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Avaliação do desempenho das envolventes dos edifícios face à acção dos sismos

Pereira, Manuel Fernando Paulo
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Tese de Doutorado
Publicado em 16/07/2013 POR
Relevância na Pesquisa
27.22%
Tese de doutoramento em Engenharia Civil; A envolvente dos edifícios em Portugal é constituída quase exclusivamente por paredes de alvenaria, que têm principalmente a função de vedação. Apesar de não terem função estrutural, as paredes ao interagirem com a estrutura, condicionam o comportamento sísmico dos edifícios, exigindo-se-lhe sob esta óptica, um desempenho adequado, evitando a ocorrência de danos severos nas paredes no seu plano, que conduzam a perdas económicas graves, e o colapso das paredes para fora do plano, que poderão colocar em perigo vidas humanas. Os actuais regulamentos estruturais europeus, no que concerne à segurança sísmica das estruturas exigem a verificação da segurança de elementos não estruturais quando o seu colapso acarreta riscos para pessoas ou para a estrutura principal. Os Eurocódigos estruturais quando entrarem na fase de implementação obrigatória irão impor novas exigências que deverão ser cumpridas pelos edifícios ou pelas suas partes. Tal é o caso das alvenarias de preenchimento, que deverão resistir ao movimento para fora do plano imposto pela acção dos sismos, devendo ser tomadas medidas adequadas para evitar a rotura prematura e desintegração das paredes de preenchimento...

Numerical modelling of masonry-infilled reinforced concrete frames : model calibration and parametric study

Akhoundi, Farhad; Lourenço, Paulo B.; Vasconcelos, Graça
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 ENG
Relevância na Pesquisa
46.93%
Generally two methods are proposed for analyzing the infilled frames; Micro modelling approach which finite element method is used to take into account local effects in detail and Macro modelling approach which is a very simplified method that takes into account the global behavior of the structure by replacing the infill with diagonal strut. In the present study a numerical analysis is carried out on a one bay one storey reinforced concrete frame with masonry infill under in-plane loading by using finite element modelling through the DIANA software. The numerical model was calibrated based on experimental results and then a parametric study was carried out, taking into account variation of material properties of infill and its height to length ratio. It is concluded that compressive strength and height to length ratio of the masonry infill has dominant role on the in-plane behavior of these types of masonry infilled frames. Increasing the compressive strength of the masonry enhances the lateral strength of the infilled frames while increasing the height to length ratio of the infill panel results in decrease of their lateral strength and initial stiffness.; Fundação para a Ciência e a Tecnologia (FCT)

Avaliação do efeito das paredes de enchimento no comportamento dinâmico de edifícios de betão armado; Evaluation of the effect of masonry infills walls in the dynamic behavior of reinforced concrete buildings

Domingues, Julien
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2013 POR
Relevância na Pesquisa
56.9%
Dissertação de mestrado integrado em Engenharia Civil (área de especialização em Perfil de Estruturas e Geotecnia); Toda a história humana encontra-se recheada de eventos sísmicos que fustigaram as populações e a suas cidades de forma mais ou menos grave, dependendo da intensidade do sismo e da preparação das estruturas para resistirem. Perderem-se nesta luta travada contra a natureza e a sua implacável redundância um número bastante significativo de vidas humanas e danos materiais. Portugal, ao longo dos tempos, já prestou o seu tributo a esta triste causa e poderá no futuro encontrar-se novamente perante um evento sísmico de grandes proporções. A grande preocupação perante esta eventualidade é claramente o facto de o património edificado não estar a altura deste evento. Dentro dos edifícios modernos a maior preocupação, desencadeada em grande parte por recentes sismos em países vizinhos com resultados catastróficos, é a vulnerabilidade das paredes em alvenaria, pelo facto de poderem ceder segundo vários tipos de mecanismos de colapso. O objetivo deste trabalho é contribuir para o conhecimento da engenharia civil sobre o funcionamento destes elementos em particular e a sua influência no comportamento global das estruturas. Para tal...

