Anderson R V Wolenski | Instituto Federal de Educação, Ciência e Tecnologia de Santa Catarina (original) (raw)

Papers by Anderson R V Wolenski

Research paper thumbnail of Avaliação Experimental Do Uso De Cimento CP IV e Adição De Metacaulim Em Concretos Auto-Adensáveis

Este trabalho apresenta um estudo experimental sobre o Concreto Auto-Adensavel (CAA), a fim de ve... more Este trabalho apresenta um estudo experimental sobre o Concreto Auto-Adensavel (CAA), a fim de verificar sua viabilidade com base no emprego do Cimento Portland Pozolânico e de agregados disponibilizados em Mato Grosso, no uso da adicao de Metacaulim e de aditivos superplastificantes advindos do sudeste do pais. Na etapa de dosagem foram realizados ensaios de Cone de Marsh, para a fase pasta, Ensaio de Kantro, para a fase argamassa, e ensaios na fase concreto, tais como Slump Flow, V-Funnel, J-Ring, L-Box, U-Shaped Pipe, e o ensaio de resistencia a compressao nas tres fases para obtencao dos parâmetros mecânicos. Foram elaborados concretos com relacao agua/cimento igual a 0,45, sendo utilizados dois aditivos superplastificantes que resultaram em concretos com resistencias a compressao superiores a 40 MPa. As analises dos resultados demonstraram que o processo de dosagem deste CAA foi eficaz, mediante um rigoroso controle tecnologico. Constatou-se ser possivel sua aplicacao em estruturas que necessitem de um concreto com elevadas fluidez e trabalhabilidade e a inviabilidade de sua aplicacao em situacoes que necessitem de rapida desmoldagem, como e o caso das industrias de pre-moldados.

Research paper thumbnail of Characteristic Strengths in the Compression and in the Static Bending as Parameters to Estimate Characteristic Shear Strength for Timber Design

Revista Árvore

To simplify the characterization of wood species, the Brazilian standard document ABNT NBR 7190-1... more To simplify the characterization of wood species, the Brazilian standard document ABNT NBR 7190-1 (2022) establishes the determination of mechanical properties employing the characteristic strength in the compression parallel to grain (fc0,k). This mechanical property is estimated using the linear relation given by the following expression fv0,k = 0.12·fc0,k Brazilian and European standard documents support the estimation of fv0,k using relations among properties. However, the European guidelines in the EN 384 (2019) have used the conventional characteristic strength in the static bending test (fM,k). Thus, this study aimed to investigate the efficiency of the ratio fv0,k = 0.12·fc0,k for adopting 30 hardwoods. The variance analysis results demonstrate the divergence among the experimental outcomes and those values estimated using the relation cited. Therefore, regression models at two parameters were considered to obtain more accurate estimates of fv0,k by adopting fc0,k, and fM,k ...

Research paper thumbnail of Effect of CCB Treatment and Alternative Adhesive Content on Physical and Mechanical Performance of Particleboards

Floresta e Ambiente, 2022

Research paper thumbnail of Influence of specimen dimensions in the determination of strength and modulus of elasticity in static bending of hardwoods

BioResources

In Brazil, standard ABNT NBR 7190 (1997) prescribes the determination of strength (fM) and modulu... more In Brazil, standard ABNT NBR 7190 (1997) prescribes the determination of strength (fM) and modulus of elasticity (EM) in static bending from specimens measuring 5 cm × 5 cm × 115 cm. Thus, the relationship between the test span (L) and the specimen height (h) greater than or equal to 21 (L/h ≥ 21) is respected, ensuring that the effect of shear in the calculation of displacements is negligible (Euler Bernoulli Theory). Considering the expressive number of tree species cataloged in the Brazilian Amazon Forest, any procedure that aims to facilitate the realization of experimental tests is highly desirable because it provides the knowledge of unusual species. These wood species may potentially replace woods that have been traditionally used and historically exploited. Using five hardwood species, this research aimed to verify, while maintaining constant L/h ≥ 21 ratios, the influence of specimens dimensions in the determination of fM and EM. For all species studied, the statistical ana...

Research paper thumbnail of Verificação da validade sobre a hipótese de pequenos deslocamentos em projetos de vigas de madeira

Anais do EBRAMEM, 2010

ABSTRACT RESUMO: Vigas de madeira são elementos estruturais comumente empregados na construção ci... more ABSTRACT RESUMO: Vigas de madeira são elementos estruturais comumente empregados na construção civil. O dimensionamento destes além de outros elementos estruturais requer a verificação do estado limite último e do estado limite de utilização. Em condições gerais, o projeto de vigas é desenvolvido partindo-se da premissa que a estrutura esteja restrita a pequenos deslocamentos e que o material seja solicitado dentro do regime elástico linear. A hipótese de pequenos deslocamentos implica em uma simplificação e, mais especificamente, em uma linearização da equação diferencial da elástica, cuja natureza é não-linear. Esta hipótese permite determinar a função dos deslocamentos em vigas por intermédio de procedimentos analíticos do cálculo diferencial e integral. Em se tratando da verificação do estado limite de utilização, a norma Brasileira NBR 7190-1997 prediz que o maior valor do deslocamento entre os apoios de uma viga não deva ultrapassar a razão L/200, sendo L o comprimento do vão definido entre os apoios, expresso em centímetros. Este trabalho tem como objetivo, verificar a validade da hipótese de pequenos deslocamentos em vigas de madeira do gênero Eucalyptus. Esta análise é efetuada segundo os fundamentos do Método das Diferenças Finitas e do Método de Newton Raphson. PALAVRAS-CHAVE: Vigas de madeira; método das diferenças finitas; método de Newton-Raphson.

