ELIZABETH VINTZILEOU National Technical University of Athens

The attainment of compressive strength of masonry is followed by a practically vertical falling branch. This undesirable behaviour may lead to disintegration of plain masonry subjected to compression or to local disintegration of the compressive zone in masonry elements subjected to bending. The aim of this paper is to explore the possibility of improving the ductility characteristics of masonry by introducing reinforcement in the horizontal joints. Ten masonry prisms made of vertically perforated bricks laid in lime.cement mortar were tested in compression. Four masonry prisms were plain and six prisms were horizontally reinforced using structural wire mesh. Small percentages of horizontal steel (0.0526% or 0.0876%) were used. The specimens were subjected to strain controlled tests, in order to obtain the falling branch of the stress/strain diagram as well. The experimental results showed that the small amount of horizontal confining reinforcement did not lead to an increase of the compressive strength of masonry. On the contrary, an increase of the strain corresponding to maximum stress was recorded (from 0.00158 to 0.00180). In addition, the slope of the falling branch was smaller in the case of horizontally reinforced prisms. Thus, the ductility factor of masonry in compression has increased by approximately 50% (from 1.36 to 1.96). Taking into account that the bricks selected for testing were very brittle and that the percentage of horizontal steel used was small, it is believed that the results obtained within the programme show that the confinement of masonry using bed joint reinforcement is feasible at a low cost. Such a confinement may prevent (local or general) disintegration of masonry, also making any post damage intervention easier.