(translated from the Italian by Google Translate, reviewed)
As after every destructive earthquake in Italy, the sequence of 2016-2017 has awakened the debates on seismic risk, on the safety of buildings, the relative costs, etc.
We discuss this with Gian Michele Calvi, who is professor at the IUSS of Pavia and Adjunct professor at North Carolina State University. He was the founder of the Eucentre Foundation and the ROSE School in Pavia; he is currently one of the directors of the International Association of Earthquake Engineering.
He coordinated, among other initiatives, the working group that drew up the text of the Ordinance PCM 3274 of 2003, which innovated the system of the seismic building code in Italy. He was president and member of the Commission of Major Risks, seismic risk section. He was accused, and subsequently acquitted “because the fact does not exist”, in the so-called “Great risks” or L’Aquila trial.
He has always worked to innovate the seismic design, concentrating mainly on masonry structures and bridges, isolation and design based on displacements over the last twenty years. He has published a large number of articles on the subject and received various international recognitions.
Is there something new on the horizon, according to you?
You know as well as me that there are chronic awakenings, which are repeated in a similar way since more than a century. In the specific case it seems to me that there is even more talking and less facts. Including the fancy “Casa Italia”, of which I confess I do not understand anything: tactics, strategy, goals.
The only moments in which I perceived real facts, directly or through the study of the history were:
- the incredible scientific and technical development that followed the Messina earthquake of 1908;·
- the rebuilding strategy after Friuli, where the production sector was more privileged than the residential one;
- the revolution of codes and seismichazard maps the earthquake of San Giuliano of Puglia in 2002;
- the construction of 186 isolated buildings in just over six months after the earthquake in L’Aquila.I know that the last two cases may appear as self-quotes, but that does not detract from the facts.
What I would like to see now is a change in the policy of intervention after an event, creating incentives for private action and progressive transition from the state to the loss coverage insurance system.
Hope, without optimism.
As for the built environment, the main problem seems to be the difficulty of knowing the vulnerability, or the factual situation, of each building. The City of Milan, a moderate danger zone, has made the static “fitness certificate” for buildings older than 50 years compulsory. Does this certificate have anything to do with the seismic problem as well? Moreover, after the tragedy of Torre Annunziata last summer, in which a building collapsed without an earthquake, Minister Del Rio announced that he wanted to re-launch the establishment of the so called “building folder”. What can you say about it?
I would not worry about the static or dynamic word: it is possible to do a seismic verification that compares a demand and a calculated capability both without time dependence, so “static”.
I realize that talking about demand and ability may seem mysterious. In fact all project or evaluation methods are based on comparisons of this type. For example, I can compare the strength of the structure and the force of inertia equivalent to seismic action, capacity and global demand for displacement, rotation capacity of a plastic hinge with motor-induced rotation, and so on. The problem is perhaps that, in fact, verification requires a comparison of a capacity and a question, which in some cases (the seismic in particular) are not independent of each other.
The minister, and many others, technicians and non-technicians, always seem to refer to the capacity alone, without wondering which actions they are to be confronted with. Only in extreme pathological cases this can work, i.e. when buildings have such low capacity to be inadequate, no matter in comparison to what.
I think instead that when you intervene on a building to improve its expected seismic response, it is right and possible to ask what damage is expected as a function of a motion intensity parameter. Today, the parameter used in the general case is the maximum acceleration of the ground (PGA), which is not particularly suitable for the purpose, as the correlation between expected damage and ground acceleration is rather modest. However, to begin with, we can also start from here: we can ask that each project, each evaluation, any improvement or adaptation action do include a diagram that correlates with PGA and expected damage, in terms of a percentage of the cost of reconstruction.
This is the “certificate” I would like and which would allow, in a virtuous system, to properly define the insurance premiums to pay, whoever pays them.
Why it is said that this certificate, which you do not like, should be made compulsory only in the case of a sale or hire of a new rent?
I believe that this certificate should first be made mandatory when there is a public resource contest in the intervention. The State finances, the State must ask to know the effectiveness with which its funds are spent.
Then I think that in such a case the State must also claim the insurance of the expected damages, at least for ground motions not exceeding those expected with a certain probability of overcoming. In such a context, the State would maintain its current role as a “last insurer”, but only when events with such low probability occur that could not be covered by the insurance system.
About buying, I think it should be the buyer to pretend to know what he buys, and be available to support at least part of the cost.
With regard to the rent, I believe that in a context where these assessments become widespread, the presence of such a certificate could become a beneficial element in concluding a contract: potential tenants could be asking for it.
With regard to the seismic aspects, is the problem mostly concerning the buildings without seismic design, or the whole of the buildings?
I would say that the first is more specific, but also all the others.
Standard codes have always been focused on one aspect: the probability of collapse, more directly associated with the probability of casualties. This is fine, and it should guarantee, if all was done well, that there will be a very small number of victims.
On the other hand, the correlation between collapse and expected damage in the case of a weaker ground motion, with a much higher probability of occurrence, is generally low, so that one could hypothesize a paradoxical situation in which no building collapses, but no building is habitable after an event and all require significant costs and time to be repaired and put into operation.
We could find it with buildings, bridges and infrastructures in general that have not collapsed but cannot be used or easily repaired, that is, with immense and unmanageable losses, with a production system unable to function, with the loss of any competitive capacity in the industry and in commerce.
