New Materials for the Rehabilitation of Cultural Heritage - Czech ...

New Materials for the Rehabilitation of Cultural Heritage 23
(a) (b)
Figure 17 –Application of CAM system: (a,b) two examples of strengthened masonry.
The distance between holes is normally equal to 1000-1500 mm, depending on masonry
characteristics. A specific tool is used for pretensioning the steel strips.
Some diagonal compressive tests allowed evidencing the effectiveness of this system [6]. The
summary of the tests shows an appreciable increase in shear resistance and a considerable
increase in ductility. In fact, the resistance increase was 15% in one case and 50% in the other
case. The maximum displacement of strengthened specimens was almost one order of
magnitude greater than that of unreinforced specimens (Fig. 18).
For applications it is necessary to carry out some diagonal compression in situ test to assess
the mechanical characteristics to be assumed in the structural analysis. In the design of the
reinforcement it is possible to use the relationships available for reinforced masonries.
The technique has the same shortcomings of the reinforced coating technique, so that it
cannot be used in buildings with frescos or decorations on the walls.
Displacement (mm) Displacement (mm)
(a) (b)
Figure 18 –Results of the diagonal compression tests: (a) unstrengthened specimen, (b)
specimen strengthened with CAM system.
4.2.4 “Reticolatus”
Also the “reticolatus” technique, which consists in the use of FRP wires or stainless steel
strands that are organized as a net, is effective to strengthen masonry buildings. The wires or