RESUMEN La construcción con estructura de acero es una opción interesante a la ya establecida estructura de hormigón en un momento en que la construcción civil brasileña busca más eficiencia. Para incentivar el uso de este material, es necesario conocer mejor sus características y, especialmente, sus posibles patologías, para evitar la degradación, los costes e incluso el colapso de la estructura. En este estudio se aplican las herramientas de Gestión de la Calidad Total al análisis de las patologías presentes en cinco edificios de estructura metálica de mediano y gran tamaño. Con la información sobre las patologías de estos edificios, se identifican los elementos causantes y se realiza el análisis de riesgo de las patologías utilizando, especialmente, el Diagrama de Ishikawa y la Matriz GUT. Las patologías más frecuentes destacadas en el estudio son la corrosión en la estructura, las grietas en los cierres y las infiltraciones en la interfaz cierre/ estructura. Las principales causas, según el diagrama de Ishikawa y la matriz GUT, están relacionadas con la técnica constructiva, la mano de obra, las condiciones ambientales y la materia prima utilizada. Los resultados obtenidos muestran que es posible, a través de las herramientas de Gestión de la Calidad, establecer el riesgo de cada patología, su origen y determinar el grado de riesgo que ofrece cada una.

ABSTRACT Structured steel construction is an interesting option to the already established concrete structure at a time when Brazilian civil construction seeks more efficiency. Encouraging the use of this material requires a better understanding of its characteristics and especially its possible pathologies to prevent degradation, costs, and even structural collapse. This study uses Total Quality Management tools are applied to analyze the pathologies present in five medium and large steel-structured buildings. The causative elements are identified with the information about the buildings' pathologies, and the risk analysis of the pathologies is performed using, especially, the Ishikawa Diagram and the GUT Matrix. The most frequent pathologies highlighted in the study are corrosion in the structure, cracks in the closures, and infiltrations in the interface closure/structure. The main causes, according to the Ishikawa diagram and the GUT matrix, are related to construction technique, labor, environmental conditions, and raw material used. The results show that it is possible, through the tools of Quality Management, to establish the risk of each pathology and its origin and determine the degree of risk that each one offers.

Abstract The use of steel in construction is an alternative that has changed the panorama of this sector, contributing to an increase in productivity, and a reduction in waste and construction time. The Light Steel Framing (LSF) system, introduced in Brazil at the end of the 1990s, is undergoing a process of technical development and acceptance in the national civil construction market, but there are still shortcomings regarding the design, itemization and implementation of the complementary closing systems, and also regarding its thermal performance. This study employs an analytical approach that uses the isothermal planes method to calculate the resistance and thermal transmittance, and a numerical approach that uses the ANSYS software (version 15) to verify and compare these analyses. Multi-layer closures are considered, with the outer layer being made up of cement board and the inner layer of gypsum board, brokered by fiber glass insulation and air, with studs formed by C-section profiles in galvanized steel. The isothermal planes method revealed the value of 0.77 (m2.K)/W for the equivalent thermal resistance, 1.3 W/(m2.K) for the thermal transmittance, and 13.04 W/m2 for the heat conduction flux. The difference of the results when comparing the isothermal planes and numerical solution methods was 9% for thermal resistance and 8% for heat conduction flux. The obtained results showed that the heat flux is equivalent to a value around 54% greater than the heat flux value for a closure without the presence of steel profile.

resumo: As edificações públicas de ensino necessitam de um planejamento para a conservação e manutenção de seus diversos sistemas e instalações. Na prática, constata-se que existem grandes desafios na gestão da manutenção das Universidades Federais do Estado de Minas Gerais que envolvem a falta de recurso financeiro, mão de obra desqualificada e insuficiente, falta de investimento no setor de Tecnologia da Informação específico para esse fim, ausência de plano ou programa de manutenção, ausência de ações específicas na manutenção de construções estruturadas em aço, ausência de equipe técnica para elaboração de vistorias, laudos e memorial, entre outros. Diante dessa realidade preocupante, o presente estudo visa a propor diretrizes de manutenção para as edificações de instituições de ensino públicas, afim de melhorar a qualidade da manutenção desses edifícios. A abordagem metodológica adotada é o estudo de caso exploratório. É realizada uma investigação das 11 instituições de ensino públicas de Minas Gerais. As principais contribuições do trabalho referem-se à proposição de diretrizes de gestão da manutenção como por exemplo, o conhecimento das edificações, o gerenciamento por meio de software e o programa de manutenção, a serem utilizadas e replicadas para outras instituições de ensino de semelhantes características.

