Abstract Columns are important structural elements in a building and can be reinforced to increase their capacity. Reinforcement by bonding Fiber Reinforced Polymers (FRP) is attractive because it is easy to apply and does not modify the section. This material has been used in columns for its confinement effect. However, the confinement of columns in non-circular sections is not as efficient as in circular ones. Non-circular geometries behave differently because part of the concrete is not confined. This research aims to study the behavior of rectangular concrete columns reinforced with carbon fiber mats. The aim is to evaluate the performance of rectangular columns with a section side ratio of 2 and to determine the efficiency of the reinforcement. Two groups of columns were tested, one without reinforcement and the other reinforced with a layer of mat. Numerical models were designed with the Finite Element Method (FEM) using Abaqus. The numerical model made it possible to analyze the distribution of stresses in the pillars. Experimental results of maximum force were compared with analytical predictions. The results obtained indicate the efficiency of the reinforcement by improving ductility and increasing load capacity by 30%. FRP (FRP effect However noncircular non ones Noncircular Non confined mats tested mat FEM (FEM Abaqus pillars predictions 30 30% 3

Resumo Pilares são elementos estruturais de grande importância numa edificação e que durante sua vida útil podem ser submetidos a um processo de reforço para aumento da sua capacidade. O reforço com Polímeros Reforçados com Fibras (PRF) é atraente pela facilidade de aplicação e não modificação da seção. O material vem sendo utilizado em pilares pelo efeito de confinamento. Entretanto, em pilares com seções não circulares, o efeito do confinamento não é eficiente como em circulares. Em geometrias de seções não circulares, parte do concreto não fica devidamente confinado. A pesquisa busca estudar o comportamento do reforço de pilares de concreto retangulares pelo confinamento com manta de fibras de carbono. O objetivo é avaliar o desempenho e a eficiência do reforço em pilares retangulares não armados, com altura de 800 mm e relação entre os lados igual a 2. Foram ensaiados dois grupos de pilares, um sem reforço e outro reforçado. Foram idealizados modelos numéricos com o Método dos Elementos Finitos utilizando-se o Abaqus. O modelo numérico permitiu analisar a distribuição das tensões nos pilares. Os resultados experimentais de força máxima foram comparados com previsões analíticas. Os resultados obtidos indicam eficiência do reforço por meio de melhoria na ductilidade e aumento da capacidade de carga em 30%. PRF (PRF seção Entretanto circulares confinado carbono armados 80 2 reforçado utilizandose utilizando se Abaqus analíticas 30 30% 8 3

Replacing traditional stirrups with high-strength rectangular spiral stirrups can improve the seismic performance of reinforced concrete columns. In order to study the seismic performance of high-strength spiral stirrup confined concrete columns, a validated finite element (FE) method was proposed to establish the FE model of reinforced concrete columns. Combined with the measured data of two existing specimens, parameter analysis was conducted on 19 specimens. The axial compression ratio, shear span ratio, stirrup spacing, and stirrup diameter were variable parameters. Based on a reliable model, internal stress analysis was conducted, and the influence of different variables on the seismic performance of reinforced concrete columns was revealed. The FE results suggest that, when the axial compression ratio is not greater than 0.6, the requirement of ductility greater than 3 in the Chinese Standard GB 50011-2010 can be met. The recommended shear span ratio for optimal ductility was around 4.5. The reinforcement ratio of high-strength spiral stirrups ranges from 1.0% to 2.2%. After completing the simulation of nearly 100 specimens (only calculating the ductility coefficient), a matching relationship between the axial compression ratio limit and the shear span ratio was proposed.

