Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761
Construction of Concrete Walls: Potential in the Industrialization of
Armed Structures for Building Fences
Construção de Paredes em Concreto: Potencialidade na Industrialização
de Estruturas Armadas para Vedação de Edificações
DOI:10.34117/bjdv6n5-302
Recebimento dos originais:20/04/2020 Aceitação para publicação:15/05/2020
Leila Soares Viegas Barreto Chagas
PhD Civil Engineering from Federal University of Pernambuco – UFPE Federal Institute of Sertão Pernambucano – IF Sertão
Address: BR 232, Km 504, sentido Recife, Zona Rural Salgueiro – PE E-mail: leila_viegas@hotmail.com
João Victor da Cunha Oliveira
MSc Student Post-Graduation Program in Materials Science and Engineering from Federal University of Campina Grande – UFCG
Federal University of Campina Grande – UFCG
Address: R. Aprígio Veloso, 882 - Universitário, Campina Grande – PB E-mail: joaovictorwo@gmail.com
Arnaldo Manoel Pereira Carneiro
PhD Civil Engineering from University of São Paulo – USP Federal University of Pernambuco – UFPE
Address: Av. Prof. Moraes Rego, 1235 - Cidade Universitária, Recife – PE E-mail: arnaldo2164@hotmail.com
ABSTRACT
For many years there has been an accommodation by the construction industry because it is believed to be a craft, rustic activity, being considered cautious and even inappropriate for the insertion of new building systems. Nowadays, the reduction of costs and lead times, as well as the increase of profit margins, are the main goals of construction companies owners, where in the construction industry, in the vast majority of projects, the speed of construction and the use of new technologies are market demands, which makes it more competitive. The challenging globalized scenario encourages the standardization of future development guidelines for all industries in the country, particularly construction. This paper presents the industrialized construction as well as the constructive characteristics of this system and the expectations of its wide use in the construction industry through a study of case in a work placed in Santa Rita, Paraíba. The project is part of the Minha Casa Minha Vida Program of the Federal Government.
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761
RESUMO
Há muitos anos que a indústria da construção é acomodada porque se acredita ser uma atividade artesanal, rústica, sendo considerada cautelosa e até inadequada para a inserção de novos sistemas de construção. Atualmente, a redução de custos e prazos, bem como o aumento das margens de lucro, são os principais objetivos dos proprietários de empresas de construção, onde na indústria da construção civil, na grande maioria dos projetos, na velocidade de construção e no uso de novas tecnologias são demandas do mercado, o que a torna mais competitiva. O cenário globalizado e desafiador incentiva a padronização de diretrizes de desenvolvimento futuro para todos os setores do país, particularmente a construção. Este artigo apresenta a construção industrializada, bem como as características construtivas desse sistema e as expectativas de seu amplo uso na indústria da construção através de um estudo de caso em um trabalho localizado em Santa Rita, Paraíba. O projeto faz parte do Programa Minha Casa Minha Vida do Governo Federal.
Palavras-chave: Construção, Construção de Muros de Concreto, Industrialização de
Estruturas Armadas
1. INTRODUCTION
According to El Debs (2000), civil construction presents characteristics of a backward industry, when compared to other industrial sectors, because it presents, in general, low productivity, big waste of materials, slowness and low quality control. Such references are justified by many resistances that appear for the insertion of new technologies, but gradually they have been overcome.
According to Sabbatini (1989), evolving towards improvement as an industry is a natural path for the construction industry, as the challenging globalized scenario encourages the standardization of future development guidelines for all industries in the country, especially for construction.
The changes suffered by the construction industry in the last decade were so considerable that it can already be considered one of the main and most important economic sectors of the country, as it represented around 8.6% of the Brazilian GDP (Gross Domestic Product) in 2016 (FIESP, 2017).
Since civil engineering is an industry that encompasses the conception, design, construction and maintenance of all types of infrastructure necessary for the well-being and development of society, in addition to preserving the natural environment, it is of great importance that it expands its constructive system.