abstract: Public education buildings require a plan for the conservation and maintenance of its various systems and facilities. In practice, it can be seen that there are major challenges in managing the maintenance of the Federal Universities in Minas Gerais State involving a lack of financial resources, disqualified and insufficient workforce, lack of investment in the Information Technology sector specific for this purpose, absence of a plan or program for maintenance, absence of specific actions in maintaining structured steel constructions, lack of technical staff for the preparation of inspections, reports and memorial, among others. Faced with this disturbing reality, this study aims to propose guidelines for maintenance of the buildings of public educational institutions, in order to improve the quality of maintenance of these buildings. The methodological approach adopted is the exploratory case study. An investigation of 11 public educational institutions of Minas Gerais is performed. The main contributions of the work refer to the proposition of maintenance management guidelines such as the knowledge of the buildings, the management through software and maintenance program to be used and replicated for other educational institutions of similar characteristics.

ABSTRACT Among the several factors that interfere with the thermal performance of buildings, soil temperature is not always considered in thermal performance evaluations. However, soil temperature is a factor that influences the result of heat exchanges in the environment, especially in ground-level buildings. Thus, it is necessary to evaluate this influence due to the interaction of the soil with the building. In addition, due to the three-dimensional and transient character of the heat exchange processes involving the ground, the numerical approach becomes an important tool in the thermal performance analysis of buildings. In this respect, the software EnergyPlus emerges as an alternative to obtain such results, especially through the Basement preprocessor. Results suggest that, when the soil effect is considered in thermal analyses, the internal temperature of subterranean rooms increases up to 8.9% in the summer and decreases to 5.4% in winter. These results were obtained when compared to the initial situation, where soil influence had been neglected. Such results provide an indication of the importance of considering the soil influence on the thermal performance analyses where an accurate assessment is requested.

RESUMEN Entre los diversos factores que interfieren en el desempeño térmico de las edificaciones, la temperatura del suelo no siempre es considerada en las evaluaciones de desempeño térmico. Sin embargo, la temperatura del suelo es un factor que influye en el resultado final de los cambios de calor de los ambientes, principalmente en edificaciones térreas. De esta forma, se hace necesario evaluar dicha influencia debido a la interacción del suelo con la fundación y paredes de una edificación. Además, en función del carácter tridimensional y transitorio de los procesos de intercambio de calor envolviendo el suelo y las paredes subterráneas, el abordaje numérico se convierte en una herramienta importante en el análisis del desempeño térmico de las edificaciones. En este sentido, EnergyPlus figura como un software de simulación de carga térmica y desempeño energético de edificaciones y surge como una alternativa para la obtención de dichos resultados, sobre todo a través delpreprocesador Basement. Los resultados indican que, cuando el efecto del suelo es considerado en los análisis térmicos de edificación, la temperatura interna de las habitaciones subterráneas se eleva hasta un 8,9% en el verano, y se reduce hasta un 5,3% en el invierno. Estos resultados se han obtenido comparando la situación inicial, donde la influencia del suelo no era tomada en cuenta. Estos datos proporcionan indicaciones de la importancia de la consideración de la influencia del suelo en los análisis de desempeño térmico, donde se solicita una evaluación precisa.

