[pt] Nesta dissertação estuda-se o sistema construtivo em alvenaria estrutural na cidade do Rio de Janeiro face aos conceitos de construção sustentável. Avalia-se esse método construtivo em seus detalhes de execução, materiais utilizados e outros benefícios na obra como redução de resíduos e ganhos em prazo de construção. Também são analisados impactos qualitativos no produto e os aspectos sociais e culturais devido as limitações técnicas do sistema bem como as legislações que têm influência. Levando-se em consideração as necessidades atuais do mercado imobiliário na busca por processos sustentáveis, foram
analisadas as principais certificações. Tem-se como principal conclusão que nem sempre o processo atenderá de forma completa as necessidades de determinado empreendimento em função de algumas limitações técnicas. Do ponto de vista da sustentabilidade, o processo apresenta qualidades devido à modulação do sistema que gera menos desperdícios, porém, pode limitar a concepção de um produto
diversificado e mais confortável através de soluções diferenciadas de planta e fachada, por exemplo. Mesmo que as construtoras tenham tentado utilizar o sistema em padrões médios de empreendimento, com preços de venda que giram em torno de 7.000 a 8.000 reais por metro quadrado, a solução não teve boa aceitação tanto pelos construtores como pelos clientes, e nota-se que o mesmo é utilizado em larga escala para empreendimentos de padrões populares. / [en] In this thesis the use of structural masonry constructive system is investigated in light of the concepts of sustainable construction in the city of Rio de Janeiro. This study is based on the evolution and growing importance of the construction sector within Brazilian economy, and the current trend in the construction market in the search for processes that minimize impacts on the environment with rational use of natural resources. The earliest records of civil construction activity in the city of Rio de Janeiro date from the colonial period, at a time which those activities were unregulated. In 1810 King João VI established the engineering school. The period between the late nineteenth century and early twentieth century was a time of intense economic transformation with the decay of the coffee plantations and the beginning of the industrial development. In 1940 there was a breakthrough in civil construction in Brazil, when the
sector was considered one of the most advanced of its time. In 1971 there was great progress in the sector of construction in Rio de Janeiro with the creation of BNH, Banco Nacional da Habitação, and the Law of the Real Estate Development (Lei das Incorporações). The 90s were marked by the improvement of the qualification of the workforce, resulting in better products. The 2000s were distinguished by the boom in housing construction in the west zone and the expansion of large construction companies landbanks. In 2008 the growth was toward the north zone, however, by the end of that year, with the peak of the global crisis known as Subprime, the sector started suffering from a poor performance cycle until in
the first half of 2009. The government program called Minha Casa Minha Vida was launched providing a better environment, with the incentive to produce one million new housing units. By the second half of 2009 the construction market was fully recovered. Many companies created new brands or subsidiaries to focus their business in this new market niche, and the use of large-scale structural masonry was
considered the most suitable technology to be used in this type of construction. In 2011, the sector continued to grow driven by the demand fostered by the Olympic Games and the approval of new urban zoning laws. In this study the major projects launched in the city of Rio de Janeiro between 2005 and 2012 were mapped as well as the number of constructions that adopted structural masonry during this period.
Impacts of civil construction on the environment range from the generation of raw material to the end of the useful life of products built. As a consequence of the growth experienced by the civil construction sector and its great economic impact, principles of sustainability standards and certifications arouse aiming the
achievement of sustainable development in the entire production chain. Over the years, several international events debated on sustainability. In 1713 Carl Von Carlowitz published the first treaty on sustainable use of forest resources. In 1976 the first world conference on housing and environment was
held in Canada. The system in structural masonry is ancient and its use dates back to early human activity process. Around 4000 years before Christ structures were employed for varied purposes and materials were usually blocks of clay and stone. In the seventeenth century the system becomes a construction technology based on principles of static. Element resistance tests begun to be performed in the nineteenth and twentieth centuries. The projects were based on limited empirical calculation methods, resulting in very thick walls and slow production speed. In the 50 s there was a revival of interest in structural masonry driven by the shortage of building materials in Europe, such as steel. The use of structural masonry in Brazil began in the sixteenth century, during the colonial period; yet, the process was not rationalized. By the 70s, the structural masonry was considered engineering technology in Brazil and projects started to
be based on scientifically validated principles. With this evolution, it became more efficient and an economical alternative, although still somewhat precarious. Structural masonry achieved its consolidation with official norms in the 80s. Ancient definitions considered that the buildings should be formed of natural
or artificial stones linked together in a stable manner by the combination of joints and mortar (or only by one of the two), capable of resisting only to compressive stresses. Currently, buildings in structural masonry are formed by industrial blocks (ceramic or concrete) designed and sized by calculation procedures to support loads beyond their own weight and resist compression. They are linked together by the interposition of mortar and can contain rebar in concrete or mortar in horizontal and / or vertical plane. They are classified as armed, unarmed, partially armed or pre-stressed. The structural masonry consists of four main components. The units are the basic components that define the resistance characteristics. Units can be concrete, ceramic or sand-lime blocks, solid or hollow. The mortar is a mixture of sand, cement, lime and water responsible for laying and unifying the units. It transmits and uniforms the stresses throughout the blocks, seal out water and wind and even out small deformations. Rebars are steel bars surrounded by grout that make all components of the masonry work together. The grout is a very fluid micro concrete with aggregates and it is responsible for the union of blocks with rebars within its hollows.