Research paper thumbnail of Análise não linear de estruturas de concreto usando a estratégia de enriquecimento MEFG com um modelo constitutivo de microplanos

Research paper thumbnail of Viabilidade técnica-econômica para uso de concretos autoadensáveis em indústrias de pré-fabricados

Revista Técnico Científica do IFSC, Nov 9, 2021

O custo do concreto, para fins estruturais, decorre dos insumos e da mão de obra envolvida, tanto... more O custo do concreto, para fins estruturais, decorre dos insumos e da mão de obra envolvida, tanto na produção quanto em seu lançamento. As altas taxas de fluidez, autoadensamento, trabalhabilidade e melhor acabamento tornam o Concreto Autoadensável (CAA) uma alternativa viável para reduzir os custos relativos à mão de obra. Contudo, o uso de aditivos superplastificantes eleva o custo material na sua composição, quando comparado a um Concreto Convencional (CCV). Assim, esta pesquisa se desenvolve comparando os custos globais para produção de concretos com resistência à compressão média (f cm) entre 30 e 50 MPa a partir de experimentações com CAAs e um CCV de referência, com especial uso do Cimento Portland CP V-ARI, visando sua incorporação em uma indústria de pré-fabricados localizada no oeste catarinense. O custo total demonstrou que CAA de classes com f cm < 40 MPa apresentam custo médio 7,60% inferior ao CCV (f cm =33 MPa) de referência. Além disso, os custos globais não avaliaram os efeitos gerados no longo prazo como, por exemplo, a elevação da durabilidade em função da menor relação água/cimento (a /c), tornando os CAAs aqui pesquisados ainda mais competitivos.

Research paper thumbnail of Estimation of the characteristic tensile strength of the wood in the parallel direction to the grains through of probability models

For a structural design of wood within of the safety requirements, the strength for a certain mec... more For a structural design of wood within of the safety requirements, the strength for a certain mechanical request is calculated based on its characteristic value, corresponding to the 5% percentile of a given probability distribution model. The Brazilian standard NBR 7190 [1] establishes, for small samples, relations to estimate the characteristic strength of the wood, which can result in a significant difference of the values obtained when compared to a suitable probabilistic model. Considering the results of the tensile strength (fto,k) in the direction parallel to the grain for 40 different hardwood species, with 480 experimental determinations with standard moisture content (≈ 12%), were used distribution density functions (Normal, LogNormal, Weibull and Exponential) for each species, in order to determine the highest adhesion model. Once determined the values and respective models for each species, a multivariable linear regression model, based on analysis of variance (ANOVA) an...

Research paper thumbnail of Models for estimation of mechanical properties of compressive and tensile strength in the parallel direction to the grains

The mechanical strengths of wood are calculated, for safety reasons, based on their characteristi... more The mechanical strengths of wood are calculated, for safety reasons, based on their characteristic value. The Brazilian standard for timber structures establishes relationships to estimative the characteristic strength together with three forms of wood characterisation, with emphasis on the simplified procedure that allows, for usual species, obtaining the characteristic values through equations that correlate different mechanical properties. Considering the results of strengths (ƒc0; ƒt0) and of the modulus of elasticity (Ec0; Et0) on the compressive and tensile parallel to the grains of 40 hardwood species (960 experimental determinations with ≈ 12% moisture content), the precision of the relations ƒc0,k = 0,77 ∙ ƒt0,k and Ec0 = Et0 proposed by the standard were evaluated based on the analysis of variance (ANOVA). Besides the objective of evaluating such equations, linear, exponential, logarithmic and geometric regression models were adopted as an alternative proposal in the estim...

Research paper thumbnail of Hybrid wood veneer panels and particleboards for structural use

The use of wood panels has been gaining prominence in the construction industry. MDP panels do no... more The use of wood panels has been gaining prominence in the construction industry. MDP panels do not meet structural requirements, unlike OSB and plywood panels. An alternative solution to improve the use of wood particleboard is the reinforcement of wood particleboards (hybrid panels). This research study aimed to evaluate the potential of using hybrid panels made with wood particles and veneers of Pinus sp. and with castor-based bicomponent polyurethane resin, meeting the Brazilian Standard ABNT NBR 14810-2. The physical and mechanical properties results were compared with the normative requirements for OSB (EN 300) and plywood panels (DIN 68792), as well as with the results of commercial plywood OSB panels. Hybrid panels met the standard requirements for OSB and plywood commercial panels indicated for structural use. The statistical analysis indicated the superiority of the physical and mechanical properties of the hybrid panels when compared to the results of the OSB and commercia...

