Metal/basalt mesh-reinforced walls are 2.5 times stronger in earthquakes.
Devastating earthquakes often shake Italy: Nocera Umbra (1997), L’Aquila (2009), Emilia (2012). In 2016 an earthquake hit Norcia in the central Italy, destroying landmarks and taking a heavy death toll. Its magnitude ranged from 6.2 to 6.6 according to the Richter scale.
As part of the CoBRA project and scientific and technical cooperation between Italy and the United States, Roma Tre University, the National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) are conducting a series of tests. They focus on developing effective, inexpensive and easy-to-use building reinforcement methods.
For the experiment they built walls of the materials that are conventional for historical centers of the Central and Southern Apennines: stone and tuff. Each wall weighed two tons.
Unlike natural walls, the earthquake was man-made that is modeled using vibrating tables, able to move in six spatial dimensions (three directions of movement and three rotations).
These models were previously damaged on the vibrating tables like the walls of historic areas after earthquakes, then they were repaired and strengthened. For a further study they recorded the indicators against which the damage to the wall appeared. The masonry wall was reinforced by the FRCM system (fiber-reinforced cement matrix): bidirectional metal / basalt mesh.
Having been reinforced, the walls were experimentally studied again. New FRCM walls reinforced with basalt fiber and stainless steel proved to be damaged when exposed to two and a half times stronger shocks than before reinforcing.
New technologies turned out to be very promising for using composite materials in the construction industry, selecting appropriate technologies for seismic retrofitting and carrying out preventive measures to protect buildings and human lives, the researchers said.