Resumo A temperatura do solo é um dos fatores mais influentes nas avaliações de desempenho térmico de ambientes subterrâneos e quase sempre é desconsiderada. Por isso, é necessário avaliar essa influência devido à interação do solo com a edificação, pois a transferência de calor através de paredes e pisos subterrâneos tem uma extensão significativa na carga térmica total de uma edificação. Este trabalho compara e avalia o impacto de diferentes alternativas de modelagem presentes no programa de simulação EnergyPlus por meio da análise das trocas de calor entre o solo, o piso e as paredes de um ambiente subterrâneo de uma edificação unifamiliar de São Paulo, Brasil, não condicionada artificialmente e não isolada termicamente. A comparação das alternativas de modelagem por meio da análise recomendada pela NBR 15575 indicou grande variação nos resultados de temperatura interna do ambiente subterrâneo da edificação. Quando comparado ao pré-processador Basement, os modelos do objeto GroundDomain apresentaram variação de temperatura interna do ambiente subterrâneo de até 6 ºC no verão e de 5,2 ºC no inverno. Tais resultados fornecem indicações da influência e da variabilidade que o uso das diferentes opções de modelagem do EnergyPlus podem gerar em uma análise de desempenho térmico.

Abstract Soil temperature is one of the most influential factors in the evaluation of the thermal performance of underground environments, but it is almost always disregarded. Thus, it is necessary to evaluate this influence due to the interaction of the soil with the building, since heat transfer through subterranean walls and floors has a significant extension in the total thermal load of a building. This study compares and evaluates the impact of different modelling alternatives present in the EnergyPlus simulation program by analysing the heat exchanges between the soil, the floor and the walls of a basement of a single-story building in São Paulo, Brazil, not artificially conditioned and not insulated thermally. The comparison between the modelling alternatives through the analysis recommended by NBR 15575 indicated a large variation in the internal temperature results of the underground building environment. When compared with Basement pre-processor, the models of the object GroundDomain presented an internal temperature variation of the basement up to 6 ºC in the summer and up to 5.2 ºC in the winter. These results offer indications of the influence and variability that the use of the different modelling options present in EnergyPlus program can generate in a thermal performance analysis.

Resumo A análise da relação entre conforto térmico e as condições climáticas de determinada localidade pode ser uma importante ferramenta de planejamento urbano. Uma das formas de avaliação é a utilização de índices de conforto, como, por exemplo, o PET (Physiological Equivalent Temperature), índice amplamente utilizado em estudos de conforto térmico em espaços abertos, contudo apenas após a devida calibração às preferências térmicas da população local. Este trabalho teve como objetivo apresentar uma calibração do índice PET para Curitiba, PR, cidade de clima temperado de altitude (Cfb), por três procedimentos distintos. Os dados climáticos e subjetivos foram obtidos em campanhas de monitoramento térmico entre 2009 e 2010, que abrangeram verão, outono e inverno. Para a calibração, foram utilizados três métodos, notadamente: (a) agrupamento dos votos de percepção térmica a partir de entrevistados para variações discretas de 1 ºC na escala PET; (b) identificação de categorias mais frequentes para votos agrupados de percepção térmica, por mesma variação de grau PET; e (c) método das curvas Probit. O segundo método foi considerado pouco preciso na definição dos limites para Curitiba, enquanto o método Probit gerou resultados semelhantes aos obtidos pelo primeiro método, a partir dos quais foi estabelecida uma faixa de conforto térmico para espaços externos.

Abstract The analysis of the relationship between thermal comfort and the climatic conditions of a given location can be an important tool for urban planning. A possible way to perform such evaluation is by means of comfort indices, such as PET (Physiological Equivalent Temperature), which is widely used in thermal studies in open-air environments, after duly calibration to local thermal preferences. This study aims to calibrate the PET index for Curitiba, a city characterized by a temperate climate (Cfb), according to three distinct procedures. Climatic and subjective data were obtained in outdoor thermal monitoring campaigns during 2009 and 2010, covering summer, autumn and winter. Calibration procedures involved three distinct methods: 1) binning method for 1 ºC discrete variations in the PET scale; 2) identifying the most prevailing thermal sensation categories in each 1 ºC PET-bin; 3) Probit analysis. Method 2 was considered less precise in defining limits for Curitiba while Probit results corresponded well with those from Method 1, by which a comfort zone for outdoor spaces was obtained.