Research paper thumbnail of Modeling damage propagation with G/XFEM in concrete structures: computational aspects and numerical investigations (supporting materials)

The additional files to solve 2D solid mechanics problems using an OOP-based in-house code, calle... more The additional files to solve 2D solid mechanics problems using an OOP-based in-house code, called INSANE.<br>This files helps to reproduce the results shown in the paper: <b>Modeling damage propagation with G/XFEM in concrete structures: computational aspects and numerical investigations (supporting materials)</b>. Computers and Concrete (under review), 2018.

Research paper thumbnail of Relationship between stiffness properties for different mechanical demands in timber structures design projects

In Brazil, the Brazilian Standard NBR 7190 (ABNT, 1997) establishes testing methods to obtaining ... more In Brazil, the Brazilian Standard NBR 7190 (ABNT, 1997) establishes testing methods to obtaining the physical and mechanical properties wood. With the impossibility of determining the experimental results, the Brazilian Code establishes relations among the properties. However, the relations between the stiffness properties are based on the older normative standard MB-26: 1940 (Brazilian Standard NBR 6230), which condisidered another calculation model rather than the one used by the Brazilian standard. This research aimed to investigate the equivalence between the conventional modulus of elasticity in static bending tests (EM), with compression parallel to the fibres (Ec0) and tension parallel to the fibres (Et0) of ten species of tropical wood, as well as to establish relations between these properties, in case they are not equivalent. The ANOVA results showed that Ec0 and Et0 were statistically equivalent, and the relation between EM and 0.90∙Ec0 was not statistically equivalent, i...

Research paper thumbnail of Estudo De Viabilidade Técnica e Econômica Entre Os Concretos Autoadensável e Convencional

Força, Crescimento e Qualidade da Engenharia Civil no Brasil 2, 2021

Research paper thumbnail of Influence of provenance on physical and mechanical properties of Angelim-pedra (Hymenolobium petraeum Ducke.) wood species

European Journal of Wood and Wood Products, 2021

This research aims to investigate, with the aid of the Brazilian standard NBR 7190, analysis of v... more This research aims to investigate, with the aid of the Brazilian standard NBR 7190, analysis of variance (ANOVA—5% significance) and the regrouping bootstrap technique, the influence of the provenance regions Bonfim, Mucajai and Claudia on the physical and mechanical properties (twenty properties and 720 determinations) of Angelim-pedra (Hymenolobium petraeum Ducke.) and to assess the possibility of estimating, via regression models (152 in all), the physical and mechanical properties investigated as a function of apparent density (ρ12) and compressive strength parallel to the grain (fc0). The results indicated equivalence in most of the physical and mechanical properties, evidencing the small influence of the tree harvest regions. From the regression models, some were considered significant by ANOVA (at the 5% level of significance), which implies that variations in ρ12 and fc0 explain variations in the values of the other estimated properties; however, the low precision indicates that it is not feasible to estimate the variables just based on the ρ12 or fc0.

Research paper thumbnail of Investigação Numérica Da Importância De Armaduras De Fretagem Em Vigas Pós-Tracionadas Não Aderentes

HOLOS, 2020

No concreto protendido, em razão da aplicação da força de protensão, a região das ancoragens é su... more No concreto protendido, em razão da aplicação da força de protensão, a região das ancoragens é submetida à elevadas tensões. Ao longo de um trecho, denominado comprimento de regularização, a distribuição dessas tensões não é uniforme, estando a tensão de compressão, atuante na direção longitudinal do elemento estrutural, acompanhada de tensões nas direções transversais. Para resistir aos esforços transversais de tração, faz-se necessário a adoção de armaduras complementares, denominadas armaduras de fretagem, comumente utilizadas na forma de espirais, estribos secundários ou a combinação de ambos. Neste contexto, este trabalho teve como objetivo investigar o comportamento e a distribuição de tensões ao longo do comprimento de regularização de elementos protendidos, avaliando numericamente no software Abaqus® a influência e importância de armaduras de fretagem em tais elementos. Para tanto, foram simulados dois modelos numéricos, VE e VEF, com mesma quantidade de armadura longitudina...

Research paper thumbnail of Chemical evaluation of two tropical wood species for use as grilling planks

BioResources, 2021

This research evaluated the possible use of tropical hardwood species (Myrocarpus frondosus and O... more This research evaluated the possible use of tropical hardwood species (Myrocarpus frondosus and Ocotea porosa) for grilling plank production. Physical, chemical, and organoleptic properties were evaluated and compared with properties of a well-used wood species for grilling planks, western red cedar (Thuja plicata). For chemical analysis, one technique was used: hydrodistillation. Normality tests and analyses of variance (ANOVA) were used for the comparisons between Thuja plicata and tropical hardwoods. The results of the organoleptic, chemical, and statistical analyses demonstrated the possibility of using Myrocarpus frondosus and Ocotea porosa in grilling plank production.

