An experimental program was conducted to investigate some aspects of in-plane behaviour of masonry infilled steel frames. Eight concrete masonry infilled steel frames, consisting of three fully grouted and five partially grouted infills, were tested under combined lateral and axial loading. All specimens were constructed using one-third scale concrete masonry units. The in-plane lateral load was gradually increased at the frame top beam level until the failure of the specimen while an axial load was applied to the top beam and held constant. The parameters of the study included axial load, extent of grouting, opening, and aspect ratio of the infill. The experimental results were used, along with other test results from the literature, to evaluate the efficacy of stiffness and strength predictions by some theoretical methods with a focus on Canadian and American design codes. Cracking pattern, stiffness, failure mode, crack strength, and ultimate strength of the specimens were monitored and reported. Presence of axial load was found to increase the ultimate strength of the infilled frame but had no marked effect on its stiffness. Two specimens exhibited “splitting failure” due to axial load. Partially grouted specimens developed extensive diagonal cracking prior to failure whereas fully grouted specimens showed little or no cracking prior to failure. An increase in grouting increased the ultimate strength of the frame system but reduced its ductility. Presence of opening reduced the ultimate strength of the infilled frame and increased its ductility but its effect on the stiffness of the frame system was not significant. A review of current Canadian and American design codes showed that the Canadian code significantly overestimates the stiffness of infilled frames whereas the American code provides improved predictions for stiffness of these frame systems. Both design codes underestimate the strength of masonry infilled steel frames but grossly overestimate the strength of masonry infilled RC frames. / Masonry infilled steel frames tested under combined axial and lateral loading. Behaviour as affected by axial load, grouting, aspect ratio and openings discussed. Correlation between axial load level and the infill lateral resistance examined. Efficacy of the Canadian and American masonry standards on infill design was examined.

A non-linear finite element program to simulate the behaviour of infilled frames and plane stress reinforced concrete members under the action of monotonic and cyclic loading has been developed. Steel is modelled as a strain hardening plastic material, and in the concrete model cracking, yielding and crushing are considered. The separation, sliding, and opening and closing of initial gaps at the interfaces between the frame and the infill panels are accounted for by adjusting the properties of interface elements. The non-linear equations of equilibrium are solved using an incremental-iterative technique performed under load or displacement control. The iterative techniques use the standard and modified Newton-Raphson method or the secant Newton method. An automatic load incrementation scheme, line searches, and restart facilities are included. The capabilities of the program have been examined and demonstrated by analysing five reinforced concrete panels, a deep beam, a shear wall, and eight infilled frames. The accuracy of the analytical results was assessed by comparing them with the experimental results and those obtained analytically by other workers and shown to be good. A study of the effects of some material and numerical parameters on the results of analyses of reinforced concrete deep beam has been carried out. Two techniques have been proposed and used to overcome numerical problems associated with local strain concentrations which occur with the displacement control, when path dependent incremental iterative procedures are used for inelastic materials. The displacement control provided with these modifications has been shown to be more efficient than the load control.

A non-linear finite element program to simulate the behaviour of infilled frames and plane stress reinforced concrete members under the action of monotonic and cyclic loading has been developed. Steel is modelled as a strain hardening plastic material, and in the concrete model cracking, yielding and crushing are considered. The separation, sliding, and opening and closing of initial gaps at the interfaces between the frame and the infill panels are accounted for by adjusting the properties of interface elements. The non-linear equations of equilibrium are solved using an incremental-iterative technique performed under load or displacement control. The iterative techniques use the standard and modified Newton-Raphson method or the secant Newton method. An automatic load incrementation scheme, line searches, and restart facilities are included. The capabilities of the program have been examined and demonstrated by analysing five reinforced concrete panels, a deep beam, a shear wall, and eight infilled frames. The accuracy of the analytical results was assessed by comparing them with the experimental results and those obtained analytically by other workers and shown to be good. A study of the effects of some material and numerical parameters on the results of analyses of reinforced concrete deep beam has been carried out. Two techniques have been proposed and used to overcome numerical problems associated with local strain concentrations which occur with the displacement control, when path dependent incremental iterative procedures are used for inelastic materials. The displacement control provided with these modifications has been shown to be more efficient than the load control. / Iraqi Government

Apresenta-se neste trabalho um estudo sobre o comportamento de estruturas de pórticos preenchidos por painéis de alvenaria submetidos a ações horizontais, considerando a contribuição de alvenaria na rigidez global da estrutura. Este estudo envolveu uma série de ensaios experimentais como protótipos de aço em escala real utilizando-se blocos celular autoclavados; a macromodelagem numérica pelo método dos elementos finitos; a aplicação do conceito da diagonal equivalente; e a realização de um estudo paramétrico, considerando-se pórticos com diferentes relações altura/comprimento, visando à obtenção de recomendações práticas para análise de pórticos preenchidos. Essas recomendações são apresentadas na forma de uma proposta para determinação da carga de ruptura em painéis de pórticos preenchidos com alvenaria, utilizando-se o modelo de bielas e tirantes. Os resultados obtidos com a aplicação desta proposta foram comparados com os dos modelos experimentais e teóricos disponíveis na literatura, comprovando-se a eficiência e praticidade em sua utilização. / This work presents a study of the behavior of masonry infilled frames structures, subjected to horizontal actions, regarding the contribution of the masonry to the structure global stiffening. The study consists of tests, in real size, in steel frames infilled with structural blocks of autoclaved aerated concrete; of the macromodeling using the finite element method; of the application of the concept of equivalnet diagonal struts and of the realization of a parametric study, regarding frames with different ratios height/length, aiming to get design recommendations for the analysis of infilled frames. These recommendations are presented as a proposal for determining the cracking load in panels of infilled frames with masonry. utilizing the strut-and-tie model. The results obtained with this proposal are compared with tests and predictions derived from approximate theoretical analyses, proving the efficiency and practicality in their utilization.

