good reinforcement sizing for a reinforced concrete. Furthermore, it can propitiate an economy in places that is demanded a small quantity of steel, before dimensioned for a load that is distributed in all the surface of the plate, at the same intensity

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After confirming the high specific mechanical properties of composite materials by scientific studies conducted over the last decades, one of the challenges of this new class of materials is the ability to achieve mass production at a more affordable cost, which has become indispensable. The Resin Transfer Molding (RTM) is an excellent method for manufacturing composite materials. Despite being a process widely used by international companies in the production of high performance structural composites, only a short time the national aviation industry has shown interest in implementing this type of processing to more complex structures and greater structural responsibility. In aeronautical projects, the reproducibility and the relative low cost of this process, several studies have been performed in Brazil for learning and perfecting this technique. This process is suitable for producing polymer components both simple as complex geometry, and allows to achieve consistent thickness, with high quality finish and without limiting range. Polymeric composite components for the high mechanical stress applications such as aircraft structures, satellites, etc., require a strict control of volume fractions of the composite constituents, beyond the knowledge of their mechanical and thermal properties. Therefore, in this experimental work degree study on the mechanical, thermal and of porosity composites processed by RTM processed characterization was performed. This characterization was performed targeting a possible aerospace application of this composite material. For the production of composites, process equipment (RTM RTM injector Radius 2100cc) was used. The processed carbono/epoxy composites were characterized via flexure tests mechanically and thermally analysis via DMA, DSC and TGA. To determine the volume fraction of fibers, the composite samples were analyzed via matrix digestion (ASTM D3171) ... (Complete abstract click electronic access below)

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The growth of urban population associated with the shortage of supply of public infrastructure such as hospitals, kindergartens, schools, among others, has reinforced the need to develop alternative methods that simplify the construction processes and allows for a reduction in these costs works. The conventional processes have increasingly been shown ineffective to solve the problem of demand for different types of urban and rural buildings. Given this fact, industrial construction processes can gain space and have proven to be highly interesting to solve the above problems, in particular, considering the cost-effective and time. Therefore, this study aimed to determine the influence of moisture on the strength of metal plate connections connectors (printed plate with teeth). For the sizing of the links between structural lumber using metal connectors with teeth prints; controlled process variables (drying of the wood and the different moisture contents), and finally found results and compare them with different literatures order to obtain a qualitative efficiency of the process. Some specimens had very low expectations, can be explained by the presence of bone marrow, and pre-existing cracks. Thus, the results were discarded for further analysis and more accurate results