Thus, this area is dedicated to the creation of buildings, bridges, tunnels, power plants, industry and many other types of structure, such as the one that will be covered in this paper:
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 Industrialized construction. The system consists of molding massive reinforced concrete walls and slabs with centralized wire mesh. The structure is sized for each specific building architecture project. The production process of the construction system allows the geometric control of the parts and the obtaining of surfaces suitable for finishing. The thickness of the walls and slabs is 10 cm. Concrete wall constructions were widely used in the 70's and 80's, however this method has not yet been consolidated in Brazil, since its use in small works is unfeasible because of low cost-benefit. By this time industrialized constructions using cellular and conventional concrete had already been tried. Currently, the Brazilian construction industry is benefiting from the high demand for buildings, especially following popular housing, with very large housing units. This scenario requires construction companies to focus on durable, short-term construction work with structural safety and within established technical standards. To overcome these obstacles, the answer was concrete wall construction. Unlike conventional construction where all the tasks of the works are performed through the human element, industrialized construction uses automated equipment to manufacture and assemble its components or building elements.
2. THEORETICAL FRAMEWORK
2.1 INDUSTRIALIZED CONSTRUCTION
Industrialization of civil construction can be defined as the “use of technologies that subsist to the skill of handicrafts through the use of machines” (ROSSO, 1980).
According to Rosso (1980), there are two types of industrialization within construction. The first, called Closed Industrialization, is less flexible, where the industry makes the final product available on the market, that is, an entire module of a building. Thus, the architect who needs to adapt his project to the module that is provided, not allowing flexibility of creation. The other type, called Open Industrialization, is more flexible, and the industry supplies the market with prefabricated components that can be combined in many ways to make a building. This second type of industrialization, which is the focus of the present work, guarantees the architect great freedom of creation, defining only the constructive method to be used.
According to Lima, Marcandier and Moreira (2007) the practicing of construction in Brazilian cities is still entirely centered on the construction process that can be called conventional: reinforced concrete structures cast in place with ceramic brick fences, to which the other elements (such as frames, finishes, pipes and equipment) are added later and by
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 partial scrapping of what was done. The main disadvantages of this process are the high consumption of non-renewable natural resources, the heavy manual labor of the construction site and the large amount of solid waste generated by the waste. The concrete wall construction system using formwork for its molding is a method that uses prefabricated formwork, where all the walls are molded in a single concreting step with the electrical and hydraulic installations, fasteners, gearboxes, doors and windows inserted in the structure. Another great feature of the system is the focus. This system is recommended for big projects that do the same service over and over again, such as the work that will be presented in this paper.
2.2 SOCIAL HOUSING
Every project comes from a need, whether it is personal, for business or by the government. In the case of housing of social interest, article 6 of the Federal Constitution of 88 highlights housing as a fundamental human right in order to demonstrate that this right is immediate and fundamental. Among so many materials used, men made use of material that his purchasing power could acquire, so between rich and poor, mansions and slums began to emerge.
Junqueira and Vita (2002) note that nowadays housing acquisition is part of the set of main aspirations of a significant portion of the Brazilian population, although it has been losing relative importance for education, health and private pension. This relative loss of importance was not due to the desire of housing by the population, but largely due to the growing deficiency of these public services.
For Fernandes (2003), housing performs three different functions: social, environmental and economic. As a social function, it has to shelter the family and is one of the factors of its development. According to Abiko (1995), housing becomes the space occupied before and after work, accommodating the primary tasks of food, rest, physiological activities and social life. Thus, it is understood that housing must provide the basic principles of habitability, safety and health of the population.
The redirection of urban and housing development policies from the second half of the 1970 onwards pointed to a new pattern of public intervention that prioritized the urbanization and land tenure regularization of the favelas. From this concept arise the housing of social interest. The Federal Installment Law (Law No. 6,766), in 1979, was another important element for this process of redirecting housing policy, enabling specific rules for land parceling in areas of social interest.
