The new European reference standard for structural design in seismic areas introduces the approach of integrated sustainability and risk mitigation with a concrete quantification of the probability of seismic damage

article by Marta Abbà and Lorenza Bisbano

Eurocode 8: the second generation of this “European reference standard for structural design in seismic areas” is being introduced. Code name, EC8-2G, objective: to evolve the way earthquakes are dealt with, not only by those called upon to design but also by those simply called upon to live in and use the infrastructure that stands on a certain territory, whether public or private.

Despite its bureaucratic tone and its “expert-only” nature, this new development contains two important steps forward with potentially high human impact. Much depends on how experts will be able to leverage this theoretical innovation to innovate in practice, but also on how aware we all become of its importance. Although the earth has been shaking frequently recently, we continue to turn a blind eye.

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Takeaway

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Environment and data: the pillars of Eurocode 8

Among the main new features contained in the new Eurocode 8, sustainability and risk quantification stand out. As for the former, the EU has decided to integrate more explicitly and firmly the need to pay greater attention to the environment. This is a turning point, given that until now the opposite has often been the case: the ‘seismic lever’ has been used to bypass recommendations to minimize emissions in the construction sector.

“The combination of sustainability and structural safety has only appeared in the last 5 or 6 years,” explains Rui Pinho, president of the Eucentre Foundation. “We are now beginning to see projects designed with optimization in mind: we want to waste less, use more materials with a low environmental footprint such as wood, use anti-seismic devices to limit damage, and employ construction techniques that allow for the recycling of structural components.”

The other new feature of Eurocode 8 is more closely linked to digitalization and the world of data. It concerns the need and ambition to translate the concept of seismic risk into numbers. This is a way of making it more concrete and real even to those who think it will always be someone else’s problem, never inherent to their own territory.

The challenge of zero risk

“In the previous version of the code, designers were not provided with the tools to explicitly estimate the probability that a structure could suffer severe damage if subjected to seismic action,” says Pinho. “In the second generation of Eurocode 8, they can do so, even together with the client, and this is a revolutionary change.”

According to Pinho, the standard could also trigger substantial reflection within society at a time in history marked by both seismic and geopolitical upheavals. “Today, people are increasingly asking to know the risk associated with a given phenomenon and want to manage it directly,” he adds. “For individual citizens, as for local public administrations, data that gives an idea of the extent of the risk is a powerful lever, whether for insurance companies, businesses, or institutions.”

According to Pinho, common awareness has changed and is still changing, and “information that was previously considered useless, or even inappropriate, is now the first thing that stakeholders, owners, and managers ask for: risk is becoming an increasingly important parameter in the entire process of structural design and management of structures and infrastructure.”

In this positive evolution towards a data-driven approach to earthquakes, Pinho highlights the difficulty experts have in conveying the concept that “zero risk does not actually exist, especially in a territory like ours.”

An earthquake-proof society from the ground up

In addition to ‘suffering’ from seismic shocks, Italy also has an innate vulnerability due to the large number of ancient buildings and structures. ‘Our historical and artistic heritage is highly vulnerable,’ observes Pinho, ‘and including the concept of seismic risk explicitly in the future will certainly prove beneficial.’

The evolution of technical and safety regulations for the building stock potentially affects the entire European landscape – some more than others – and all those who interact with it in some way: engineers, designers, administrators, companies, and future professionals. For the promises contained in the code to become reality, one of the most important challenges to overcome is that of training. For example, by promoting collaboration between disciplines such as architecture, structural engineering, and mechanical engineering, but also increasingly involving experts in environmental sustainability and information technology, “because buildings are becoming ever more intelligent, and the structural part is gradually becoming so too,” concludes Pinho.

New technologies, new knowledge

Technological innovation, impossible to ignore even in this sector, is manifesting itself in various forms. “To reduce seismic risk, new construction techniques, new materials, and new devices can be introduced. This standard regulates them and facilitates those who want to adopt them,” says Alberto Pavese, professor at the University of Pavia.  Among these solutions, he cites seismic isolation and damping systems, which aim to absorb the energy transmitted by earthquakes, preserving structural elements or limiting possible damage. Then there are digital twins and artificial intelligence tools, based on machine learning algorithms, which Pavese considers powerful aids in the design and management process throughout the entire life cycle of a structure. “They have advanced significantly and have become part of everyday life, increasing design management capabilities and the level of expertise,” he explains.

Looking back on his professional career, he recalls that “the great cultural leap in the world of design took place in the early 2000s, with the introduction of a probabilistic approach to safety and risk reduction at the regulatory level that better reflects physical reality and uncertainties.” Today, artificial intelligence increases computing power and speed and makes it available to everyone – software costs permitting – but it introduces a potential critical issue among seismic risk professionals: the temptation to rely on these systems not only for calculations but also for decisions on design strategies. “Even though there is no shortage of tools that provide answers, we need to be aware that they may be based on unverified, partial, or inaccurate data,” explains Pavese. “Some of the assumptions made by the algorithm are not the assumptions that a designer would make. Human reasoning is still necessary. AI should be used in areas we know well, otherwise, as in many other sectors, the risk of making serious mistakes is high in ours too.”