Research paper thumbnail of Models to estimate longitudinal compressive strength of Brazilian hardwood based on apparent density

BioResources, 2021

As wood is an orthotropic and natural material, there are several properties required for its use... more As wood is an orthotropic and natural material, there are several properties required for its use in civil construction. The apparent density has been used to estimate physical and mechanical properties of wood, as it is easy to determine experimentally, unlike other determinations, which involve the use of equipment available only in large research centers. Using the Brazilian standard ABNT NBR 7190 and linear and non-linear regression models, this research aimed to evaluate their accuracy in estimating the compressive strength parallel to the fibers (fc0) as well as their characteristic value (fc0,k). This study considered 72 tropical wood species from native forests that were divided into the 4 strength classes of this standard. For the set formed by all species, the linear polynomial model was the best fit, resulting in a determination coefficient of just over 70%.

Research paper thumbnail of Analysis of relations between the moduli of elasticity in compression, tension, and static bending of hardwoods

BioResources, 2020

Accurate estimation of average modulus of elasticity in compression parallel to the grain (Ec0) i... more Accurate estimation of average modulus of elasticity in compression parallel to the grain (Ec0) is of paramount importance for rational sizing of timber structures, given the use of this property in the estimation of stability of compressed parts (ultimate limit state, ULS) and in calculation of excessive strains (serviceability limit state, SLS). In Brazil, if values cannot be experimentally determined, ABNT NBR 7190 (1997) allows for estimation of Ec0 through relations to average modulus of elasticity both in tension parallel to the grain (Et0) (Ec0 = Et0) and in bending (EM) (Ec0 = EM/0.90). This research aimed to access the efficiency of these relations by testing 30 tropical wood species. The analysis of variance results showed that Ec0 and Et0 were statistically equal. However, Ec0 and EM/0.90 were not statistically equal, and the method of least squares resulted in a coefficient of 0.98, which was 8.89% higher than the one suggested by ABNT NBR 7190 (1997) and close to 1, thu...

Research paper thumbnail of Influence of Stiffness Related to the C40 Strength Class of the Hardwood Group Established by the Brazilian Standard in the Design of Timber Structures

WOOD RESEARCH 66(4) 2021, 2021

The Brazilian standard ABNT 7190 (1997) establishes the strength classes C20, C30, C40 and C60 fo... more The Brazilian standard ABNT 7190 (1997) establishes the strength classes C20, C30, C40 and C60 for the proper framework of the different wood types in the group of hardwoods. Associated with the strength class, which is based on the compressive strength characteristic value parallel to the fibers (fc0,k), the standard stipulates the respective values representing the stiffness (Ec0), with 19500 MPa being the reference value for the class C40, essential variables in structural design. For being the C40 class is the one with the greatest amplitude (20 MPa), it is possible that the value 19500 MPa is not the best representation of stiffness. This work aimed to verify the representativeness the stiffness value established by the Brazilian standard for C40 wood. The result obtained from the average confidence interval indicates the value of 14110 MPa as being the most representative, which may imply structures that are supposedly more rigid than they really are.

Research paper thumbnail of Estados limites determinantes no dimensionamento da armadura longitudinal de vigas pós-tracionadas sem aderência

Revista Principia - Divulgação Científica e Tecnológica do IFPB, 2020

No dimensionamento de elementos estruturais em concreto protendido, pelo fato da protensão introd... more No dimensionamento de elementos estruturais em concreto protendido, pelo fato da protensão introduzir ações na estrutura, os estados limites de serviço de formação de fissuras (ELS-F), descompressão (ELS-D), e o estado limite último no ato da protensão (ELU-ATO) são determinantes no dimensionamento da armadura longitudinal (Ap). Comumente, a armadura necessária para atender a todos os estados limites não é exata, sendo a solução, caso exista, compreendida em um intervalo de valores definido pelos limites de tensão do ELS-F, ELS-D e ELU-ATO. Neste contexto, este trabalho objetivou verificar, analiticamente, os estados limites, de serviço ou últimos, determinantes no cálculo de Ap de vigas pós-tracionadas sem aderência. Para tanto, analisou-se vigas com propriedades dos materiais, condições ambientais, largura da seção transversal e carregamentos idênticos (exceto o peso próprio), variando a altura entre 50 e 70 cm. Constatou-se que os limites de tensão de tração no ELS-D e de compres...