Abstract This article provides an evaluation of the acoustical and thermal performance of some closing systems by referencing materials such as cement plates, plasterboard walls, precast concrete panels and expanded polystyrene. Reverberation time is calculated by applying an empirical formula, which uses temperature and relative air humidity values obtained from simulations that were conducted using the computational simulation program ESP-r (Energy Simulation Program-research). The internal temperature presented by the ESP-r is an indicator of thermal performance. Using a simplified graphic method, the acoustical performance is also evaluated by estimating the loss of sound transmission that occurs through the closing panels. Combinations of these panels, which form multilayer panels mediated by a layer of air and with or without insulating material between them, are applied. The results show that multilayered closing systems, when filled with insulating material, are an efficient solution than can provide adequate acoustical and thermal performance.

Resumo As normas de desempenho térmico de edificações têm como um de seus objetivos avaliar a envoltória da edificação, identificando aquelas edificações que são adequadas e que irão garantir um desempenho mínimo no qual seus usuários possam sentir-se em conforto. Atualmente, estão em vigor no Brasil duas normas que abordam o desempenho das edificações: a NBR 15220 (2005) e a NBR 15575 (2013). Alguns estudos apontam inconsistências nessas normas, principalmente no que se refere aos valores-limite estabelecidos para as características termofísicas das paredes e coberturas. O objetivo deste trabalho é avaliar o conforto térmico de uma edificação residencial multifamiliar adotando os valores-limite de Mahoney, comparando os resultados com os obtidos a partir dos valores normativos para cada uma das zonas bioclimáticas. A análise foi realizada por meio de simulações no EnergyPlus© para o período de 1 ano em 24 cidades brasileiras. Os resultados indicaram a necessidade de revisão, principalmente dos valores adotados para a capacidade térmica das paredes e para a transmitância térmica e a absortância solar das coberturas da norma NBR 15220. Além disso, há a necessidade de rever valores da capacidade térmica das paredes e da capacidade térmica e da absortância solar das coberturas no caso da norma NBR 15575.

Abstract One of the purposes of thermal performance standards for buildings is to evaluate the building envelope, identifying those building that are appropriate and can guarantee a minimum performance and hence the thermal comfort of users. In Brazil, there are currently two standards that regulate the thermal performance of residential buildings: NBR 15220 (2005) and NBR 15575 (2013). Some studies point out inconsistencies in these standards, especially with regard to the limit values for the thermo-physical characteristics of walls and roofs. The aim of this paper is to evaluate the thermal comfort of a multifamily residential building, adopting Mahoney's limit values, comparing these results with those obtained through the normative values for each of Brazil's bioclimatic zones. The analysis was performed through simulations using EnergyPlus© during one year in 24 Brazilian cities. The results point to the need to review especially the values adopted for the thermal capacity of walls and the thermal transmittance and solar absorptance of envelopes in NBR 15220 (2005), as well as the need to establish values for the thermal capacity of walls and the thermal capacity and solar absorptance of envelopes in the case of NBR 15575.

Abstract The comfort conditions of a given environment can directly influence the performance of the activities performed therein. When considering the school space in relationship with the user, the environment is even more important, since it may reflect fully on the learning process. This article evaluates the thermal comfort perceptions of classroom users of the Federal University of Ouro Preto, specifically the School of Mining, the Institute of Physical and Biological Sciences and the Building Block of Classrooms. The research is conducted through questionnaires and measurements of environmental variables in loco simultaneously in the three areas throughout the months of June, July and September 2011. The results were statistically analyzed using the calculation of the standard deviation from the mean operative temperature and humidity to give comfort zone. Approximately 75% of the users were satisfied with the thermal environment.

