Roberto Vasconcelos Pinheiro

Technical Feasibility Study for the Use of Alternative Timber in Latticework for Roofing with Spans between 16 and 26 Meters

Wood, a renewable source material, has been part of the progress of mankind, being widely used in construction for centuries. However, with the passage of time, new construction techniques were being applied, new materials have been rising and, in the meantime, wood was being left out, being labelled as a material with huge incidence of pathologies. That due to its empirical use without any technical knowledge regarding its physical and mechanical properties, which still happens nowadays, being used mainly for temporary purposes. In order to show the technical viability of the use of this material as a structural element, the elaboration of projects with the following characteristics was proposed: buildings with truss structures (parallel chord) type Howe (10° inclination - steel tile); 16, 18, 20, 22, 24 and 26 meters span; side openings types of the building – 1:1, 2:1, 6:1 and open; preservative treatment. Thus, it was determined the ratio of the volume of wood (m³) and the built area (m²) for timbers classes C-20 and C-30, following the NBR 7190:1997 guidelines. With the results, it is possible to assure the real possibility of using wood species C-20 and C-30 as structural material.

Shear Strength of Joints in Glued Laminated Timber: Normative Verification of Bibliography Results

Wood has long been used by man for a wide range of purposes, including the production of furniture, civil construction and structural elements. Aiming the construction industry, the use of glued laminated timber proves to be an excellent alternative to constructive technology, allowing the production of elements with different shapes and sizes. It is important that the bonded wood presents resistance to the stresses imposed on its use. This way, the present study aims to make a comparative analysis of shear strength values of Glued Laminated Timber (also called glulam) through the analysis of studies done by several authors that used different types of wood and adhesives. The results found by these authors were verified based on the ASTM-D-5751 and the Brazilian standard ABNT NBR 7190. It was concluded that the glued joints analyzed obtained satisfactory resistance according to the American standard. However, the majority did not comply with the parameters required by the Brazilian standard.

Embedment Parallel to the Grain Strength of the Schizolobium amazonicum Herb Wood Specie

Wood is one of the main raw materials used by man in several uses. It can be used in furniture and package industries, and also in components for building construction. For all these purposes, it is necessary to know the physical and mechanical properties of wood specie being used. Brazilian Code ABNT NBR 7190:1997, in its Annex B, presents methods for determining wood mechanical properties, among them the embedment parallel to grain. This property is important because it relates to the design of bolted and nailed joints in timber structures. This research aims to the experimental determination of embedment strength parallel to grain strength for Schizolobium amazonicum Herb, a wood specie recently used for structural purposes. Results showed that embedment strength for Schizolobium amazonicum Herb wood specie is lower when compared with traditional tropical essences, but sufficient for some structural applications.

Cracks Studies Case of Buildings in Sinop City - Brazil

The building structures are objects of interest in Civil Engineering, appropriate to its importance in sustaining and preserving the building. The monitoring of their behavior can occur for analyzes on structural elements, directly, or other structures for monitoring the building. Such situations encourage the improvement of new techniques for structural evaluations through measurement service elements and interpretation of monitoring data. Amid this context, the present study aims to analyze, diagnose, classify, expose the possible causes and possible solutions of the problems of the buildings studied pathological located at Sinop – MT, where the study included various types of buildings from earthen, 3, 11 e 19 pavements, as residential construction, public and private educational institutions, or for use in the construction step, all intuited with the larger scope of diseases in the municipality, identifying whether or not problems that could compromise the safety criteria, resistance and good performance of buildings.

AVALIAÇÃO DE PROPRIEDADES FÍSICAS E MECÂNICAS DE MADEIRAS DE JATOBÁ (Hymenaea stilbocarpa Hayne) COM DIFERENTES TEORES DE UMIDADE E EXTRAÍDAS DE REGIÕES DISTINTAS1

Este trabalho objetivou investigar a influencia das regioes de extracao (Municipios de Caracarai e Bonfim, Sul de Roraima; Municipio de Alta Floresta, Norte de Mato Grosso) da madeira da especie jatoba (Hymenaea stilbocarpa). Tambem, foi avaliada a influencia do teor de umidade (madeira saturada e a 12%) em 15 propriedades fisicas e mecânicas de interesse. Ao todo, foram preparados e ensaiados, segundo as prescricoes da Norma Brasileira ABNT NR 7190 (1997), 840 corpos de prova. Os resultados da analise de variância (a 5% de significância) revelaram que a regiao de extracao dos corpos de prova nao foi significativa nas propriedades fisicas e mecânicas avaliadas, pois foram obtidos valores equivalentes, independentemente da origem, aspecto altamente interessante a medida que nem sempre e possivel identificar a regiao de onde provem a madeira tropical. Essa importância e ainda maior no caso do emprego da madeira como elemento, cujos valores de referencia se encontram apontados nos anexos do referido documento normativo. Com relacao ao teor de umidade, foi observada diferenca significativa em oito das 15 propriedades avaliadas. A condicao de 12% de teor de umidade apresentou valores medios superiores a condicao saturada nas propriedades de resistencia na compressao paralela (37%), resistencia na tracao paralela (29%) e cisalhamento (36%) na direcao paralela as fibras; modulo de resistencia na flexao (26%), modulo de elasticidade na compressao paralela (9%) e 200 direcoes paralelas (35%) e normal (28%) as fibras; e inferior na densidade aparente.

AVALIAÇÃO NUMÉRICA DO MÓDULO DE ELASTICIDADE EM VIGAS ROLIÇAS DE MADEIRA DA ESPÉCIE Pinus elliottii

This research aimed to present a numerical methodology of calculation, based on the Finite Element Method and the Least Squares Method, to determine de longitudinal modulus of elasticity in structural round timber beams, considering the irregularities in the geometry of the elements by linear approximation along the finite elements. In addition with the numerical model (1D), together, two others were used, one analytical (1D simplified), which considers a single value of diameter (cylindrical geometry), measured at the midpoint of the elements, and another numerical model (3D), allows more accurately to delineate the geometry of the element, enabling check the difference between them. Therefore, the beams were evaluated according to the static three-point bending test, being tested twenty four elements of Pinus elliottii wood species, with average length of 630 cm, breast height diameter around 21 cm, green wood (satured), tape average of 6% and mean of factor form section of 0,82. The results of the confidence interval between the modulus of elasticity of the 1D numerical model (E o ) and analytical (E deq ) showed statistical equivalence between the methodologies, justified by the small taper of the elements, may be different for others tapers. The use of the longitudinal modulus of elasticity obtained from de numerical 1D model in the 3D simulations of the round timber beams lead to displacement values equivalent to those obtained in the tests, proving the efficiency of 1D numerical model, requiring less computational work.