Research paper thumbnail of Avaliação Experimental Do Uso De Cimento CP IV e Adição De Metacaulim Em Concretos Auto-Adensáveis

Este trabalho apresenta um estudo experimental sobre o Concreto Auto-Adensavel (CAA), a fim de ve... more Este trabalho apresenta um estudo experimental sobre o Concreto Auto-Adensavel (CAA), a fim de verificar sua viabilidade com base no emprego do Cimento Portland Pozolânico e de agregados disponibilizados em Mato Grosso, no uso da adicao de Metacaulim e de aditivos superplastificantes advindos do sudeste do pais. Na etapa de dosagem foram realizados ensaios de Cone de Marsh, para a fase pasta, Ensaio de Kantro, para a fase argamassa, e ensaios na fase concreto, tais como Slump Flow, V-Funnel, J-Ring, L-Box, U-Shaped Pipe, e o ensaio de resistencia a compressao nas tres fases para obtencao dos parâmetros mecânicos. Foram elaborados concretos com relacao agua/cimento igual a 0,45, sendo utilizados dois aditivos superplastificantes que resultaram em concretos com resistencias a compressao superiores a 40 MPa. As analises dos resultados demonstraram que o processo de dosagem deste CAA foi eficaz, mediante um rigoroso controle tecnologico. Constatou-se ser possivel sua aplicacao em estruturas que necessitem de um concreto com elevadas fluidez e trabalhabilidade e a inviabilidade de sua aplicacao em situacoes que necessitem de rapida desmoldagem, como e o caso das industrias de pre-moldados.

Research paper thumbnail of Characteristic Strengths in the Compression and in the Static Bending as Parameters to Estimate Characteristic Shear Strength for Timber Design

Revista Árvore

To simplify the characterization of wood species, the Brazilian standard document ABNT NBR 7190-1... more To simplify the characterization of wood species, the Brazilian standard document ABNT NBR 7190-1 (2022) establishes the determination of mechanical properties employing the characteristic strength in the compression parallel to grain (fc0,k). This mechanical property is estimated using the linear relation given by the following expression fv0,k = 0.12·fc0,k Brazilian and European standard documents support the estimation of fv0,k using relations among properties. However, the European guidelines in the EN 384 (2019) have used the conventional characteristic strength in the static bending test (fM,k). Thus, this study aimed to investigate the efficiency of the ratio fv0,k = 0.12·fc0,k for adopting 30 hardwoods. The variance analysis results demonstrate the divergence among the experimental outcomes and those values estimated using the relation cited. Therefore, regression models at two parameters were considered to obtain more accurate estimates of fv0,k by adopting fc0,k, and fM,k ...

Research paper thumbnail of Effect of CCB Treatment and Alternative Adhesive Content on Physical and Mechanical Performance of Particleboards

Floresta e Ambiente, 2022

Research paper thumbnail of Influence of specimen dimensions in the determination of strength and modulus of elasticity in static bending of hardwoods

BioResources

In Brazil, standard ABNT NBR 7190 (1997) prescribes the determination of strength (fM) and modulu... more In Brazil, standard ABNT NBR 7190 (1997) prescribes the determination of strength (fM) and modulus of elasticity (EM) in static bending from specimens measuring 5 cm × 5 cm × 115 cm. Thus, the relationship between the test span (L) and the specimen height (h) greater than or equal to 21 (L/h ≥ 21) is respected, ensuring that the effect of shear in the calculation of displacements is negligible (Euler Bernoulli Theory). Considering the expressive number of tree species cataloged in the Brazilian Amazon Forest, any procedure that aims to facilitate the realization of experimental tests is highly desirable because it provides the knowledge of unusual species. These wood species may potentially replace woods that have been traditionally used and historically exploited. Using five hardwood species, this research aimed to verify, while maintaining constant L/h ≥ 21 ratios, the influence of specimens dimensions in the determination of fM and EM. For all species studied, the statistical ana...

Research paper thumbnail of Verificação da validade sobre a hipótese de pequenos deslocamentos em projetos de vigas de madeira

Anais do EBRAMEM, 2010

ABSTRACT RESUMO: Vigas de madeira são elementos estruturais comumente empregados na construção ci... more ABSTRACT RESUMO: Vigas de madeira são elementos estruturais comumente empregados na construção civil. O dimensionamento destes além de outros elementos estruturais requer a verificação do estado limite último e do estado limite de utilização. Em condições gerais, o projeto de vigas é desenvolvido partindo-se da premissa que a estrutura esteja restrita a pequenos deslocamentos e que o material seja solicitado dentro do regime elástico linear. A hipótese de pequenos deslocamentos implica em uma simplificação e, mais especificamente, em uma linearização da equação diferencial da elástica, cuja natureza é não-linear. Esta hipótese permite determinar a função dos deslocamentos em vigas por intermédio de procedimentos analíticos do cálculo diferencial e integral. Em se tratando da verificação do estado limite de utilização, a norma Brasileira NBR 7190-1997 prediz que o maior valor do deslocamento entre os apoios de uma viga não deva ultrapassar a razão L/200, sendo L o comprimento do vão definido entre os apoios, expresso em centímetros. Este trabalho tem como objetivo, verificar a validade da hipótese de pequenos deslocamentos em vigas de madeira do gênero Eucalyptus. Esta análise é efetuada segundo os fundamentos do Método das Diferenças Finitas e do Método de Newton Raphson. PALAVRAS-CHAVE: Vigas de madeira; método das diferenças finitas; método de Newton-Raphson.