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 The production of housing units from the architectural and urbanistic point of view is still a subject of great controversy, since the public authorities prioritize the economic issue and the practical part of the process, which always leads to repetitions of residential units' projects, which generates the oblivion of aesthetics, that is, the architectural beauty that everyone should have access to. The large-scale production methods of the vast majority of social housing that must be designed to meet immense demand are seen as the major point of absence from architectural concern.
Making the care of low-income workers financially viable, ensuring dignity and architectural quality is not a priority of government policies. Few architects are looking for a way of replacing the repetitive and mass production in architectural projects with a personalized housing and urban production characterized for social interest.
Housing geared towards social housing also has deficiencies in access to infrastructure or excessive densification, they are families that do not need, just a new home, but interventions for decent housing conditions, which require action articulated with urban policies, land and sanitation, which can only be implemented by the government, and urbanized land, provided with services, equipment and infrastructure. The final quality of the residential unit is directly influenced by the materials and components used during the stages of the construction process, facilitating even the emergence of pathologies such as cracks.
2.3 PUBLIC WORKS
Contracting public works is a formal procedure, triggered in successive steps to seek the selection of the most advantageous proposal for the Administration. In this process, the public manager will be bound by the Constitutional Principles that guide his performance, listed expressly in the caput of art. 37 of our Magna Carta: Legality, Impersonality, Morality, Advertising and Efficiency (BRASIL, 1988).
Law 8.666 / 1993 governs the bidding and administrative contracts, which establishes the procedures, modalities, rules, principles, responsibilities, administrative and criminal sanctions as well as possible remedies. The bidding modalities are also provided for in the referred law, updated by Law 9.648 / 1998, and the trading mode was established by Law 10.520 / 2002. Thus, before purchasing a product or hiring a service or even manifesting itself for possible purchase, the public manager must follow the rules according to the Federal Law N. 8.666/93, called bidding, which includes engineering services for public works.
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 In the case of private works, the construction industry, due to competition, has increasingly invested in quality to meet the changes, changes that are imposed by the market and that every day has been demanding improvements on the materials used, improvements in customer relationships and shrinking profit margins, and improvements that aim for greater efficiency of production processes through changes in all stages of their production process.
In order to raise the quality standards of the construction sector, not only private but also public, it is necessary that all involved are committed to the quality of their processes and products and the quality of the final product, with the final purpose of the user satisfaction.
The public sector must also follow this evolution as well as the private sector, since public works represent a huge portion of national fixed investments. It is therefore one of the most important engines of the national economy, mainly due to its great contribution to job creation.
However, lack of rationalization, deficient construction processes, equipment shortages, unsatisfactory training of technical staff and specialized personnel, and lack of standardization and certification of conformity of materials and building elements have led the public Works sector and civil construction to low productivity and quality deficiency.
Whenever there is a report on public works, it is impossible not to mention the waste of resources that exists in Brazil, which is in fact notorious and is materialized by the number of unfinished works, the poor quality that are built parallel to the exorbitant costs, as well as the large amount of materials that are wasted to build them, which is a problem found in most municipalities of the country.
For a public housing project to have quality it is necessary to have a good project. Every good project, no matter how simple it is, must be carried out through good management focused on the planning, integration, elaboration, analysis and implementation, in an interdependent, interacting and interrelated way. These management activities are performed in an integrated manner, simultaneously, with the same degree of importance and complementary to each other (CAVALCANTE, 2000).
Therefore, it is evident that the performance of the control bodies (Audit Courts, external control bodies) contributes significantly to the minimization of irregularities in public works. The more effective performance of the Internal Control agencies, in the execution phase of public works, would certainly greatly contribute to the improvement of the inspection procedures of the works, making them more efficient and with a higher quality, whether built
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 using conventional construction systems or using systems. Innovative constructions, such as social housing constructions using concrete walls.
2.4 MODEL AND CHARACTERISTICS OF THE CONSTRUCTION METHOD
According to Vieira (2010), in the past the construction process was chosen, basically, by analyzing two elements, as follows: the company's culture and the cost generated. However, today this decision is made focusing on the above mentioned items, the structure typology, the final product quality and, mainly, the productivity of the construction process.