The rationalization of structural masonry brings results by improving productivity and quality, with consequent increased value added. It also incentives increase in productivity and cost reduction in the supply chain, while meeting construction standards. As a result, the final consumer can buy at a lower price. Modulation was already used by the Greeks, Romans and Japanese. It represented to them, respectively, aesthetic, functional and aesthetic and functional character. At present time, for the modulation process to be harmonized, it is needed to update the standard as to the sizing of the blocks. The incompatibility between the dimensions of the components of the building often results in large thicknesses dimensional settings and designs solutions that do not properly address these adjustments, which end up being performed impromptu in the work site. The advantages of modulation are: simplification in project design, standardization of building components, optimization of the dimensions with reduction of different shapes, less interface problems between components and subsystems, standardization of detail and dimensional accuracy, rationalization and simplification in the execution of the work due to ease of assembly, reduction of material breaks, thus avoiding losses in construction. The disadvantages are: the need to have standardized components without dimensional and qualitative variation in the market, and need for investment in preparation and training of manpower. The definition of the system to be used by the constructor occurs in the study phase. It is usually observed: the type and purpose of the project, the maximum number of floors, the ceiling heights between slabs, the size of compartments and wall allocation, the eventual need for sheltered parking and its mixed solution
analysis, the size of balconies, the need for flexibility of plans, if penthouses should have swimming pool, the dimensioning of the common areas. In the cases where the product can fit in structural masonry guidelines, this has been the preferred construction system. The project in structural masonry should consider the coordination between the various project disciplines with the integration between the design teams. Schedule of the project design should be prepared with the correct interaction of reconciliations. The design should be standardized and simplify the solutions and should provide full details of projects to avoid doubts and execution errors during construction. Wall rebar can be done directly with interlocking blocks, requiring interposition between blocks of 50 per cent in intercepted wall. It also can be done by
placing the rebar in mortar joints with 90 angle, as well as through folded steel bars, industrialized trusses or staples, steel decks or similar materials of proven resistance. Electrical installation must be standardized in the predefined rows heights. The hydraulic and gas installations must be apparent and not embedded in order not to interfere in modulations. The project modulated masonry must have solutions that minimize the need for adjustments or additional elements while helping reconcile the different project disciplines.
This constructive method is examined regarding its execution details, increase in production and other benefits to the construction itself. Furthermore, qualitative impacts on the product and the social and cultural aspects due to the system s technical limitations and the applicable laws and regulations are analyzed. The main certifications like AQUA, LEED, PROCEL EDIFICA, CASA AZUL, SANTANDER OBRA SUSTENTÁVEL and QUALIVERDE were analyzed in view of the current necessity of the real estate market to seek for more sustainable construction processes. It was analyzed the positive and negative aspects, as well as possible limitations of structural masonry for obtaining the building approvals. Two recently launched projects in structural masonry were analyzed. Through case studies one can compare them to competing projects built in conventional reinforced concrete structure and it is possible to understand the main differences between the products. The projects were also evaluated for the possibility of obtaining green building certification. AQUA was chosen as the reference certification. It provided the features used in the comparative between the different systems. To meet all categories of the certification, some aspects of the project might need to be adjusted, such as layout, wall thickness and span dimension.
The main conclusion is that structural masonry will not always completely fulfill the needs of various projects because of certain technical limitations. Taking sustainability into account, structural masonry has a number of benefits beginning with the modulation of the process which generates less waste. However, it can limit the design of more comfortable and sophisticated products, for example with differentiated solutions for layout and façades. Even considering that some companies have used structural masonry in the construction of buildings for the middle class, with selling prices around BRL 7,000 to BRL 8,000 per square meter, this solution was not well accepted either by the contractors or those clients, whereas it is largely used in lower class constructions.
| Identifer | oai:union.ndltd.org:puc-rio.br/oai:MAXWELL.puc-rio.br:55563 |
| Date | 29 October 2021 |
| Contributors | CELSO ROMANEL |
| Publisher | MAXWELL |
| Source Sets | PUC Rio |
| Language | Portuguese |
| Detected Language | English |
| Type | TEXTO |
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