Abstract Industrialized closing systems appear as rational solutions in steel-structured construction. These closing systems, consisting of multi-layered panels, have been applied in projects where it is intended to obtain a high sound transmission loss without raising the cost and without using a lot of mass. However, acoustic isolation depends on several factors, including the type of connection between the panels, requiring a preliminary study of the acoustic performance of the closing system to prevent future interventions. This paper uses a simplified graphical method to evaluate the influence of the type of connection (line-line, line-punctual or punctual-punctual) of industrialized closing panels on the estimation of the sound transmission loss that occurs across the wall constituted by these panels. The panels are combined, forming multi-layered closings interleaved by a layer of air, either without or with a sound-absorbing material between them. The results show that it is necessary to check the effectiveness of each type of fastening of the closing systems because, for example, for the frequency range between 500 and 2,000 Hz, the sound transmission loss of a closing system consisting of cementitious plate with glass wool and line-punctual and punctual-punctual connections exceeds in 6.25% the sound transmission loss of the same system with line-line fastening. For a system composed of expanded polystyrene with glass wool, the sound transmission loss provided by line-line fastening exceeds in 7.0% the sound transmission loss of the same closing system with line-punctual and punctual-punctual fastenings.

Abstract The natural ventilation in a building performs a fundamental role in users' welfare and health, when used as a bioclimatic and architectural strategy, it can provide brighter projects. Increasing the indoor air speed ventilation has an important performance maintaining indoor air quality, contributing to thermal interactions between human body and environment, which can significantly reduce the building's energy cost. In this study, a numerical research of natural convection in single-sided and cross ventilation is developed using the finite volume method, taking account the internal heat sources influence. The numerical model is used to determine the effects of wind and thermal forces combined by analyzing the stream functions and temperature distribution within an office. The turbulence model is the two differential equations for the low Reynolds number. The building's internal heat sources influence is analyzed herein. The results show that the single-sided ventilation presents excellent conformity with the results obtained in literature. The influence of the internal heat source is considered and it has been observed that the best source position is near to the air exit for both single-sided ventilation and cross ventilation.

Uma circulação natural de ar adequada dentro de um ambiente construído, além de auxiliar na diminuição do gradiente térmico, contribui para a renovação do ar interno. Este, dependendo do perfil de ocupação do ambiente, pode ser prejudicial à saúde. Uma circulação natural pode se constituir em uma alternativa eficiente na redução do consumo de energia no condicionamento de edificações. Nesse trabalho, estuda-se a ventilação natural, dirigida pela ação combinada das forças do vento e térmicas num ambiente. Avalia-se a eficiência da ventilação unilateral e cruzada, utilizando-se o método numérico de elementos finitos, por meio do software ANSYS. O modelo numérico é utilizado na determinação dos efeitos das forças do vento e das forças térmicas combinadas, obtendo-se o fluxo de ar e a distribuição de temperatura dentro do ambiente. Os resultados obtidos são comparados com resultados de modelos empíricos, observando-se que a eficiência da ventilação cruzada fica em torno de 3,5 vezes maior do que a ventilação unilateral, aumentando os vórtices no fluxo de ar no interior do ambiente.

Appropriate natural air circulation within a structure reduces the thermal gradient, and contributes towards internal air renewal. This latter is important because, depending on the profile of occupation of the environment, the lack of this process can be harmful to the health. This type of circulation is an efficient alternative for the reduction of the consumption of energy in the conditioning of buildings. In this research, we studied natural ventilation, driven by the combined action of the forces of wind and thermals. The efficiency of the single sided and cross natural ventilation is evaluated, using the numerical method of the finite elements with the software ANSYS. The numeric model is used to determine the effects of the force of the winds and the combined thermal forces, resulting in the airflow and the temperature distribution. The results obtained are compared with the results of empiric models, whereby it was observed that the efficiency of the cross ventilation is around 3.5 times higher than the single sided ventilation, increasing the vortexes in the airflow inside the environment.