The method is inspired by the successful and successful experiences of industrialized constructions in cellular concrete (Gethal system) and conventional concrete (Outinord system), which were known worldwide in the 70's and 80's. However, due to the lack of scale and continuity of works in these standards, especially with the financial limitations of the time, these technologies were not consolidated in the national market. With the growth of the Brazilian real estate market and the continuous public measures to expand the housing supply, the concrete wall system represents a feasible solution for large scale production (Téchne Magazine, 2009).
The construction method called Concrete Wall is characterized by the replacement of the traditional columns and beams by the concrete walls, which perform structural and structural functions the focus. The structural elements are molded in a way using completely modulated shapes that allow the molding and concreting of all walls and slabs of a construction cycle in one step.
The standard for in-situ cast concrete walls, published by the Brazilian Association of Technical Standards (ABNT), came into force on May 10, 2012, one month after its publication. NBR 16.055/2012 ("On-Site Molded Concrete Wall for Building Construction - Requirements and Procedures") standardizes the sizing and execution of the system, which has not been standardized yet, despite being used for about 30 years in Brazil. (Téchne Magazine, 2009). “This technology, which underpinned the so-called industrialized construction, offers perfect technical and economic conditions for large-scale housing production without compromising on quality and comfort” (ABCP, 2008).
The frame adopted in practice in the concrete wall system is the welded mesh positioned on the vertical axis of the wall. Edges, doorways and windows receive reinforcements from screens or bars of conventional reinforcement. In higher buildings, the walls should receive two layers of welded mesh, vertically positioned, and vertical reinforcements at the ends of
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 the walls. Reinforcement must meet three basic requirements: resist stress on the walls, control the shrinkage of concrete and structure and fix the electrical, hydraulic and gas pipes (ABCP, 2007).
Regarding the formwork, its system is composed of temporary structures, whose purpose is to shape the fresh concrete. It comprises panels of formwork, shoring, crimping, uprights and scaffolding, including their supports, as well as the joints between the various elements. The formwork system shall be designed and constructed to have: resistance to actions to which it may be subjected during the construction process; sufficient rigidity to ensure that the specified tolerances for the concrete wall structure and design specifications are met and the integrity of the structural elements is not affected and the tightness and compliance with the geometry of the parts being cast (NBR 16055 - 18.2.1).
The material used in the formwork system shall meet the requirements of 18.2.1 and the product standards. (NBR 16055 - 18.2.2). The formwork system can be made of wood, steel, plastic or a composition of materials, such as sheet steel made of structured light steel profile. However, in Brazil, in building construction works it is possible to observe the predominance of the use of formwork made of aluminum plates and structured profiles in concrete wall constructions, and before concreting, the electrical and hydraulic installations are already embedded in the walls, door and window frames, roof fasteners and other project specific ones. This construction system is based on industrialization concepts, with standardized and repetitive processes, material mechanization, and labor qualification. The control exercised throughout the construction process will be differential to the results of technological quality obtained, in addition to directly influencing productivity and cost. In addition to material savings, as there is no splatter, plaster, and plaster lining only where deemed necessary due to the facilities. The final coating finish is applied directly to the concrete wall and slab bottom. The low generation of waste on the site is also due to the fact that the work does not require cuts and so many other manipulations that generate debris. Being a construction method considered new in the country, there is still no quantitative data about its waste produced, but visually in the construction site it is clear that they are minimal and almost nonexistent.
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3. METHODOLOGY
This work is of a practical nature supported by specialized literature on the subject, as it is a survey of the main information about the construction system using concrete walls, and the qualitative analysis was chosen for investigating a reality that cannot be quantified.
At first it was made a historical survey of the work, through projects and descriptive memorial, and research of ABNT norms. Based on these data, all the stages of the present paper were explained aiming at the necessary clarifications on the theme, because “it employs research strategies that involve simultaneous or sequential data collection to better understand the research problems” (CRESWELL, 2007).
