Modelação por elementos finitos do comportamento de ligações aparafusadas sem e com resina injetada
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2015-04-20
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A presente dissertação de mestrado tem como principal tema de estudo a análise do comportamento de ligações metálicas aparafusadas sem e com resina injetada submetidas a carregamentos monotónicos, através do uso de modelos numéricos.
Sabendo que as ligações aparafusadas permitem acelerar os processos construtivos e, tendo em conta que, num mundo cada vez mais competitivo e globalizado em que os custos são um fator decisivo na conceção de um projeto, o uso de métodos computacionais na análise destas ligações vai-se tornando cada vez mais imperioso, sobretudo quando se tratam de novas soluções ainda pouco referidas em termos de códigos de projeto.
As ligações aparafusadas têm vindo, ao longo dos anos, a sofrer alterações resultantes das investigações que os vários intervenientes foram realizando. Os rebites foram substituídos pelos parafusos que, por sua vez, foram evoluindo até se começar a aplicar pré-esforço. Posteriormente, novas técnicas permitiram a injeção de resina como alternativa ao uso de parafusos ajustados. Desta forma, os engenheiros estruturais preocupam-se cada vez mais em estudar estas ligações, com o objetivo de aperfeiçoar estudos já realizados e até possibilitar a criação de novas técnicas.
Dito isto, para a elaboração desta dissertação procurou-se desenvolver metodologias de análise por elementos finitos de ligações aparafusadas sem e com resina injetada. Foram modeladas duas ligações aparafusadas, uma de corte duplo e uma ligação viga-pilar. Para cada uma destas ligações foram modeladas ligações aparafusadas pré-esforçadas com parafusos normais, parafusos ajustados e parafusos com resina injetada. Foram construídos modelos de elementos finitos capazes de simular o comportamento não linear das ligações permitindo a comparação de desempenho de cada solução construtiva.
No presente estudo verificou-se que as ligações aparafusadas com resina injetada produzem um comportamento estrutural próximo dos parafusos ajustados, eliminando os patamares de deslizamento típicos nas curvas de resistência das ligações com parafusos normais com folga.
The main goal of the present master dissertation is to study the behavior of bolted steel connections with and without injected resin submitted to monotonic loads, through the use of numerical models. Having in mind that bolted connections allow speed up constructive processes and, knowing that in a world each time more competitive and globalized in which the costs are a decisive factor in the development of a project, the use of computational tools in the analysis of these connections becomes determinant, mainly for new solutions or solutions less explored in terms of design codes. The bolted connections have been, throughout the years, suffering transformations resulting from research activities performed by many authors. The rivets have been replaced by bolts that have evolved, the main achievement being the prestrussed bolts. Following this, new techniques suggested the injection of resin as an alternative to the use of fitted bolts. Structural engineers are each time more concerned with the study of these connections, aiming a better understanding of their performance and the development of new techniques. In this dissertation, methodologies based on finite element analyses were proposed for bolted connections, with and without injected resin. Two types of bolted joints were investigated, double shear splice and beam-to-column connection. For each joint configuration, standard bolts, fitted bolts and resin injected bolts were simulated. The non linear behavior of these connections was investigated and their performances were compared. In this study, it was found that the injected resin in bolted connections causes a structural behavior of the fitted bolts, eliminating the levels of sliding in the resistance curves that are typical in the standard bolted connections with clearance.
The main goal of the present master dissertation is to study the behavior of bolted steel connections with and without injected resin submitted to monotonic loads, through the use of numerical models. Having in mind that bolted connections allow speed up constructive processes and, knowing that in a world each time more competitive and globalized in which the costs are a decisive factor in the development of a project, the use of computational tools in the analysis of these connections becomes determinant, mainly for new solutions or solutions less explored in terms of design codes. The bolted connections have been, throughout the years, suffering transformations resulting from research activities performed by many authors. The rivets have been replaced by bolts that have evolved, the main achievement being the prestrussed bolts. Following this, new techniques suggested the injection of resin as an alternative to the use of fitted bolts. Structural engineers are each time more concerned with the study of these connections, aiming a better understanding of their performance and the development of new techniques. In this dissertation, methodologies based on finite element analyses were proposed for bolted connections, with and without injected resin. Two types of bolted joints were investigated, double shear splice and beam-to-column connection. For each joint configuration, standard bolts, fitted bolts and resin injected bolts were simulated. The non linear behavior of these connections was investigated and their performances were compared. In this study, it was found that the injected resin in bolted connections causes a structural behavior of the fitted bolts, eliminating the levels of sliding in the resistance curves that are typical in the standard bolted connections with clearance.
Descrição
Dissertação de Mestrado em Engenharia Civil
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Comportamento dos materiais , Ligações metálicas