@phdthesis {1578,
	title = {Avalia{\c c}{\~a}o do desempenho das envolventes dos edif{\'\i}cios face {\`a} ac{\c c}{\~a}o dos sismos},
	year = {2013},
	month = {2013-01-01 00:00:00},
	type = {phd},
	abstract = {
The building envelope in Europe is usually made of masonry walls, with enclosure and infill
functions. Masonry walls have a major economic 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
economic losses, and the out-of-plane expulsion, which additionally represents a large hazard
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 danger 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.
The analysis of buildings constructed in the last 20 years, designed following modern standards,
may lead to worrying conclusions. Images of out-of-plane expulsions and severe in-plane
damage of infill walls in recent seismic activities around the world reminded engineers of the
consequences of bad practice, wrong solutions or inadequate design.
This work presents the experimental work and results achieved by applying cyclic out-of-plane
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.
In order to achieve the proposed goals a residential building characterization was carried out in
Portugal and it has focused in the buildings envelope and its structure so that representative
samples could be studied. As a result, three models were built: a model which represents the
Portuguese traditional buildings since the nineteen-eighties which has a reinforced concrete
structurale design according to present codes and cavity walls plastered as envelope solution;
two models designed according to European legislation which aim to be a future solution where
both are reinforced concrete frame with infilled masonry with either bed joint reinforcement or
masonry infilled panels with external reinforcement.
An experimental campaign was carried out in order to determine: the masonry properties; outplane
panel behavior with previous in-plane damage; and building behavior subjected to
dynamic tests performed in the shaking table. Parametric tests were also conducted, to
establish analytical models able to reproduce in-plane and out-plane behavior leading to an
estimated load bearing capacity for each model.
It was concluded that panels subjected to horizontal in-plane loads got a damage condition
correlated to the load bearing panel capacity. It was noticed that the interfaces
masonry/concrete behavior leads the panel to the nonlinear stage and thereafter masonry
cracks in diagonal patterns occur and corners got crushed, until column and beam connection
finally fails. For the out-plane tests, traditional walls had the weaker performance and both
reinforced solutions had higher loadbearing capacity.
From the dynamic experimental campaign performed in the shaking table it was concluded that
the traditional walls had clearly a weaker resistance than the reinforced models designed
according to the European coded.
These studies also made possible the development of a design method, supported by the
presented results and in-plane and out-plane behavior of reinforced concrete frames with
masonry infill state of the art, can be used to verify the masonry infill stability.
},
	keywords = {Building envelope, Reinforcement., Seismic behavior},
	url = {http://sieeum.eng.uminho.pt/publicacoes/pub.aspx?pubid=14847},
	author = {Pereira, M. F. P. and Aguiar, J. B. and Louren{\c c}o, P. B. and Cam{\~o}es, A.}
}