For the accomplishment of the study it was used as object the work located in the municipality of Santa Rita, Paraíba. The project is part of the Minha Casa Minha Vida Program - PMCMV, of the Federal Government, and is aimed at popular housing with income of up to three minimum wages. The work includes 576 housing units, divided into 18 blocks of 4 floors, ground floor plus three. Each block has 32 apartments, 8 per floor, divided into 32 units with 44.00 m², and one unit adapted for people with special needs-PNE.
The choice of the work as a sample for this work was due to its construction method which is not a conventional method, as it uses prefabricated formwork, where all the walls are molded in a single concreting step already with the electrical installations and fittings, fasteners, door boxes and windows embedded in the structure.
This work also had the help of the use of references about the subject, as a way to guarantee the veracity of the observations and conclusions exposed, and on-site visits were made to perform photographic records, proving that one of the advantages regarding the use of the system is a leaner job, with less material and production waste.
4. RESULTS
4.1 DESCRIPTION OF THE WORK
The tight schedule and rationalization of the construction site were reasons why the company chose to carry out the work using concrete walls. During the visits, the technicians stated that among the variables to choose the building system of concrete walls, influenced the: - Speed of execution; - Decrease of staff and decrease of water consumption in the work; - Reduction of later pathological manifestations due to the emergence of moisture, because the incorporation of air creates a barrier that prevents moisture condensation inside the walls, which could cause mold even in the furniture; - Possibility of changes, as the formwork
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 material and its closure, as well as the type of concrete used, are some items that can change according to the planning of work and also the reduction of the amount of debris.
The building entrepreneurs also informed that what motivated them mostly because of the decision to use the building system were the building characteristics of the work to be performed: the need for large-scale construction by the size and quantity of residential units, the need to build with speed for rapid financial return and the need for project standardization. The work, according to its physical schedules that are used, has a deadline of 18 months, and it is expected to be delivered in June 2017. With initial workforce of 50 employees, the work currently employs 102 people, including the administrative sector.
With an initial workforce of 50 employees, the work currently employs 102 people, including the administrative sector.
The construction capacity is 01 floor every 5 days per team, where the assembly takes from 3 to 4 days and the concreting 1 day and the dismantling 1 day. The team is made of 22 employees, including masons, housekeepers, shipowner, electrician, plumber and foreman.
The project that consists of building popular houses with concrete walls using the industrialized construction method is from the Paraíba State government, managed by CEHAP - State Company of Popular Housing and financed by Banco do Brasil buyers (Figure 1).
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 Due to the smaller wall thickness when compared to the conventional masonry system, the concrete wall system allows us to gain useful floor area for the same total area of the unit. Therefore, there is no justification for not building in a way that is adaptable to all needs, so there is one residential unit per building that is adapted for PNE - People with special needs (Figure 2).
Figure 2 - Residential unit for people with special needs: Wheelchair
4.2 ASPECTS RELATED TO SUSTAINABILITY
The execution of residential units in the housing development, opting for industrialized buildings, using concrete walls, plays a fundamental role especially in social gains in developing countries such as Brazil, as it directly interferes with the minimization of losses, efficiency and durability of products (Figure 3).
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 Figure 3 - Construction efficiency during all stages of the construction process
When in a work there is the option for industrialization there is already a reduced use of materials and, as a result of energy consumption, the work becomes a less aggressive construction to nature, the parts that make up its systems do not require the use of boards, boards and slats. In wood, the concrete is executed in such a way that traces and material consumption (water, sand, gravel, additive and cement) can be controlled and, however, there is a substantial reduction of waste at the construction site (Figure 4).
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 4.3 ECONOMIC ASPECTS THAT ENABLE THE USE OF CONCRETE WALLS
Regarding to the economic aspects, construction systems that use concrete walls have a cost below the conventional system when considering the cost benefit. Another point that generates savings is the reduction of wasted materials, considerably reducing the production of waste in the works, which occurred in the housing development (Figure 5).