Research paper thumbnail of Análise não linear de estruturas de concreto usando a estratégia de enriquecimento MEFG com um modelo constitutivo de microplanos

Research paper thumbnail of Viabilidade técnica-econômica para uso de concretos autoadensáveis em indústrias de pré-fabricados

Revista Técnico Científica do IFSC, Nov 9, 2021

O custo do concreto, para fins estruturais, decorre dos insumos e da mão de obra envolvida, tanto... more O custo do concreto, para fins estruturais, decorre dos insumos e da mão de obra envolvida, tanto na produção quanto em seu lançamento. As altas taxas de fluidez, autoadensamento, trabalhabilidade e melhor acabamento tornam o Concreto Autoadensável (CAA) uma alternativa viável para reduzir os custos relativos à mão de obra. Contudo, o uso de aditivos superplastificantes eleva o custo material na sua composição, quando comparado a um Concreto Convencional (CCV). Assim, esta pesquisa se desenvolve comparando os custos globais para produção de concretos com resistência à compressão média (f cm) entre 30 e 50 MPa a partir de experimentações com CAAs e um CCV de referência, com especial uso do Cimento Portland CP V-ARI, visando sua incorporação em uma indústria de pré-fabricados localizada no oeste catarinense. O custo total demonstrou que CAA de classes com f cm < 40 MPa apresentam custo médio 7,60% inferior ao CCV (f cm =33 MPa) de referência. Além disso, os custos globais não avaliaram os efeitos gerados no longo prazo como, por exemplo, a elevação da durabilidade em função da menor relação água/cimento (a /c), tornando os CAAs aqui pesquisados ainda mais competitivos.

Research paper thumbnail of Estimation of the characteristic tensile strength of the wood in the parallel direction to the grains through of probability models

For a structural design of wood within of the safety requirements, the strength for a certain mec... more For a structural design of wood within of the safety requirements, the strength for a certain mechanical request is calculated based on its characteristic value, corresponding to the 5% percentile of a given probability distribution model. The Brazilian standard NBR 7190 [1] establishes, for small samples, relations to estimate the characteristic strength of the wood, which can result in a significant difference of the values obtained when compared to a suitable probabilistic model. Considering the results of the tensile strength (fto,k) in the direction parallel to the grain for 40 different hardwood species, with 480 experimental determinations with standard moisture content (≈ 12%), were used distribution density functions (Normal, LogNormal, Weibull and Exponential) for each species, in order to determine the highest adhesion model. Once determined the values and respective models for each species, a multivariable linear regression model, based on analysis of variance (ANOVA) an...

Research paper thumbnail of Models for estimation of mechanical properties of compressive and tensile strength in the parallel direction to the grains

The mechanical strengths of wood are calculated, for safety reasons, based on their characteristi... more The mechanical strengths of wood are calculated, for safety reasons, based on their characteristic value. The Brazilian standard for timber structures establishes relationships to estimative the characteristic strength together with three forms of wood characterisation, with emphasis on the simplified procedure that allows, for usual species, obtaining the characteristic values through equations that correlate different mechanical properties. Considering the results of strengths (ƒc0; ƒt0) and of the modulus of elasticity (Ec0; Et0) on the compressive and tensile parallel to the grains of 40 hardwood species (960 experimental determinations with ≈ 12% moisture content), the precision of the relations ƒc0,k = 0,77 ∙ ƒt0,k and Ec0 = Et0 proposed by the standard were evaluated based on the analysis of variance (ANOVA). Besides the objective of evaluating such equations, linear, exponential, logarithmic and geometric regression models were adopted as an alternative proposal in the estim...

Research paper thumbnail of Hybrid wood veneer panels and particleboards for structural use

The use of wood panels has been gaining prominence in the construction industry. MDP panels do no... more The use of wood panels has been gaining prominence in the construction industry. MDP panels do not meet structural requirements, unlike OSB and plywood panels. An alternative solution to improve the use of wood particleboard is the reinforcement of wood particleboards (hybrid panels). This research study aimed to evaluate the potential of using hybrid panels made with wood particles and veneers of Pinus sp. and with castor-based bicomponent polyurethane resin, meeting the Brazilian Standard ABNT NBR 14810-2. The physical and mechanical properties results were compared with the normative requirements for OSB (EN 300) and plywood panels (DIN 68792), as well as with the results of commercial plywood OSB panels. Hybrid panels met the standard requirements for OSB and plywood commercial panels indicated for structural use. The statistical analysis indicated the superiority of the physical and mechanical properties of the hybrid panels when compared to the results of the OSB and commercia...

Research paper thumbnail of Modeling damage propagation with G/XFEM in concrete structures: computational aspects and numerical investigations (supporting materials)

The additional files to solve 2D solid mechanics problems using an OOP-based in-house code, calle... more The additional files to solve 2D solid mechanics problems using an OOP-based in-house code, called INSANE.<br>This files helps to reproduce the results shown in the paper: <b>Modeling damage propagation with G/XFEM in concrete structures: computational aspects and numerical investigations (supporting materials)</b>. Computers and Concrete (under review), 2018.