Infill masonry : simple analytical methods for seismic design

Pereira, Manuel Fernando Paulo; Pereira, M. F. Neto; Ferreira, J. E. Dias; Lourenço, Paulo B.
Fonte: International Masonry Society Publicador: International Masonry Society
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 ENG
Relevância na Pesquisa
66.94%
The latest earthquake codes in Europe require the safety assessment of no-structural elements (parapets, masonry wall’s veneer, infill walls, etc.), as their collapse entails risks for people or for the main structure stability. This work made possible th e development of a design method, supported by previous experimental researches by applying cyclic out-of-plane loads to damaged masonry infill in RC frames. Panels tested reproduce Portuguese traditional RC structure construction system and two reinforced solutions were created as innovative solutions. The experimental campaign was carried out in order to determine: masonry properties; out-of-plane panel behaviour with previous in-plane damage; building behaviour subjected to dynamic tests performed in shaking table. Using finite element method to reproduce experimental tests and to broaden the range of samples it was possible to figure out equations according to parametric analysis which was able to reproduce in-plane and out-plane behaviour leading to an estimated load bearing capacity of each model and to determine frame strength and its stiffness. Those equations permit to design or verify the masonry infill panels in RC frames subjected to seismic loads.

Seismic assessment of rc structures with infill masonry panels in Nepal: sensitivity analysis

Chaulagain, Hemchandra; Rodrigues, Hugo; Spacone, Enrico; Varum, Humberto
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
67%
Reinforced concrete (RC) buildings in Nepal are constructed as RC frames with masonry infill panels. These structures exhibit a highly non-linear inelastic behaviour resulting from the interaction between the masonry infill panels and the surrounding frames. In this context, the paper presents an extensive case study of existing RC-framed buildings in a high seismic risk area in Nepal. A sensitivity analysis of the structures with masonry infill is performed. For this, the influence of different material properties is studied, namely diagonal compressive stress, modulus of elasticity and tensile stress of masonry infill panels. Result shows the influence on the structural behaviour particularly by variation of the diagonal compressive strength of infill masonry panels.

In-plane cyclic response of reinforced concrete frames with unreinforced masonry infills

Haider, Sarah
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
36.8%
The in-plane cyclic response of reinforced concrete frames with unreinforced masonry infill was studied. Four full-scale reinforced concrete frame assemblies with masonry infills were designed and tested under reversed cyclic loading. The effect of panel aspect ratio and the stiffness of the infill relative to the frame were studied in terms of stiffness, strength, energy dissipation and failure mode. Based on the test results, an equivalent diagonal compression strut model was developed to represent the behavior of masonry infill bounded by a reinforced concrete frame and a simplified method for the linear-elastic analysis of R/C frames with masonry infills proposed. Using the experimental load-deformation plots, the hysteretic parameters relating to stiffness degradation, strength deterioration and pinching of the hysteretic loops were identified. These may be used to define the behavior of confined infills for the non-linear analysis of the infilled frames.

Infill panel system for seismic strengthening of flat-plate buildings

Humay, Francis Kam
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
46.75%
Many existing flat-plate buildings are seismically deficient and pose a threat to life safety if subjected to ground motions of even low to moderate intensity. Failure in such structures is typically the result of punching failure at the slab-column connection. Because of this, performance-based retrofit procedures are needed to upgrade these non-ductile buildings. This investigation evaluated the use of lightweight pumice stone concrete (LWPSC) infill panels as a retrofit alternative for flat-plate buildings. Six four-tenth-scale slab-column subassemblies were designed and detailed based on ACI 318-63 and current performance-based testing requirements. Except for one bare frame specimen, all the subassemblies were retrofitted with prefabricated LWPSC infill panels and subjected to quasi-static loading conforming to FEMA 273. The geometry of the individual units was governed by weight limitations for handling and erection. Among the variables studied were connections between the slabs and the infill wall and the addition of uniformly distributed perforations (circular and rectangular openings). All of the retrofitted specimens had significant increases in both strength and stiffness over that of the bare frame. The behavior of the specimen with the infill panels not attached to the slabs was similar to that of a masonry wall without any connections to the frame. Although diagonal tension cracks formed within the recessed region...