ABSTRACT The technology provided by greenhouses is essential for protecting crops sensitive to bioclimatic adversities and for improving agricultural production indexes. However, the need to know the exact interaction between the flexible coating and the structure under wind action has motivated new studies. The objective was to perform an in-depth review of the scientific and technological advances regarding methodologies to obtain parameters related to wind actions that are essential for the structural safety of greenhouses. This study showed the relevance of experimental methods; however, the limitations of the study are diverse, as field experiments require the construction and modifications of a prototype, which demand time and financial resources. Experiments in wind tunnels with models on a reduced scale have contributed significantly, as it allows to control the wind flow; however, in plastic-covered greenhouses, discrepancies occur due to the impossibility to represent the aeroelasticity of the construction. Modeling via computational fluid dynamics (CFD) has proven to be a solution for extrapolating limitations in experimental methods by facilitating changes in the construction model and wind flow. In addition to pure turbulence models, studies on hybrid turbulence models (Scale-Resolving Simulation) must be deepened to obtain greater accuracy of pressure coefficients. The complexity of the subject and the need for new contributions to plastic-covered greenhouse projects are a reality, which outlines a promising horizon for research development in the rural construction sector. indexes However indepth depth however diverse prototype resources significantly flow plasticcovered plastic covered CFD (CFD ScaleResolving Scale Resolving Simulation coefficients reality sector

ABSTRACT Widely disseminated in both national and international scenarios, greenhouses are agribusiness solutions which are designed to allow for greater efficiency and control of the cultivation of plants. Bearing this in mind, the construction of greenhouses should take into consideration the incidence of wind, and other such aspects of comfort and safety, and ensure they are factored into the design of structural elements. In this study, we evaluated the effects of pressure coefficients established by the European standard EN 13031-1 (2001) and the Brazilian standard ABNT (1988), which are applicable to the structures of greenhouses with flat roofs, taking into account the following variables: roof slope, external and internal pressure coefficients and height-span ratio of the structure. Using the ANSYSTM computer program, zones of columns and roof were discretized by the Beam44 finite element to identify the maximum and minimum stress portions connected to the aerodynamic coefficients. With this analysis, we found that, in the smallest roof slope (a equal to 20°), the frame stress was quite similar for standards adopted. On the other hand, for the greatest inclination (a equal to 26°), the stress was consistently lower under the Brazilian standard. In view of this, we came to the conclusion that the differences between stresses when applying both standards were more significant at the higher degrees of height-span ratio and roof slope.

Pesquisas sobre materiais e técnicas de construção que considerem o contexto atual de preservação do meio ambiente e de desenvolvimento socioeconômico regional sustentável estão cada vez ganhando mais espaço na sociedade. Nesse aspecto, cita-se o caso das misturas de cimento ao solo para fins de emprego como material de construção. O presente trabalho tem por objetivo geral avaliar o solo da região do Arenito Caiuá do Noroeste do Paraná com vistas a sua incorporação com o cimento para produção de tijolos de solo-cimento. O efeito da substituição parcial do cimento pela cinza do bagaço da cana-de-açúcar na resistência à compressão dos tijolos e na capacidade de absorção de água também é avaliado no presente trabalho. Foram produzidos tijolos vazados de solo-cimento e de solo-cimento-cinza segundo as prescrições da NBR 10833 (ABNT, 2012a), e a propriedade mecânica de resistência a compressão simples e a capacidade de absorção de água foram determinadas segundo a NBR 8492 (ABNT, 1994). As condições exigíveis para esses parâmetros, considerando-se a aplicação de tais tijolos à execução de alvenaria sem função estrutural, são avaliadas com base nas prescrições da NBR 8491 (ABNT, 2012b). Os resultados indicam que o solo da região do Arenito Caiuá pode ser utilizado como matéria-prima para a fabricação de tijolos de solo-cimento.

Research studies on materials and construction techniques that consider the current context of environmental preservation and regional sustainable socioeconomic development are increasingly gaining more space in society. In this respect, the use of mixed cement and soil for the production of construction materials must be pointed out. The main objective of this research work is to evaluate the soil of Caiuá Arenite Region in the northwest of the State of Parana, with the aim of using it for producing ecological soil-cement bricks. The effect of adding ash bagasse from sugar cane in the strength compression of bricks was also assessed in this investigation. Soil-cement hollow bricks were produced in accordance with the requirements of NBR 10833 (ABNT, 2012a) standard, and the compressive strength was evaluated according to NBR 8492 (ABNT, 1994) standard. The conditions required for those parameters in to application of such bricks for the non-structural masonry were evaluated based on the requirements of NBR 8491 (ABNT, 2012b). The results indicated that the soil from the Caiuá Arenite Region can be effectively used as raw material for the manufacture of soil-cement bricks.