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No / This paper presents a numerical investigation into the behaviour of headed shear stud in composite beams with profiled metal decking. A three-dimensional finite element model was developed using general purpose finite element program ABAQUS to study the behaviour of through-deck welded shear stud in the composite slabs with trapezoidal deck ribs oriented perpendicular to the beam. Both static and dynamic procedures were investigated using Drucker Prager model and Concrete Damaged Plasticity model respectively. In the dynamic procedure using ABAQUS/Explicit, the push test specimens were loaded slowly to eliminate significant inertia effects to obtain a static solution. The capacity of shear connector, load-slip behaviour and failure modes were predicted and validated against experimental results. The delamination of the profiled decking from concrete slab was captured in the numerical analysis which was observed in the experiments. ABAQUS/Explicit was found to be particularly suitable for modelling post-failure behaviour and the contact interaction between profiled decking and concrete slabs. It is concluded that this model represents the true behaviour of the headed shear stud in composite beams with profiled decking in terms of the shear connection capacity, load-slip behaviour and failure modes.

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no / Composite beams formed by connecting the concrete slabs to the supporting steel beams have been in use for many years. Much of the research into this form of construction has concentrated on the more traditional reinforced concrete and metal deck construction. In composite beam design, the strength of the shear connector is of great importance since longitudinal shear forces must be transferred across the steel-concrete interface by the mechanical action of shear connectors. The shear strength and stiffness of the connection is not only dependent on the strength of the connector itself, but also on the resistance of the concrete slab to longitudinal cracking caused by the high concentration of shear force at each connector. Present knowledge of this behaviour is limited to shear connectors in solid reinforced concrete slabs and concrete slabs with profiled sheeting, little information is given for the shear connector capacity on composite steel beam with precast hollow core slabs. A new horizontal push off test is proposed to determine the shear capacity of the connector on the composite beams with precast concrete hollow cored floor slabs. The results showed the new test is compatible with all type of floor and shear connectors, and can replace the existing vertical push off tests.

Yes / This paper outlines an experiment on a 12 m long composite beam subjected to uniformly distributed loading. Although composite beams are widely used, current Eurocode design guidelines for these types of members can be over-conservative, particularly in relation to the required degree of shear connection. The tested beam comprised a concrete slab supported by profiled metal decking, connected to an asymmetric fabricated steel I-beam using welded shear studs. The specimen was assembled using unpropped construction methods and had a degree of shear connection equal to 33%, significantly lower than the minimum required amount specified in Eurocode 4. A uniformly distributed load was applied to the specimen, which was increased until the failure occurred characterized by yielding of the steel beam. The maximum bending moment of the composite beam obtained from the test was close to the plastic bending resistance according to the Eurocode 4. No concrete crushing or shear stud failure was observed and the end slips exceeded 6 mm, the limit for ductile behaviour in Eurocode 4. The test demonstrated the merits of unpropped construction, which are currently not fully exploited in Eurocode 4. The comparison and analysis suggest that the design limits governing the minimum degree of shear connection might be revised. / RFCS