Abstract: This investigation compared the efficiency of a flat-plate solar collector with triangular and square geometry, by using the finite element method (FEM). The design of the geometries and the utilized parameters for the simulation were obtained from previous publications. SolidWorks was used to model the two collectors, meanwhile, the Fluent module of the ANSYS software was used for the simulation by the FEM. Collectors integrated a pipe of 7 mm internal diameter with a plate thickness of 11 mm; the defined material was aluminum. The experiment was conducted under ambient conditions at a temperature of 20 °C, accompanied by a solar radiation intensity of 1000 W·m-2. The heat transfer surfaces employed were 61 250 mm2 for the triangular collector and 122 500 mm2 for the square collector. The quality of the mesh was excellent, obtaining a skewness of 0.2486, with which efficiencies of 62 and 39 % and maximum temperatures of 27 and 25.5 °C were obtained for the triangular and square collectors, respectively. Due to the geometries performing as fins, the temperatures are higher in the corners and, therefore, achieving higher efficiency is impossible.

Resumen: En esta investigación, se comparó la eficiencia de un colector solar de placa plana con geometría triangular y cuadrada, a través del enfoque del método de elementos finitos (FEM, por sus siglas en inglés), se llevó a cabo la simulación. Las geometrías y los parámetros empleados en la simulación fueron extraídos de investigaciones previamente publicadas. Se utilizó el software SolidWorks para el modelado de los dos colectores, mientras que el módulo Fluent del software ANSYS fue utilizado para la simulación por el método FEM. Para los colectores se utilizó una tubería de 7 mm de diámetro interno, con un espesor de placa de 11 mm y de aluminio. Se consideró temperatura ambiente de 20 °C, con una radiación solar de 1000 W·m-2 y superficies de transferencia de calor 61 250 y 122 500 mm2 para el colector triangular y cuadrado, respectivamente. La calidad del mallado fue excelente, alcanzando skewness de 0.2486. De esta manera, luego del proceso de simulación se obtuvo eficiencias de 62 y 39 % y temperaturas máximas de 27 y 25.5 °C para el colector triangular y cuadrado, respectivamente. Debido a que las geometrías actúan como aletas, las temperaturas son más altas en las esquinas y por esto no es posible alcanzar mayor eficiencia.

Abstract: Recent applications demonstrated how fiber-reinforced polymer (FRP) composites can improve the structural capabilities of glulam beams, particularly regarding their flexural and shear strength. With the development of precise numerical models, such systems can be optimized. There is currently a dearth of information in the literature on numerical models that can accurately anticipate the nonlinear behavior of low-grade glued laminated timber beams reinforced with FRP. In this study, larch beams were reinforced with carbon fiber reinforced polymer fabric 1, 2 and 3 layers. The effect of the number of floors on the flexural properties of the beams in reinforcement was investigated experimentally and numerically. As a result of the study, the best flexural properties were achieved with 3-layer reinforcement. It was observed that 1- and 2-layer reinforcement compared to the reference beam were also significantly effective. Numerical analyzes gave close values with experimental test results. As a result of comparing the results obtained from the numerical model with the experimental findings, it was concluded that the FRP fabric managed to significantly increase the performance of larch timber. The model is a useful tool for examining the effect of reinforcement coefficient and will be used for optimization of the larch beam

Abstract: Steel fiber reinforced concrete, compared to the conventional concrete; is a composite building material that performs much better in terms of parameters such as ductility, energy absorption capacity, fracture toughness, fatigue resistance, and the use of steel fiber reinforced concrete (SFRC) in structures has become widespread. In this study, a nonlinear finite element model (FEM) has been developed that can represent the behavior of beams produced by using steel fiber concrete subjected to impact load. For this purpose, a finite element model of beam series produced with fiber-reinforced concrete obtained from the literature was created. The ABAQUS package program was used to create models simulating the behavior. Numerical results showed that the model could successfully capture the experimental results of beams selected from the literature. In addition to simulation, a parametric study was also performed to investigate the effect of stirrups, reinforcement ratio, and drop height on the behavior of SFRC beams under impact loads. The results of the parametric study showed that increasing the fiber ratio and reinforcement ratio positively affected the behavior of SFRC beams in terms of displacement recovery