Research paper thumbnail of Relationship between stiffness properties for different mechanical demands in timber structures design projects

In Brazil, the Brazilian Standard NBR 7190 (ABNT, 1997) establishes testing methods to obtaining ... more In Brazil, the Brazilian Standard NBR 7190 (ABNT, 1997) establishes testing methods to obtaining the physical and mechanical properties wood. With the impossibility of determining the experimental results, the Brazilian Code establishes relations among the properties. However, the relations between the stiffness properties are based on the older normative standard MB-26: 1940 (Brazilian Standard NBR 6230), which condisidered another calculation model rather than the one used by the Brazilian standard. This research aimed to investigate the equivalence between the conventional modulus of elasticity in static bending tests (EM), with compression parallel to the fibres (Ec0) and tension parallel to the fibres (Et0) of ten species of tropical wood, as well as to establish relations between these properties, in case they are not equivalent. The ANOVA results showed that Ec0 and Et0 were statistically equivalent, and the relation between EM and 0.90∙Ec0 was not statistically equivalent, i...

Research paper thumbnail of Estudo De Viabilidade Técnica e Econômica Entre Os Concretos Autoadensável e Convencional

Força, Crescimento e Qualidade da Engenharia Civil no Brasil 2, 2021

Research paper thumbnail of Influence of provenance on physical and mechanical properties of Angelim-pedra (Hymenolobium petraeum Ducke.) wood species

European Journal of Wood and Wood Products, 2021

This research aims to investigate, with the aid of the Brazilian standard NBR 7190, analysis of v... more This research aims to investigate, with the aid of the Brazilian standard NBR 7190, analysis of variance (ANOVA—5% significance) and the regrouping bootstrap technique, the influence of the provenance regions Bonfim, Mucajai and Claudia on the physical and mechanical properties (twenty properties and 720 determinations) of Angelim-pedra (Hymenolobium petraeum Ducke.) and to assess the possibility of estimating, via regression models (152 in all), the physical and mechanical properties investigated as a function of apparent density (ρ12) and compressive strength parallel to the grain (fc0). The results indicated equivalence in most of the physical and mechanical properties, evidencing the small influence of the tree harvest regions. From the regression models, some were considered significant by ANOVA (at the 5% level of significance), which implies that variations in ρ12 and fc0 explain variations in the values of the other estimated properties; however, the low precision indicates that it is not feasible to estimate the variables just based on the ρ12 or fc0.

Research paper thumbnail of Investigação Numérica Da Importância De Armaduras De Fretagem Em Vigas Pós-Tracionadas Não Aderentes

HOLOS, 2020

No concreto protendido, em razão da aplicação da força de protensão, a região das ancoragens é su... more No concreto protendido, em razão da aplicação da força de protensão, a região das ancoragens é submetida à elevadas tensões. Ao longo de um trecho, denominado comprimento de regularização, a distribuição dessas tensões não é uniforme, estando a tensão de compressão, atuante na direção longitudinal do elemento estrutural, acompanhada de tensões nas direções transversais. Para resistir aos esforços transversais de tração, faz-se necessário a adoção de armaduras complementares, denominadas armaduras de fretagem, comumente utilizadas na forma de espirais, estribos secundários ou a combinação de ambos. Neste contexto, este trabalho teve como objetivo investigar o comportamento e a distribuição de tensões ao longo do comprimento de regularização de elementos protendidos, avaliando numericamente no software Abaqus® a influência e importância de armaduras de fretagem em tais elementos. Para tanto, foram simulados dois modelos numéricos, VE e VEF, com mesma quantidade de armadura longitudina...

Research paper thumbnail of Chemical evaluation of two tropical wood species for use as grilling planks

BioResources, 2021

This research evaluated the possible use of tropical hardwood species (Myrocarpus frondosus and O... more This research evaluated the possible use of tropical hardwood species (Myrocarpus frondosus and Ocotea porosa) for grilling plank production. Physical, chemical, and organoleptic properties were evaluated and compared with properties of a well-used wood species for grilling planks, western red cedar (Thuja plicata). For chemical analysis, one technique was used: hydrodistillation. Normality tests and analyses of variance (ANOVA) were used for the comparisons between Thuja plicata and tropical hardwoods. The results of the organoleptic, chemical, and statistical analyses demonstrated the possibility of using Myrocarpus frondosus and Ocotea porosa in grilling plank production.

Research paper thumbnail of Models to estimate longitudinal compressive strength of Brazilian hardwood based on apparent density

BioResources, 2021

As wood is an orthotropic and natural material, there are several properties required for its use... more As wood is an orthotropic and natural material, there are several properties required for its use in civil construction. The apparent density has been used to estimate physical and mechanical properties of wood, as it is easy to determine experimentally, unlike other determinations, which involve the use of equipment available only in large research centers. Using the Brazilian standard ABNT NBR 7190 and linear and non-linear regression models, this research aimed to evaluate their accuracy in estimating the compressive strength parallel to the fibers (fc0) as well as their characteristic value (fc0,k). This study considered 72 tropical wood species from native forests that were divided into the 4 strength classes of this standard. For the set formed by all species, the linear polynomial model was the best fit, resulting in a determination coefficient of just over 70%.

