Wall Test Procedures

3.1 Wall specimens

As exposed above, the entire ten wall specimens were built with three leaves, two granite masonry external leaves and an inner leaf built with granite scrabblings and mortar, without any compaction, aiming at obtaining an amount of voids representative of this kind of walls, able to allow injection. The average thickness of each leaf was about 100 mm, which wasn't always possible, due to the variable size and shape of the stones used. This feature also influenced the number of courses, which ranged from six to eight courses. The global dimensions adopted for all wall specimens were 600 mm long, 300 mm thick and 1100 mm high, similar to dimensions found in previous works (Vintzileou et al. 1995, Toumbakari 2002, Valluzzi et al. 2004) and aiming at representing 1/2 scaled models of real walls. It is worth to mention that no stones connecting the external leaves were used, in order to both assure the worst conditions found in ancient buildings and provide leaf interfaces for all specimens as similar as possible.

3.2 Strengthening

The transversal tying technique was applied and tested in the second and third series of walls. After drilling two holes with a diameter of 20 mm, through the entire wall thickness, at one third and two thirds of specimen's height, GFRP bars with 10 mm diameter were placed and the holes were injected with the aforementioned grout.

The injection technique was applied only in the third series of walls. Due to the low wall thickness, injection was applied just in one side of the walls. For that, the subsequent procedure was followed (see Figure 2):

(a) drilling of slightly inclined holes with 14 mm diameter. Their distance varied between 100 mm and 200 mm, depending on the location of masonry joints;

(b) introduction of small plastic tubes with a diameter of 10 mm in the holes; (c) sealing of holes and major mortar joint absences, caused by the drilling process, with silicone to prevent grout leakage; (d) injection of water to verify which tubes were active and to wet the inner leaf; (e) sealing of the transversal sides with polyurethane foam to prevent grout leakage and

Figure 1. Injected inner leaf: (a) general view of a wall's inner leaf; (b) crack pattern of a sampled specimen after testing.

Table 2. Summary of results of the unstrengthened walls.

Wall

(N/mm2)

(mm/m)

(N/mm2)

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