A utilização do elemento estrutural viga mista aço-concreto, que consiste da associação de vigas de aço (perfil do tipo I) com lajes de concreto (maciça ou com forma de aço incorporada), têm sido considerável nas obras de engenharia civil, tanto no contexto mundial como no Brasil. Parte da eficiência desse elemento estrutural está diretamente relacionada ao trabalho em conjunto de ambos os materiais, ou seja, do tipo de interação entre aço e concreto. Para um comportamento estrutural adequado das vigas mistas, essa interação é garantida por meio de elementos metálicos denominados conectores de cisalhamento, cujas principais funções consistem em transferir forças de cisalhamento longitudinais do concreto para o aço na interface entre laje e viga, bem como impedir a separação vertical entre laje de concreto e perfil metálico, movimento conhecido como uplift. Nesse sentido, o presente trabalho tem como objetivo principal uma pesquisa com base em referências bibliográficas sobre o assunto vigas mistas, bem como é proposta a elaboração de um modelo numérico tridimensional para viga mista, objetivando simular satisfatoriamente seu comportamento estrutural, em temperatura ambiente e em situação de incêndio, cujos resultados serão comparados com valores, obtidos numérica e experimentalmente, extraídos de trabalhos apresentados por outros pesquisadores. Para a modelagem numérica, utilizou-se o código de cálculo ABAQUS 6.3-1, elaborado com base nos métodos dos elementos finitos (MEF) / Composite steel-concrete beam have been commonly considered in steel-framed building used in civil engineering, not only in Brazil but also in the worldwide context. The efficiency of this structural element is directly related with the type of interaction between steel beam and concrete slab, which is assured using metallic elements called shear connectors, with the objective to transfer longitudinal shear forces from concrete slab to steel beam, in the interface, and avoid the vertical separation between concrete slab and steel beam (uplift). In this sense, the aim of the present work is to carry out a bibliographical review about composite steel-concrete beam, as well as propose a three dimensional non-linear procedure for modeling only full shear connection in composite beam. The three-dimensional numerical models constructed must be capable of predicting de response of composite beam, in ambient temperature an also in elevated temperatures (fire conditions). The computer program ABAQUS 6.3-1, based on finite element method, was used to analyze the numerical modeling. The accuracy of the three-dimensional numerical models are demonstrated by analyses of the results obtained with the models which are compared with the experimental results, obtained and presented by others researches

A utilização do elemento estrutural viga mista aço-concreto, que consiste da associação de vigas de aço (perfil do tipo I) com lajes de concreto (maciça ou com forma de aço incorporada), têm sido considerável nas obras de engenharia civil, tanto no contexto mundial como no Brasil. Parte da eficiência desse elemento estrutural está diretamente relacionada ao trabalho em conjunto de ambos os materiais, ou seja, do tipo de interação entre aço e concreto. Para um comportamento estrutural adequado das vigas mistas, essa interação é garantida por meio de elementos metálicos denominados conectores de cisalhamento, cujas principais funções consistem em transferir forças de cisalhamento longitudinais do concreto para o aço na interface entre laje e viga, bem como impedir a separação vertical entre laje de concreto e perfil metálico, movimento conhecido como uplift. Nesse sentido, o presente trabalho tem como objetivo principal uma pesquisa com base em referências bibliográficas sobre o assunto vigas mistas, bem como é proposta a elaboração de um modelo numérico tridimensional para viga mista, objetivando simular satisfatoriamente seu comportamento estrutural, em temperatura ambiente e em situação de incêndio, cujos resultados serão comparados com valores, obtidos numérica e experimentalmente, extraídos de trabalhos apresentados por outros pesquisadores. Para a modelagem numérica, utilizou-se o código de cálculo ABAQUS 6.3-1, elaborado com base nos métodos dos elementos finitos (MEF) / Composite steel-concrete beam have been commonly considered in steel-framed building used in civil engineering, not only in Brazil but also in the worldwide context. The efficiency of this structural element is directly related with the type of interaction between steel beam and concrete slab, which is assured using metallic elements called shear connectors, with the objective to transfer longitudinal shear forces from concrete slab to steel beam, in the interface, and avoid the vertical separation between concrete slab and steel beam (uplift). In this sense, the aim of the present work is to carry out a bibliographical review about composite steel-concrete beam, as well as propose a three dimensional non-linear procedure for modeling only full shear connection in composite beam. The three-dimensional numerical models constructed must be capable of predicting de response of composite beam, in ambient temperature an also in elevated temperatures (fire conditions). The computer program ABAQUS 6.3-1, based on finite element method, was used to analyze the numerical modeling. The accuracy of the three-dimensional numerical models are demonstrated by analyses of the results obtained with the models which are compared with the experimental results, obtained and presented by others researches

