Infill masonry: simple analytical methods for seismic design

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

Behavior of masonry infill panels in RC frames subjected to in plane and out of plane loads

The building envelope in Europe is usually made of masonry walls, with enclosure and infill functions. Masonry walls have a major economical importance and contribute significantly to the building performance. Even if infill walls have no load-bearing function, they contribute significantly to the seismic behavior of buildings. Therefore, their adequate structural performance is needed, avoiding the occurrence of severe in-plane damage, with very large economical losses, and the out-of-plane expulsion, which additionally represents a large risk for human life. Recent earthquake codes in Europe require the safety assessment of non-structural elements (parapets, veneer masonry walls, infill walls, etc.), when their collapse entails risks for people or for the main structure. The Eurocode standards, entering the mandatory stage now, incorporate new requirements to be fulfilled by buildings or their parts. Such is the case of masonry infilled RC frames whose panels, according to Eurocode 8, are explicitly required to withstand the out-of-plane movement induced by earthquakes. Appropriate measures should be taken to avoid brittle failure and premature disintegration of the infill walls, as well as the partial or total out-of-plane collapse of slender masonry panels. This paper presents the experimental work and results achieved by applying cyclic out-ofplane loads to damaged masonry infilled RC frames. The masonry panels were previously damaged by applying an in-plane cyclic load after which the cyclic out-of- plane loads were applied. The frames and panels tested follow the traditional Portuguese RC structure construction system to which different types of reinforcement have been introduced in the panels

Geodynamic evolution of the São Fidelis - Santo António de Pádua sector, central Ribeira Fold Belt, SE Brazil

Análise estrutural e resultados petrológicos recentes em granulitos da zona central da Faixa Ribeira indicam que a fase de deformaçãoD1 (cavalgamentos de alta temperatura: 245-260º, 55-70º NW) foi simultânea com o pico metamórfico, atingido aos 565-575 Ma, após os episódios colisionais com imbricação de nappes há 630-610 Ma (D0). Os marcadores cinemáticos de D0 e D1 foram abundantemente apagados pela fase de deformação D2. Esta apresentou uma componente cavalgante e, fundamentalmente, de cisalhamento direito (50-65º, 70-85º NW), associada a transpressão direita de longa duração, relacionada com uma prolongada taxa de arrefecimento do orógeno que durou até 480-520 Ma. O evento tectónico D3, frágil e em regime extensional (290-320º=, subvertical), associado a relaxamento térmico e à instalação de granitos tardios na área, foi seguido pelo colapso orogénico, aumentando drasticamente as taxas de arrefecimento há - 470 Ma. Os resultados sugerem que terá ocorrido um período de > 35 Ma de encurtamento ortogonal entre o Cratão de São Francisco e o Cratão do Congo Ocidental, até há 565 Ma, com o desenvolvimento da estrutura em flor D1. Posteriormente, quando as rochas deixaram de suportar encurtamento, o egime transpressivo direito D2 tornou-se predominante, tornando a estrutura em flor assimétrica. O posicionamento específico no interior da estrutura em flor e a existência de uma forte partição da deformação induziu cinemática antitética esquerda em alguns locais, dentro da estrutura predominantemente direita, bem como exumação diferencial: os granulitos na zona central da estrutura foram rapidamente exumados, enquanto nos ramos lateriais a exumação procedeu-se de uma forma mais lenta, resultando em taxas de arrefecimento muito baixas que duraram quase 100 Ma

Thermochronological evidence for long-term elevated geothermal gradients in Ribeira Belt, SE Brazil

Publicado em: Geochemica et Cosmochimica Acta, Vol. 71, issue 15, Suppl. 1, A7