Abstract: This paper describes the implementation of a two-dimensional rotating smeared crack model within the framework of a nonlinear finite element analysis code, and its application to the mechanical behavior of the plain concrete. In this work, the formulation of three concrete softening law subjected to fracture Mode-I is adapted, considering infinitesimal strains, static loads and two-dimensional conditions. The rotating smeared crack model and the three softening laws are all implemented in Fortran language, into the open source software for nonlinear finite element analysis HYPLAS. The pre- and post-process for a graphical representation of the mesh and the results are done with GMSH or GiD. Finally, three experimental tests of concrete beams of other authors are simulated. The concentration of the displacement contour lines obtained in the simulation represents the crack patterns in the solid. The relationship between the applied load and the representative displacement in each analysis step describes the mechanical response of the beam. Other computed parameters were the crack opening and the principal stresses in the solid. The numerical results were satisfactory in comparison with the experimental tests.

Resumen: Este artículo describe la implementación de un modelo bidimensional de fisura distribuida rotante en el marco del análisis no-lineal mediante el método de los elementos finitos, y su aplicación al comportamiento mecánico del concreto simple. En este trabajo se adapta la formulación general del modelo de fisura distribuida rotante para tres leyes de ablandamiento del concreto en modo I de fractura, considerando deformaciones infinitesimales, cargas estáticas y estado plano de esfuerzos o de deformaciones. Asimismo, se implementa un modelo constitutivo de fisuración distribuida y tres leyes de ablandamiento en lenguaje Fortran, dentro del programa a código abierto de análisis no-lineal por elementos finitos HYPLAS. El preproceso de mallado del dominio y el postproceso de presentación gráfica de los resultados se realiza con los programas GMSH o GiD. Finalmente, se simulan tres ensayos experimentales de vigas de concreto realizados por otros autores. La concentración de líneas de contorno del desplazamiento obtenidas en la simulación representan el patrón de fisuración en el sólido. Por otro lado, la relación entre la carga aplicada y el desplazamiento representativo en cada paso de análisis describe la respuesta mecánica de la viga. Otras entidades calculadas fueron la apertura de fisura y los esfuerzos principales en el sólido. Los resultados numéricos fueron satisfactorios en comparación con los ensayos experimentales.

RESUMEN Esta investigación se centra en la evaluación de la simetría estructural del puente Zamora-Loja, una infraestructura crucial para las áreas de Loja y Zamora. Dada la preocupación por vibraciones excesivas, se llevaron a cabo ensayos geofísicos meticulosos. El objetivo principal fue analizar la respuesta del puente a diversas condiciones de carga, especialmente su simetría, esencial para la seguridad y eficiencia. Se utilizó un camión de prueba para transitar por diferentes zonas del puente, registrando variaciones reveladoras en su comportamiento. Los resultados destacaron una variación del 17.93% en el comportamiento estructural cuando el camión transitó por el carril equipado con el geófono, indicando una distribución asimétrica de la carga. En contraste, el carril sin el geófono mostró una variación del 8.82%, sugiriendo una respuesta estructural diferente. Al transitar por el carril central, la variación fue del 16.30%, reflejando una respuesta intermedia a cargas centradas. Complementando estos hallazgos, se empleó un modelo computacional basado en elementos finitos, que incorporó datos reales del puente. La comparación entre resultados reales y computacionales proporciona una perspectiva integral del comportamiento del puente, siendo una herramienta invaluable para futuras intervenciones. Estos ensayos no solo ofrecen una visión clara de la integridad y seguridad del puente, sino que también establecen un precedente para el uso de tecnologías avanzadas en la evaluación de infraestructuras críticas.

