In the last decades, the modernization in structural engineering has increased the use of steel-concrete composite and hybrid systems for slabs, when the adherence in the interface of the materials is present or not, respectively. In addition to the traditional steel deck, a similar solution for precast trussed slabs has been used for small constructions, in which a cold formed U profile acts as steel formwork before the concrete curing, resisting to self-weight of the concrete and to the construction overload. After this period, the steel profile gets incorporated to the concrete element, allowing the composite behavior of the structure, system that usually goes without additional reinforcements. This slab includes, besides concrete, a light filling material between ribs, cold formed profiles and the trussed reinforcement. Once this technology has just arrived to the construction market, there is a gap of knowledge related to its design procedure. In this context, this study aims to present a methodology to analyze the limit-states that govern the design of these slabs. A computational tool was developed to evaluate the resistance through data entry related to geometry, service loads and materials, which grants to conduct a parametric study with pre-defined geometries to obtain, as result, spans and loads. Conclusions about the maximum span without shoring and general data are also discussed. Keywords Steel-concrete composite slabs, trussed slabs, cold formed U profile, design procedure. Evaluation of the resistance of trussed slabs with steel formwork in cold formed U profile Lucas Fadini Favarato et al. Latin American Journal of Solids and Structures, 2019, 16(7 Thematic Section), e178 2/18 (2015) also states that the major advantage in the use of this structural technology is related to the fabrication process: thin plates, with small resistance in its original shape, are stiffened where buckling can occur. Hence, the folding procedure changes steel original mechanical properties, leading to highest yield and ultimate strengths. Otherwise, residual stresses may come up, reducing the ductility of the material. Whereas rolled and welded steel profiles are more suitable for medium and large constructions, cold-formed ones are commonly used in small and medium constructions to compose roof structures, composite slabs and beams, mezzanines, popular houses, small warehouses and up-to-four-storey buildings. In addition, many cross sections are available for design, as C, Z, L and hat, doubled or not, stiffened or not (Silva et al., 2014). One important application of cold formed steel profiles in structural engineering, as presented previously, is in composite slabs. It gets incorporated to concrete after curing, allowing the composite behavior, and works as reinforcement, usually sparing additional ones. Besides, it's necessary to verify the structural safety before concrete curing, in which the steel formwork acts as a single steel beam and must resist to all ultimate limit states that can occur in construction st...

ResumoIn this work, a comparative study of different simplified methods and nonlinear finite element (FE) models used for calculating short-term deflections (vertical displacements of the longitudinal axis) in continuous reinforced concrete (RC) beams, under service loads, is performed. The simplified methods employed are the one proposed by Branson and the bilinear method recommended by the European Code CEB -Design Manual on Cracking and Deformations. Two finite element models are utilized: the first one with frame elements in which material nonlinearities are considered along the element and its cross section divided into layers, by using of constitutive relationships for steel and concrete, while the second one utilizes beam elements, with physical nonlinearity considered by means of moment-curvature diagrams, obtained from Branson equation. Several examples of continuous RC beams under service loads are analysed and the results obtained by the different models are compared taking as reference the nonlinear frame element model. A few conclusions and recommendations regarding the use of the different methods are drawn at the end of the work.Keywords: deflections, beams, reinforced concrete, nonlinear analysis.Neste trabalho é realizado um estudo comparativo dos resultados de flecha (deslocamento vertical do eixo longitudinal) imediata de vigas contínuas de concreto armado sob cargas de serviço, obtidos por diferentes métodos simplificados e por modelos não lineares de elementos finitos (EF). Os métodos simplificados abordados são o proposto por Branson e o método Bilinear recomendado pelo CEB -Manual de projeto sobre Fissuração e Deformações. São utilizados dois modelos de EF: o primeiro com EF de pórtico plano, sendo a não linearidade dos materiais considerada ao longo do elemento e da seção discretizada em camadas, a partir de relações constitutivas do aço e do concreto, enquanto que o segundo utiliza EF de viga, sendo a não linearidade física considerada por meio de diagramas momento-curvatura, obtidos a partir da fórmula de Branson. Os resultados dos diferentes modelos são comparados entre si para diversas vigas de projeto, adotando como referência os resultados do modelo não linear de elementos de pórtico plano. A partir da análise dos resultados, extraem-se algumas conclusões e recomendações quanto ao uso dos métodos simplificados e modelos de EF estudados.Palavras-chave: flecha, vigas, concreto armado, análise não linear.

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Resumo: Devido à nova realidade do ensino remoto, imposto pela pandemia do novo Corona vírus, os docentes vêm adaptando e buscando metodologias e ferramentas adequadas a esta modalidade de ensino. O objetivo deste texto é contribuir na adaptação e avaliação do material didático Kit Estrutural Mola no ensino remoto de estruturas. Amplamente utilizado no ensino presencial de estruturas, o Kit Mola permite a simulação de estruturas reais, auxiliando a análise e a compreensão de conceitos fundamentais sobre estruturas. Este material é empregado de forma adaptada no ensino remoto da disciplina de Análise Estrutural I, do curso de Engenharia Civil da Universidade Federal do Espírito Santo. São descritos os conteúdos produzidos e os exercícios propostos com esta ferramenta, tendo como principal objetivo a visualização pelos alunos dos conceitos estudados de forma teórica. De maneira a avaliar o impacto da utilização do Kit Mola no aprendizado, foi realizada uma pesquisa qualitativa com os discentes do semestre letivo corrente. Constatou-se que a utilização do Kit Mola no ensino remoto teve um impacto positivo no aprendizado. Ao final, lista-se algumas sugestões de aplicação deste material.