67 research outputs found
Strengthening of three-leaf stone masonry walls: an experimental research
The paper summarizes the results of an experimental research carried out on three-leaf masonry walls
of typical granite stone constructions from the North of Portugal. The research aimed at studying the behaviour
under compression of this wall typology, as well as the improvements introduced by common strengthening
techniques applied for the structural rehabilitation of masonry heritage buildings. Ten masonry specimens were
tested, plain or strengthened by transversal tying of the external leaves, with GFRP bars, or/and by injection of
the inner leaf, with a lime-based grout. The results obtained showed that these strengthening techniques were
successful in increasing the compressive strength of the walls and in improving their behaviour under
compressive loads.The authors would like to thank the technical staff of the Structural Laboratory of University of Minho for the help provided. Acknowledgements are also due to the companies Fradical, Mapei and Augusto de Oliveira Ferreira for providing raw materials and workmanship. Finally, the funding provided by the Portuguese Science and Technology Foundation, through the POCI/ECM/58987/2004 project, is gratefully acknowledged
Recommended from our members
Flexural behaviour of reinforced concrete jacketed columns under reversed cyclic loading
The objective of the present study is the development of an analytical model for predicting the response under reversed cyclic loading of structural members with ‘old-type’ detailing, strengthened with reinforced concrete (RC) jacketing. The analytical model introduces one additional degree of freedom between the existing member (core of the retrofitted member) and its outer RC shell, thus allowing slip to take place at the interface between the existing member and the jacket. Shear resistance mechanisms, such as aggregate interlock, friction, and dowel action, are mobilized to resist slip. Existing constitutive models are further improved to describe the mechanisms that resist sliding under cyclic shear reversals and implemented for the first time in an analytical model for deriving the response of RC jacketed members. A calculation algorithm is developed to estimate the flexural response under cyclic loading taking into account slip at the interfaces. The sensitivity of the proposed analytical model to the shear transfer mechanisms degradation rules, as well as to the crack spacing estimation, was evaluated. The validity of the proposed analytical model is assessed against experimental results
Seismic behaviour of traditional timber frame walls: experimental results on unreinforced walls
Timber frame buildings are well known as an efficient seismic resistant structure
and they are used worldwide. Moreover, they have been specifically adopted in codes and
regulations during the XVIII and XIX centuries in the Mediterranean area. These structures
generally consist of exterior masonry walls with timber elements embedded which tie the
walls together and internal walls which have a timber frame with masonry infill and act as
shearwalls. In order to preserve these structureswhich characterizemany cities in theworld it
is important to better understand their behaviour under seismic actions. Furthermore, historic
technologies could be used even in modern constructions to build seismic resistant buildings
using more natural materials with lesser costs. Generally, different types of infill could be
applied to timber frame walls depending on the country, among which brick masonry, rubble
masonry, hay and mud. The focus of this paper is to study the seismic behaviour of the walls
considering different types of infill, specifically: masonry infill, lath and plaster and timber
frame with no infill. Static cyclic tests have been performed on unreinforced timber frame
walls in order to study their seismic capacity in terms of strength, stiffness, ductility and
energy dissipation. The tests showed how in the unreinforced condition, the infill is able to
guarantee a greater stiffness, ductility and ultimate capacity of the wall.The authors would like to acknowledge Eng. Filipe Ferreira and A.O.F. (Augusto Oliveira Ferreira &
C Lda.) for their expertise and collaboration in the construction of the wall specimens.
The first author would also like to acknowledge the Portuguese Science and Technology
Foundation (FCT) for its financial support through grant SFRH / BD / 61908 / 2009
- …