Foram realizados estudos das ações e suas combinações, que possam ocorrer nas pontes; também foram apresentados as principais características das pontes em vigas mistas e os tabuleiros utilizados, os conectores de cisalhamento que são utilizados na ligação aço/concreto e os efeitos da retração e fluência das vigas mistas. No estudo desses efeitos realizou-se uma análise elástica; a seção transversal foi considerada idealizada e as tensões atuantes na seção mista foram obtidas através do método das tensões admissíveis. Este procedimento foi baseado por Djuric (1963) posteriormente por Mason (1976), considerando interação completa entre aço/concreto e o carregamento sendo aplicado no tempo t=0 e no tempo t='infinito'. Verificou-se ao longo do tempo um aumento do deslocamento e uma redistribuição de tensões na seção mista devido os efeitos da retração e fluência / It was achieved studies of the actions and it’s combinations that can happen at the bridges also it was presented the main characteristics of the bridges in composite beams and the slab applied the shear connectors that are utilized at the joining steel/concrete and the effects of the shrinkage and creep of the composite beams. In the study these effects come about an analysis elastic the cross-section was considered idealized and the stresses that actuate at the composite section were obtained through the method admissible stresses. This procedure was based by Djuric (1963) later by Mason (1976) considering full interaction between steel/concrete and the load being applied at the time t=0 and at the time t='infinite'. It was verified along the time a rise of the deflection and a redistribution of the stresses at the composite section due to the effects of the shrinkage and creep

As vigas mistas de aço-concreto vêm ganhando espaço no mundo e no Brasil. Sua grande vantagem é o aproveitamento das melhores propriedades que cada material apresenta. O aço possui excelente resposta para esforços tanto de tração como os de compressão e o concreto para esforços de compressão. As vigas mistas envolvem basicamente o perfil de aço, a laje de concreto, os conectores e as armaduras. Na interface destes materiais ocorrem fenômenos que merecem destaque, como grau de interação, cisalhamento na superfície de contato e separação vertical. Os procedimentos normalmente empregados em projetos de estruturas convencionais de concreto armado e de aço fornecem muitas respostas para questões semelhantes nas estruturas mistas, porém, no geral, não abordam a questão mais relevante que é a ligação entre o aço e o concreto. Na vizinhança dos conectores de cisalhamento, a laje da viga mista de aço e concreto está sujeita a uma combinação de cisalhamento longitudinal e momento fletor transversal, por isso a interface é a região que necessita de uma análise cuidadosa. Esses aspectos são os objetos principais da pesquisa. Adicionalmente são discutidos os procedimentos de projetos adotados pelas normas brasileira (NBR 8800-86), americana (AISC) e européia (EUROCODE 4): nas regiões de ligações entre os materiais por meio de conectores em perfis de aço sob lajes de concreto, no controle da fissuração em seções solicitadas por momentos negativos e nas armaduras transversais de costura. / The use of composite steel-concrete beams is increasing in Brazil and in the world, because this is to take advantage of the best properties of each material. Steel has an excellent response to compression and tension and concrete has to compression. Composite beams include basically the steel beam, concrete slab, connectors and reinforcement. Some phenomena in the interface of these materials must be considered, like the degree of interaction, shear in contact surface and uplift. The procedures normally taken in design of conventional structures of reinforced concrete and steel structures supply many answers to similar questions in composite structures, but, in general, they do not approach the most relevant question which is the bond between steel and concrete. The slab of composite steel-concrete beam is affected by a combination of longitudinal shear and transverse flexure, in the neighborhood of the shear connector. The analysis of the behavior of the slab and the reinforcement are main aspect of the work. In addition, some design procedures adopted by Brazilian Standard (NBR 8800-86), American Standard (AISC-2005) and European standard (EUROCODE 4) are discussed, in especial the related to connects, the crack control in sections with hogging moment and in transverse reinforcement.