Apresenta-se neste trabalho um estudo sobre o comportamento de estruturas de pórticos preenchidos por painéis de alvenaria submetidos a ações horizontais, considerando a contribuição de alvenaria na rigidez global da estrutura. Este estudo envolveu uma série de ensaios experimentais como protótipos de aço em escala real utilizando-se blocos celular autoclavados; a macromodelagem numérica pelo método dos elementos finitos; a aplicação do conceito da diagonal equivalente; e a realização de um estudo paramétrico, considerando-se pórticos com diferentes relações altura/comprimento, visando à obtenção de recomendações práticas para análise de pórticos preenchidos. Essas recomendações são apresentadas na forma de uma proposta para determinação da carga de ruptura em painéis de pórticos preenchidos com alvenaria, utilizando-se o modelo de bielas e tirantes. Os resultados obtidos com a aplicação desta proposta foram comparados com os dos modelos experimentais e teóricos disponíveis na literatura, comprovando-se a eficiência e praticidade em sua utilização. / This work presents a study of the behavior of masonry infilled frames structures, subjected to horizontal actions, regarding the contribution of the masonry to the structure global stiffening. The study consists of tests, in real size, in steel frames infilled with structural blocks of autoclaved aerated concrete; of the macromodeling using the finite element method; of the application of the concept of equivalnet diagonal struts and of the realization of a parametric study, regarding frames with different ratios height/length, aiming to get design recommendations for the analysis of infilled frames. These recommendations are presented as a proposal for determining the cracking load in panels of infilled frames with masonry. utilizing the strut-and-tie model. The results obtained with this proposal are compared with tests and predictions derived from approximate theoretical analyses, proving the efficiency and practicality in their utilization.

Made available in DSpace on 2016-06-02T20:09:16Z (GMT). No. of bitstreams: 1 4457.pdf: 18463450 bytes, checksum: c0a25a178fa3c9a6561abc7109472ddc (MD5) Previous issue date: 2012-03-30 / Financiadora de Estudos e Projetos / This work proposes to develop a study about frame structure behaviour filled with masonry panel, for the purposes of building bracing. It aims to consider the hardening of this filling masonry in the frame which deals with the horizontal loadings analysis such as wind strength. The work starts with the historical development, depicting the fact that who started this study. Then, variables which influence the frame rigidity are shown, like: wedging, the kind of link between panel- frame, panel openings, codes and design specification. These topics describe theoretical and experimental studies that have already been carried out about the theme and the main approaches considered by the researchers. For the purpose of checking the structure stiffening increase some case study were held. The first one comprehends a simple frame, theoretical, with data and results obtained from specialized literature. The second one compares a steal frame tested on a laboratory, with a computer program modeled frame, using the same features as the real stuff. Then, the portics were analysed with different filled floors. For doing so, different available calculation methods were applied, which employ equivalent diagonal concept to consider the masonry filling contribution as a structural constituent. Bearing in mind to verify the stiffening increase when the filling masonry are considered, a real building was modeled, in this particular case Helena Building, it has 22 floors, built in São Paulo using reinforced concrete, either considering or not the filling masonry. As the research bottom line, this text allows an updating about the possibility of including the filling masonry in building projects, an evaluation of the stiffening increase that the masonry might cause, an analysis to verify the compressed diagonal model and finally it shows design criteria. / O presente trabalho propõe realizar um estudo da arte sobre o comportamento de estruturas aporticadas preenchidas com painéis de alvenaria, para fim de contraventamento de edificações. Visa considerar o enrijecimento dessa alvenaria de preenchimento no pórtico para análise de ações horizontais, como a força do vento. O trabalho inicia-se com o desenvolvimento histórico, descrevendo o fato que originou o estudo. Em seguida, apresenta variáveis que influenciam na rigidez do pórtico, como: encunhamento, tipo de ligação entre pórtico-painel, abertura em painéis, normas e considerações para projeto. Esses tópicos descrevem estudos teóricos e experimentais já realizadas sobre o tema e os enfoques mais relevantes considerados pelos pesquisadores. A fim de verificar o aumento de rigidez da estrutura foram realizados alguns estudos de caso. O primeiro trata-se de um pórtico simples, teórico, com dados e resultados obtidos na literatura especializada. A segunda análise compara-se um pórtico metálico ensaiado em laboratório, com um pórtico modelado em programa computacional, adotando as mesmas características do real. Em seguida, analisam-se teoricamente pórticos com diferentes pavimentos preenchidos. Para isso, adotaram diferentes métodos de cálculo disponíveis, que empregam o conceito de diagonal equivalente para considerar a contribuição do enchimento de alvenaria como elemento estrutural. Com propósito de comprovar o acréscimo de rigidez quando for considerada a alvenaria no preenchimento, foi modelado um edifício real, o edifício Helena, de 22 pavimentos, executado em concreto armado na cidade de São Paulo, considerando ou não a alvenaria de preenchimento. Como resultado da pesquisa, este texto permite uma atualização sobre a possibilidade de inclusão da alvenaria de enchimento no projeto de edificações, avaliar o aumento de rigidez que a alvenaria pode proporcionar, averiguar o modelo de diagonais comprimidas e, finalmente, indicar critérios para projeto.