Research paper thumbnail of Analysis of relations between the moduli of elasticity in compression, tension, and static bending of hardwoods

BioResources, 2020

Accurate estimation of average modulus of elasticity in compression parallel to the grain (Ec0) i... more Accurate estimation of average modulus of elasticity in compression parallel to the grain (Ec0) is of paramount importance for rational sizing of timber structures, given the use of this property in the estimation of stability of compressed parts (ultimate limit state, ULS) and in calculation of excessive strains (serviceability limit state, SLS). In Brazil, if values cannot be experimentally determined, ABNT NBR 7190 (1997) allows for estimation of Ec0 through relations to average modulus of elasticity both in tension parallel to the grain (Et0) (Ec0 = Et0) and in bending (EM) (Ec0 = EM/0.90). This research aimed to access the efficiency of these relations by testing 30 tropical wood species. The analysis of variance results showed that Ec0 and Et0 were statistically equal. However, Ec0 and EM/0.90 were not statistically equal, and the method of least squares resulted in a coefficient of 0.98, which was 8.89% higher than the one suggested by ABNT NBR 7190 (1997) and close to 1, thu...

Research paper thumbnail of Influence of Stiffness Related to the C40 Strength Class of the Hardwood Group Established by the Brazilian Standard in the Design of Timber Structures

WOOD RESEARCH 66(4) 2021, 2021

The Brazilian standard ABNT 7190 (1997) establishes the strength classes C20, C30, C40 and C60 fo... more The Brazilian standard ABNT 7190 (1997) establishes the strength classes C20, C30, C40 and C60 for the proper framework of the different wood types in the group of hardwoods. Associated with the strength class, which is based on the compressive strength characteristic value parallel to the fibers (fc0,k), the standard stipulates the respective values representing the stiffness (Ec0), with 19500 MPa being the reference value for the class C40, essential variables in structural design. For being the C40 class is the one with the greatest amplitude (20 MPa), it is possible that the value 19500 MPa is not the best representation of stiffness. This work aimed to verify the representativeness the stiffness value established by the Brazilian standard for C40 wood. The result obtained from the average confidence interval indicates the value of 14110 MPa as being the most representative, which may imply structures that are supposedly more rigid than they really are.

Research paper thumbnail of Estados limites determinantes no dimensionamento da armadura longitudinal de vigas pós-tracionadas sem aderência

Revista Principia - Divulgação Científica e Tecnológica do IFPB, 2020

No dimensionamento de elementos estruturais em concreto protendido, pelo fato da protensão introd... more No dimensionamento de elementos estruturais em concreto protendido, pelo fato da protensão introduzir ações na estrutura, os estados limites de serviço de formação de fissuras (ELS-F), descompressão (ELS-D), e o estado limite último no ato da protensão (ELU-ATO) são determinantes no dimensionamento da armadura longitudinal (Ap). Comumente, a armadura necessária para atender a todos os estados limites não é exata, sendo a solução, caso exista, compreendida em um intervalo de valores definido pelos limites de tensão do ELS-F, ELS-D e ELU-ATO. Neste contexto, este trabalho objetivou verificar, analiticamente, os estados limites, de serviço ou últimos, determinantes no cálculo de Ap de vigas pós-tracionadas sem aderência. Para tanto, analisou-se vigas com propriedades dos materiais, condições ambientais, largura da seção transversal e carregamentos idênticos (exceto o peso próprio), variando a altura entre 50 e 70 cm. Constatou-se que os limites de tensão de tração no ELS-D e de compres...

Research paper thumbnail of Estimation model of mechanical properties from the compressive strength values

To ensure the safety of wooden structures, estimation of wood strength is based on the characteri... more To ensure the safety of wooden structures, estimation of wood strength is based on the characteristic strength values. The Brazilian standard (NBR, in Portuguese Norma Brasileira Regulamentadora) 7190 proposes equations to estimate the strength properties with a simplified procedure, which allows obtaining the characteristic values through relations that correlate different mechanical properties. Using these equations, the values of tensile (f t0,k) and shear (f v0,k) strength can be calculated in a simplified way from the compressive strength (f c0,k) values. In the present work, 36 tropical hardwood species were evaluated for tensile, shear and compressive strength in the direction parallel to the grain, with a total of 1296 experimental measurements, and the precision of the relations defined by the Brazilian standard was assessed using the analysis of variance (ANOVA) method. Two-parameter regression models, based on linear, exponential, logarithmic and geometric functions, were used as an alternative proposal for the estimation of the strength properties. The statistical analysis validated the proposed relations, with the linear (f t0,k) and geometric (f v0,k) regression models being the models of best fit, with the coefficients of determination (R 2) equal to 63,02 % and 70,15 %, respectively. In addition, new simplified equations were suggested. The least squares method was used to determine the optimal coefficient (α) for validation of the Brazilian standard equations. The obtained coefficients validated the tensile strength relationship (f t0,k = f c0,k / 0,77), but failed to validate the shear strength relationship (f v0,k = 0,12• f c0,k). In the latter case, the obtained values were significantly higher (up to 91 % higher) when compared to those estimated by the Standard.