A educação é um dos fatores que mais influem no desenvolvimento de um país. Uma boa qualidade de ensino não só depende da capacitação dos professores, mas, também, das condições físicas das salas de aulas, ambientes em que os mesmos interagem com os alunos. Nesse trabalho, avalia-se o ambiente térmico das salas de aula da Universidade Federal de Ouro Preto, especificamente na Escola de Minas e no Instituto de Ciências Exatas e Biológicas (edifícios com sistemas construtivos diferentes), investigando-se a percepção dos usuários por meio da aplicação de questionários e medição das variáveis ambientais in loco, simultaneamente. Os resultados obtidos são tratados estatisticamente obtendo-se os limites de conforto para a população em estudo, por meio da análise probit, obtendo-se uma percentagem de aproximadamente 70% de satisfeitos com o ambiente térmico.

Education is one of the factors that most influence the development of a country. Good quality education does not only depend on the training of teachers, but also the physical conditions of the classroomwhere they interact with students. In this study, the thermal environment of the classrooms of the Federal University of Ouro Preto (UFOP) was evaluated, specifically at the "Escola de Minas" and the "Instituto de Ciências Exatas e Biológicas" (both with different building systems). For the evaluation, questionnaires to obtain student perceptions and measurement of the environmental variables in locowere implemented. The results were statistically treated, obtaining the comfort limits for the sample of this study by probit analysis. With this method, the percentage of satisfaction with the thermal environment was 70%.

N tecnologia light steel framing, por ser importada dos Estados Unidos, requer algumas adaptações nos projetos para adequar seu desempenho térmico no Brasil. Neste trabalho avalia-se o desempenho térmico de uma edificação unifamiliar projetada em light steel framing, considerando-se algumas estratégias de ventilação natural e a influência da inércia térmica do solo em Belo Horizonte, MG. Na determinação do comportamento térmico do modelo utiliza-se o programa computacional EnergyPlus, seguindo as seguintes etapas: caracterização da edificação, das condições típicas de exposição ao clima, do perfil de ocupação, das exigências humanas, configuração do sistema de fechamento e avaliação das condições de conforto térmico nos ambientes em concordância com as normas específicas. Observou-se que a estratégia de ventilação natural, quando adequadamente utilizada, em função das condições climáticas locais, proporciona uma melhora significativa no desempenho térmico da edificação. Da mesma forma, em função da topografia do terreno e da característica do projeto, observou-se que a influência da inércia térmica do solo somente se torna positiva quando associada às estratégias de ventilação natural e de sombreamento.

The light steel framing technology requires some design adaptations in order to have an adequte thermal performance in Brazil, since it was imported from the USA, In this study, the thermal performance of a light steel frame single-family house, in Belo Horizonte, state of Minas Gerais, was evaluated considering some natural ventilation strategies and the influence of soil inertia. To determine the model's thermal behaviour, the EnergyPlus simulation program was used. The following stages were carried out: characterization of the structure, its typical exposure to the weather; occupants' profile and their demands; configuration of closing system; and the evaluation of the building's thermal comfort conditions and to what extent they meet existing standards. The conclusion was made that a suitably ventilation system could significantly improve the building's thermal performance, if the local climatic conditions are duly taken into account. Likewise, depending on the land plot topography and the design characteristics, the influence of the soil thermal inertia, when associated to suitable ventilation and shading strategies, could be helpful to improve the design thermal performance.

Nesse trabalho, faz-se uma avaliação das intervenções, em sistemas estruturais, destinadas à restauração do teatro municipal de Ouro Preto-MG. O atual processo de intervenção se baseia em observações de outras intervenções, já realizadas ao longo da história, nas diretrizes estabelecidas pelo Comitê Internacional para Análise e Restauração de Imóveis do Patrimônio Arquitetônico (ICOMOS) e em análises laboratoriais. A recuperação de edificações de importância histórica deve ser precedida de um planejamento detalhado para que o processo de intervenção não venha a comprometer a construção original.

This work presents the results of an assessment of interventions performed in structural systems for the restoration of Ouro Preto's City Theater building. The current process of intervention is based on observations of other interventions performed along the previous years, on guidelines established by the International Council on Monuments and Sites (ICOMOS), and on laboratory tests. The restoration of buildings of historical importance must be preceded by a detailed planning in order to avoid having an intervention process that compromises the original structure.