ABSTRACT This research focuses on the evaluation of the structural symmetry of the Zamora-Loja bridge, a crucial infrastructure for the Loja and Zamora areas. Given the concern for excessive vibrations, meticulous geophysical tests were carried out. The main objective was to analyze the bridge's response to various loading conditions, especially its symmetry, essential for safety and efficiency. A test truck was used to drive over different areas of the bridge, recording revealing variations in its behavior. The results highlighted a 17.93% variation in structural behavior when the truck traveled through the lane equipped with the geophone, indicating an asymmetrical load distribution. In contrast, the lane without the geophone showed a variation of 8.82%, suggesting a different structural response. When traveling in the center lane, the variation was 16.30%, reflecting an intermediate response to centered loads. Complementing these findings, a finite element based computational model was used, incorporating real bridge data. The comparison between actual and computational results provides a comprehensive perspective of the bridge behavior and is an invaluable tool for future interventions. These tests not only provide a clear view of the integrity and safety of the bridge, but also set a precedent for the use of advanced technologies in the evaluation of critical infrastructure.

We report on the development of a finite-element method model for a pilot furnace for the production of manganese alloys. The model is a multiphysics model that addresses material flow, electrical conditions, heat transfer, and physical and chemical transformations. It is capable of studying both quasi-steady and transient states in time-dependent simulations. The model includes common charge materials and fluxes and can simulate production of both ferromanganese and silicomanganese alloys with acid and basic slags, as well as changing charge compositions. The model output provides access to the material distribution in the furnace during furnace runs, temperature profiles, current paths, energy balances, and alloy and slag production rates and compositions.

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 This work aims the assessment of the dynamic structural response of reinforced concrete floors subjected to rhythmic human activities, based on the use of biodynamic models, in order to consider the people-structure interaction effect. Initially, an experimental modal analysis on the investigated floor , with dimensions of 16m x 35m, was performed, in order to identify and assess the global dynamic behaviour of the structure. In sequence, a finite element model was developed and calibrated through experimental results. After that, based on forced vibration analyses, the floor dynamic response was determined (displacements and accelerations). It is concluded that the biodynamic systems modelling induced significant attenuations on the structural response when compared to those calculated based on the use of traditional “only force” models. activities models peoplestructure people structure effect Initially m 35m performed sequence results analyses displacements accelerations. accelerations . accelerations) only force

Resumo Este trabalho tem como objetivo a avaliação da resposta dinâmica de pisos de concreto armado submetidos a atividades humanas rítmicas, com base no uso de sistemas biodinâmicos, a fim de analisar o efeito de interação pessoa-estrutura. Inicialmente, realizou-se uma análise modal experimental sobre o piso investigado, com dimensões de 16m x 35m, visando identificar e avaliar o comportamento dinâmico global da estrutura. Em seguida, um modelo de elementos finitos foi desenvolvido e calibrado com base nos resultados experimentais. Posteriormente, a partir das análises de vibração forçada, a resposta dinâmica do piso foi determinada (deslocamentos e acelerações). Conclui-se que a modelagem dos sistemas biodinâmicos induziu atenuações significativas sobre a resposta estrutural quando comparadas àquelas calculadas via utilização de modelos tradicionais de força-rítmica. rítmicas pessoaestrutura. pessoaestrutura pessoa estrutura pessoa-estrutura Inicialmente realizouse realizou se investigado m 35m seguida experimentais Posteriormente forçada deslocamentos acelerações. acelerações . acelerações) Concluise Conclui forçarítmica. forçarítmica força rítmica. rítmica força-rítmica