Figure 5 - Reduction of waste materials at the construction site
The total construction time is another major attraction in relation to the economic aspects that make the use of concrete walls possible. The possibility of performing simultaneous tasks such as site preparation and concrete fabrication for the walls, in addition to the efficiency presented in the construction, brings much faster results for the completion of the work (Figure 6).
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 With respect to traditional constructions, the time is halved or even less when using concrete walls in construction, especially when good planning is done.
The choice of concrete wall chosen for the construction of residential units of Conjunto Rosa Luxemburg for social interest has greater economic potential and durability than conventional constructions because of the highly enhanced and optimized use of materials.
4.4 TECHNICAL ASPECTS THAT ENABLE THE USE OF CONCRETE WALLS
Regarding to the technical aspects that enable the use of concrete walls in the housing project used as a study object, a major emphasis on such topic is the increase of constructive rationalization generating speed of execution, strict process and materials quality control. (Figure 7) and modular coordination.
Figure 7 - Rigid control of the concrete used
The choice of using concrete walls in the housing development provided a lot of convenience (Figure 8), because it is a quality material, it is incredibly receptive to the needs of the designer, thus being economically achievable, as it does not need in projects of complex configurations.
Another important technical aspect to be observed in works built with concrete walls is the high fire resistance, which achieves better performance compared to conventional masonry that is built with ceramic blocks. In terms of planning, control and agility there is no doubt about the adoption of the industrialized building system using concrete walls, as it presents a much more satisfactory result than other methods.
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 Figure 8 - Constructive practicality in works with concrete walls
In masonry, because there is proven low cost in labor, even with the high values spent on the formwork (1 million reais, can reuse 200 times), because the workforce is much smaller, generating less labor charges for the company executor and generating low maintenance after the delivery of the work, as currently there are 102 people involved in the construction process, including the administrative sector. For the execution of 1 floor every 5 days per team, the assembly takes from 3 to 4 days, the concreting 1 day and the dismantling 1 day, requiring 22 employees, including: bricklayer, servant, shipowner, electrician, plumber and in charge (Figure 9). Technical managers, because of their experience in construction work, say that it is possible to reduce up to 50% of the time it would take in a conventional construction site, which saves on construction site costs and the owner of the performing company gets a better financial return fast.
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 The final finish is also considered as an advantage, because as a result of a monitored process and little subject to improvisation, the work itself gains in quality. Concrete walls do not require mortar coating, only painting or texture directly on the finished concrete, which is an advantage when compared to conventional masonry works. Another advantage is that all electrical and plumbing installations can be embedded in the walls and not apparent. Concerning labor, it needs to be a little more qualified than the labor used for conventional construction, because prior training is required on the execution of concrete walls, this generates more peace of mind about the quality of the final product (Figure 10).
Figure 10 - Manpower used for wall and concrete construction
Regarding to the coverage of possible visual flaws in the walls, they can be corrected by using the very texture that is used for coating, which becomes an advantage, as the possible flaws are not apparent.
4.5 DISADVANTAGES
The constructive model of cast-in-place concrete walls requires the application of formwork that assists in the containment of concrete, hardware, hydraulic and electrical piping, junction boxes, power board, being considered a disadvantage. Other constructive aspects considered disadvantages are: - High initial investment; - Designs cannot be changed; - High cost of forms.
During the execution of concreting, errors such as lack of vibration of the concrete, causing the appearance of air bubbles or excessive vibration of the concrete, inducing
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 segregation between the coarse and fine material, are mainly responsible for the appearance of cracks. Another mistake, sometimes made, is the malpractice during the execution of the building installations and wall frames, so that in the act of concreting they leave the desired position. As a result, the installations clog and the reinforcement arises on the concrete surface. The consequence of the malpractice in the execution of the steps of a concrete wall work is the generation of a rework with a high degree of difficulty. In most situations, the solution to the error involved involves: breaking the concrete, repairing it, and filling the opening again with concrete. These operations are difficult to perform as they work with concrete and not masonry finishes. The result of these “extra” operations is higher material and labor costs.
