Earthquakes: innovative technologies for improving prevention and safety

Optical fibers, interferometers, accelerometers are just a few of the advanced anti-seismic technologies to reduce the risk from earthquakes in Italy. At ENEA a conference to take stock of the situation.

Making available increasingly reliable procedures of analysis and evaluation, reducing the costs of anti - seismic technologies, making them more available and guaranteeing a proper use of monitoring techniques. These are just a few of the ENEA’s proposals presented at the conference “Monitoring of sites and structures. Current status and future prospects”, held in Rome at the Agency’s Headquarters. “A wider application of seismic monitoring systems is crucial to prevent irreversible damage that would entail substantial renovation costs or even demolition”, points out Paolo Clemente, research manager at ENEA.

Interferometer at Ponte della Musica in Rome

Japan and the United States have the most advanced earthquake detection technology and California has long introduced a  levy on new constructions to finance this type of analysis.

In Italy the ENEA technologies are being used to monitor the new building of the Francesco Jovine  school in San Giuliano di Puglia (Molise region), Palazzo Marchesale, the historical city hall building and three structures of the Civil Protection Regional Center in Foligno (Umbria region), the operative headquarters and the guesthouse - both constructed using anti-seismic technologies - and an industrial warehouse.

Accelerometers have been placed on the structures, allowing to monitor the building in the event of an earthquake and evaluate its structural reliability over time. The results of the monitoring activities, transmitted to the proprietary government bodies- the San Giuliano Municipality and  the Umbria Region- will soon be available to the general public through an interactive platform.

“Dynamic monitoring is an effective diagnosis tool- Clemente goes on- allowing to verify the actual building performance in new constructions- to be compared with that envisaged in the planning stage- while allowing to estimate the state of the health and the possible damage of old constructions”.

Interferometer to monitor a landslide site in San Giuliano di Puglia

Seismic monitoring allows therefore to control a structure and intervene before damage becomes irreversible, a crucial activity especially for strategic infrastructures and sensitive buildings such as schools and hospitals.

The  interferometric radar system, ranked among the most effective technologies at the moment and previously employed to monitor the Aurelian Column in Rome, is a tool allowing to measure vibrations in structures such as towers and linear bridges and remotely monitoring landslide sites, without access to the site or structure.

All this at affordable costs. “Perfect for monitoring a bridge hard to access or a tall building- Clemente explains- the interferometric radar system can be placed at a distance of hundreds of meters because it sends electromagnetic waves: the variations of the reflected signal allow to understand how the structure is vibrating. At ENEA we’ve already tested its efficacy and other applications with “NHAZCA”, a spin-off of  La Sapienza University of Rome, are under way”.

The collaboration used as “case study” the Ponte della Musica in Rome, with the simultaneous use of the NHAZCA interferometric radar system –Natural HAZards Control and Assessment- and ENEA seismometers.  Another very efficient technology is optical fibers,  - also low cost- currently employed for monitoring several structures, including a partition of poles in San Giuliano di Puglia.

Monitoring of the Aurelian Column in Rome

They are sensors “glued”- during construction- to the metal armatures of the concrete poles, allowing to measure the deformation of the partition and obtain information on its state of health. It’s possible to insert in each single cable up to 20 sensors reflecting the light beam transmitted along the path; it’s possible to measure deformation from the characteristics of the reflected light.

During the conference the case of the West Valley College in California, hit by the Morgan Hill earthquake in 1984, was cited: the monitoring system showed that its roof was too flexible and that made it vulnerable to seismic events. The building was then modified and the following seismic codes were designed on the basis of the knowledge gained. The American case, but there are others, thought us that monitoring of structures is a precious tool for gaining more knowledge on their dynamic characteristics and that is crucial for updating technical codes, planning  new structures and improving  existing ones.

The conference was also an occasion to pay homage to engineer Dario Rinaldis and his commitment to research at ENEA. He was a precursor in the field of seismic monitoring in the mid-eighties and among his main activities was his contribution to creating a national accelerometric network for seismic monitoring, currently managed by the Civil Protection Department.

For more information please contact:

Paolo Clemente, ENEA Casaccia Research Center paolo.clemente@enea.it