Abstract This paper presents a reliability analysis of the punching shear of flat slabs without shear reinforcement. The evaluation is performed for the codes ACI 318, Eurocode 2, Model Code 2010, and ABNT NBR 6118:2014. Six models were used for predicting the punching strength, the design models, the Critical Shear Crack Theory (CSCT), and a Nonlinear Finite Element Analysis (NLFEA) model. Reliability analysis was performed to evaluate the safety level of code provisions. Design code provisions were evaluated in terms of sufficient reliability criteria based on target reliability β=3.8. This target reliability was based in the Model Code 2010 criteria. This criterion represents an acceptable value level of safety in design of structures. The results showed that the reliability indexes β presented satisfactory for all slabs designed by the Model Code 2010. However, this paper also shows some of the tested slabs presented reliability index below 3.0, being the ACI 318 the code with the lowest reliability index. reinforcement 2 61182014. 61182014 6118 2014. 2014 6118:2014 strength CSCT, CSCT , (CSCT) NLFEA (NLFEA model β38 3 8 β=3.8 201 structures However 30 0 3.0 31 6118201 611 6118:201 (CSCT β3 β=3. 20 3. 611820 61 6118:20 β=3 61182 6 6118:2 β= 6118:

Resumo Este artigo apresenta a análise de confiabilidade do dimensionamento à punção de lajes lisas sem armadura de cisalhamento. A pesquisa avaliou a confiabilidade obtida pela norma ACI 318, Eurocode 2, Código Modelo 2010 e pela norma brasileira ABNT NBR 6118:2014. Para a estimativa da resistência à punção seis modelos foram estudados, os modelos das normas, a Teoria da Fissura Crítica de Cisalhamento (TFCC) e um modelo não-linear em elementos finitos. A avaliação da confiabilidade foi realizada para avaliar o nível de segurança das prescrições normativas. Para isso, o critério utilizado é baseado na comparação dos índices de confiabilidade β com o índice de confiabilidade alvo, estipulado em 3,8, conforme critério do Código Modelo 2010. Esse critério representa um valor aceitável no nível de segurança do dimensionamento da estrutura. Os resultados obtidos a partir dessa metodologia mostrou que o Código Modelo 2010 é a norma que apresenta os índices mais elevados de confiabilidade. Por outro lado, a norma ACI 318 apresentou os menores índices de confiabilidade, alcançando índices de confiabilidade menores que 3,0. cisalhamento 2 201 61182014. 61182014 6118 2014. 2014 6118:2014 estudados normas TFCC (TFCC nãolinear não linear finitos normativas isso alvo 38 3 8 3,8 estrutura lado 31 30 0 3,0 20 6118201 611 6118:201 3, 611820 61 6118:20 61182 6 6118:2 6118:

Abstract Researchers must decide on how they will model the non-linear material response in a Finite Element simulation to assess seismic vulnerability. This paper aims at giving an insight into these modelling decisions by comparing Fiber and Lumped Plasticity Finite Element Models in static and dynamic non-linear analysis in a RC frame. The methodology is based on the performance-based earthquake engineering to determine the expected damage on structures. The results indicate that both models are in good agreement with the static analysis, and when considering Extensive and Complete Damage Limit States on the dynamic analysis. The choice between them depends on the main goals of the research and resources available, since they have a significant difference in processing time. nonlinear non linear vulnerability frame performancebased performance structures available time

Resumo Pesquisadores devem decidir sobre como modelar a resposta não linear do material em uma simulação com Elementos Finitos para avaliar a vulnerabilidade sísmica. Esse trabalho pretende auxiliar nessa tomada de decisão ao comparar os modelos de Fibra e de Plasticidade Concentrada em Elementos Finitos em análises não lineares estáticas e dinâmicas de um pórtico em concreto armado. A metodologia é baseada na engenharia de desempenho sísmico (PBEE) para determinar o dano nas estruturas. Os resultados indicam que os dois modelos apresentam uma boa correspondência em uma análise estática, e ao considerar os Estados Limite de Dano Extensivo e Completo na análise dinâmica. A escolha entre os dois depende dos objetivos principais do pesquisador e dos recursos disponíveis, já que eles apresentam uma significativa diferença no tempo de processamento. sísmica armado PBEE (PBEE estruturas estática dinâmica disponíveis processamento