The forms used in Rosa Luxemburg ensemble, for example, were bought at the cost of R $ 1 million; The justification for this value is the reuse of them 200 times, but in practice did not meet 50% of the promised (Figure 11), so currently in the work on site are also found rented forms, at the cost of $ 80,000/month
Figure 11 - Purchased forms that had problems
The extremely high cost of the formwork acquisition turns out to be a disadvantage when choosing to build using concrete walls, as this is what generally prevents small builders from being able to apply this construction method, where in the case of construction work. Rosa Luxemburg set has also become a problem.
Another disadvantage to be presented is the issue of transporting the formwork, which, even being the responsibility of the manufacturer or lessee, must be observed in order to identify possible damage caused in the act of transport, so a logistics is required by those involved in the process. According to the technicians responsible for the work, the rented formwork met and better meet the needs of the work (Figure 12), because the defects presented
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 by the purchased were related to locking, which would impair the measurements of the walls after their removal, a fact that does not occurred with the rented forms.
Figure 12 - Leased forms that are currently used
Concerning to the workmanship, it needs to be a little more qualified than the workmanship used for the conventional construction, because it is necessary a previous training for the perfect execution of the concrete walls, because any human error interferes with the final quality of the work. Therefore, the option of using concrete walls in construction can be considered a disadvantage because it limits the type of workforce and can be considered an advantage because it increases the quality of the construction.
Another disadvantage to be analyzed is the architectural issue of concrete wall works. Not that this constructive process is limited as to the competence to build designs in different ways, but once built, there is no way to make internal changes in the organization of the walls. As in this construction process each wall is part of the building structure, it is not allowed, for example, to remove walls, open doors and windows outside the project, or to make an opening in the partition wall between the living room and the kitchen so that there is a communication between both (American style). However, this architectural limitation is not peculiar to the concrete wall construction process, but is also characteristic of its main competitor in low standard works: the construction of structural masonry.
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761
5. CONCLUSIONS
It is concluded from the work used as object of study, that the option for the building system in industrialized construction executed with concrete walls when compared to the traditional construction methods and other building materials, have innumerable positive characteristics, even though there were some disadvantages regarding to your use.
Concrete wall construction systems when compared to traditional construction systems, in view of the values presented with the formwork costs may seem to be more expensive, but in relation to the cost benefit in terms of agility and reliability it is clear that the system in Concrete walls used for the execution of residential units have some advantages over technical and economic aspects and a better satisfactory end result over other existing conventional systems, such as masonry construction; The decisive factor for the winner of the bidding project for the residential units of Conjunto Rosa Luxemburg is to choose the use of concrete wall construction.
It was also possible to conclude that the economic viability cannot be based only on the final cost spent by the executing construction company, because it must be evaluated many aspects such as time of execution of the work, optimization of the work and reliability in the employed system. Regarding the technical feasibility regarding the option to use the execution of concrete walls, through the studied work, it is noticed that the training and awareness of the work teams are sufficient elements to fit them into this quality management system, because when If work is done using conventional building systems, the difficulty of managing awareness systems for the implementation of quality management systems is much greater, as the manpower employed to work with an unusual building system needs to be much more qualified.
Regarding the option of using concrete walls for the construction of the Rosa Luxemburg Assembly, it is increasingly important to disclose the potentiality of using the chosen building system, as this choice provides several architectural opportunities and numerous other advantages, which make the construction of walls in particular an extremely competitive building system, where in Brazil its use does not yet provide so much credibility and reliability on the part of many builders and designers, due to the culture that the construction industry shows that the reliable is only the conventional one.
The use of new building systems and increasing competitiveness in this area requires the building industry to constantly update itself, improving its efficiency and working conditions
Braz. J. of Develop.,Curitiba, v. 6, n.5, p.28015-28035 may. 2020. ISSN 2525-8761 through the development and technological innovation of new building systems and processes, as has been the case the case of the work chosen as the object of study for this work.
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