Abstract Alkali-silica reaction (ASR) is a deleterious expansion phenomenon affecting concrete structures worldwide. It occurs when a susceptible chemical composition of concrete components is present, and it is particularly rampant in inherently humid environments. This phenomenon is exacerbated when found in mass concrete structures such as dams and foundations. The amount of volumetric ASR strain used to be deemed as nearly constant, however, recent advances have shown that it is actually affected by the distribution of volumetric stresses. Therefore, this behavior demands an update in the numerical models that have been devised to simulate the anisotropic ASR-driven expansion. This paper deals with Saouma & Perotti’s thermo-chemo-mechanical coupled model, which has been applied in a solely mechanical manner, and updated to account for a varying volumetric strain. A simulation of the experiment that shed new light on the variation of ASR volumetric strain was then carried out with the finite element method package COMSOL. As a result, significantly smaller errors in predicted strains were attained by the updated model in comparison to the original one, and consequently, the new model poses a promising tool for a more accurate simulation of ASR expansion. Alkalisilica Alkali silica (ASR worldwide present environments foundations constant however stresses Therefore ASRdriven driven Perottis Perotti s thermochemomechanical thermo chemo manner COMSOL result one consequently

Resumo A reação álcali-agregado é um fenômeno expansivo e deletério que afeta estruturas de concreto em todo o mundo. Ela ocorre quando existe uma composição quimicamente susceptível de componentes do concreto, e é particularmente pronunciada em ambientes inerentemente úmidos. Este fenômeno é exacerbado em estruturas de concreto-massa, como represas e fundações. Anteriormente a deformação volumétrica das reações álcali-agregado era tida como quase constante, entretanto, avanços recentes mostraram que esta é, de fato, afetada pela distribuição das tensões volumétricas. Portanto, este comportamento demanda uma atualização nos modelos numéricos que foram desenvolvidos para simular a expansão anisotrópica induzida pela RAA. Este artigo lida com o modelo termo-quimo-mecânico de Saouma e Perotti, o qual foi aplicado em maneira puramente mecânica, e atualizado para uma deformação volumétrica variável. Uma simulação do experimento que que trouxe uma nova luz sobre a variação da deformação volumétrica foi então empreendida com o pacote do método de elementos finitos COMSOL. Como resultado, erros significativamente menores nas deformações preditas foram obtidos pelo modelo atualizado, em comparação com o modelo original, e, consequentemente, o novo modelo posta-se como uma simulação mais acurada da expansão devida à RAA. álcaliagregado álcali agregado mundo úmidos concretomassa, concretomassa massa, massa concreto-massa fundações constante entretanto fato volumétricas Portanto RAA termoquimomecânico termo quimo mecânico Perotti mecânica variável COMSOL resultado original consequentemente postase posta se

Abstract This article presents a parametric numerical study of the pullout behavior of headed bars embedded in concrete elements. The finite element model was developed using Abaqus software and validated to simulate the behavior of four pullout tests. The numerical results were validated against the experimental results and showed excellent agreement with the load-slip response and failure modes. Furthermore, a parametric numerical study with 23 simulations was planned to explore the influence of several variables on concrete cone failure, including concrete strength, flexural reinforcement ratio, geometry and head size, shaft diameter, and edge and group effects. The ultimate load results, failure modes, and influence on ultimate load are discussed. elements tests loadslip slip modes Furthermore 2 strength ratio size diameter effects discussed

Abstract Analytical and computational calibrations and subsequent parametric analyses were performed on the four UHPFRC beams under flexure to estimate their actual shear strength. The computational models were calibrated using different values for the CDP parameters, and a finite element mesh sensitivity study was conducted. These models predicted the experimental behavior satisfactorily, and the analytical model was also able to find the beams’ failure loads and proved to be a simple tool to estimate their behavior. The parametric analysis showed that the current beams did not require stirrups once the UHPFRC had high shear strength, and the maximum shear capacity was accurately determined. strength parameters conducted satisfactorily determined