We come now to the so-called “Sismabonus”. As pointed out by several colleagues, you have been the inspirator of this proposal. It seems to me that an operational proposal has been set up and that i remained in the drawers of the Minister until August 24, 2016. Is that so?
The first drafts of the document were certainly inspired and largely written by me in the autumn of 2013, as part of a Working Group made up of the Minister of Infrastructure and Transportation by Decree no. 0000378 of October 17, 2013. However, I would not dare to argue that the proposal was “operational”: it needed improvements and verifications, especially in terms of relation with professional and constructive practice.
Following the earthquake of Amatrice and the subsequent earthquakes the document was extracted from drawers and finalized at a high speed. How do you see its translation into operational law? Are there any real chances of success?
The document that came out is not perfect, and it could not be. It is also different from what I would have liked but it is certainly useful and marks the right path. The problem is how it is understood, transposed and used responsibly. What I mean is understanding its logic, not by applying it instrumentally to obtain unjustified tax benefits.
The pathetic inability of an important fraction of professionals (engineers, architects, geologists, geologists, etc.) to really understand the problems to be faced often induces to play hide-and-seek: designs are needed, evidence is needed, the characteristics of this and of that is needed. Often the conclusions cast doubts rather than give answers.
In this context it certainly does not help the progressive emphasis on aspects of criminal liability, rather than aspects of professional competence and moral responsibility.
An unclear aspect for the public is in what is – in fact – what actually represents one or more seismic risk classes less, that is, how much it increases the “security” of the building. First of all, I think it is not clear to everyone that the current earthquake building codes foresee – and thus admit – the possibility of collapse of a building, even with low probability. A common user wonders why – or at what price – this possibility is not eliminated.
First, there is a need to distinguish between probability of collapse (related to the “building security”) and expected losses, which can also be significant for a “safe” building. It is important to understand that a “safe” building is not so because collapse is impossible, but only in the sense that the probability that it will occur is lower than a defined threshold. Associating collapse to a zero probability is scientifically impossible, so the collapse event is always taken into account, albeit with low probability.
Even the value of this probability cannot be lowered indefinitely, because the associated costs would be socially unsustainable. It is a concept that applies to any sector: why do not you build cars that guarantee the lives of occupants in case of any kind of accident?
A minimum probability of collapse should be indicated by the codes (not explicitly) and guaranteed during the retroft intervention; is in fact a conventional value that is the subject of a sort of “social pact”. For example, in Holland it is conventionally established that the annual chance of having a victim caused by the collapse of a dam should be less than one in ten thousand.
Whatever this probability in Italy is due to seismic events is the subject of studies, but is not explicitly set forth in any document. As I said, it is on this point that standards are being focused, which should ensure the safety corresponding to the social pact I spoke about.
What they do not necessarily guarantee is the limitation of damages and losses. On this a private person should invest, guaranteeing a return on the economy within a reasonable time. On this, the state should develop incentive policies, guaranteeing lower costs over time with modest initial expense.
Moving one or more classes refers to expected losses. With regard to tax benefits, if expected losses, which may also refer to non-structural problems, decrease, you go to a better class. Clearly, collapse and losses are characterized by related parameters, so improving one improves the other, but from a logical point of view the two themes can be handled independently.
The concept of expected losses may perhaps be better understood by referring to the theme of energy policies. The energy class of a building refers to the annual cost expected for heating and air conditioning. The seismic risk class could refer to the average cost incurred to repair the damages and indirect or indirect costs they incur. The difference lies in the fact that while energy spending varies little year on year, that seismic can be zero for years or decades and then in a certain year to be very high. Talking about average annual losses means substantially dividing the costs related to that one year on all the previous years when no significant ground motives occurred.
I remember that there is a lot of confusion around how the seismic “retrofit” and “improvement” terms are adopted. Can you explain it?
“Retrofit” and “improvement” refer to the probability of collapse, which in the first case becomes at least equal to what is foreseen by the rules for newly built buildings, while in the latter case it may be higher, it must only be less than that which characterizes the “building before the intervention.
In other words, regarding rules and chances of collapse:
• The accepted probability of collapse is set by the codes
• if, after an intervention, the probability falls below this value, it is retrofitted
• If the probability drops but does not reach that value, there is improvement.
After each earthquake, estimates of how much resources would be needed to “secure all the country’s homes” are presented. I listened to it since 1980 at least. After the estimates the debate (immediately closed) comes on how to find the resources. Should not the owners also take care of it? Yet owners feel that they the State should take care, and the latter does not seem to say no. Guilt feelings? And for what fault?
You’re perfectly right, they’re all words in the wind.
I fear that the fundamental problem lies in the common perception of the State as the ultimate insurer, without capacity constraints, and above all equally generous with those who worked well and with those who were not concerned about the problem, even with those who built abusively or without respecting the standards.
I would see a logical scheme of this kind:
• The State defines important tax benefits for those who improve the expected behavior of their property
• In conjunction with obtaining tax benefits, the state requires the definition of a correlation between ground motion parameter and expected losses
• At the same time, it obliges those who get the benefit to contract an insurance, characterized by a predetermined cost based on the expected losses, which provides for a payment corresponding to the expected losses.
In such a context, the State could also agree on soft loan schemes where banks would directly benefit from the tax benefits of citizens.
I do not believe that politicians feel guilty: on their desire to work for immediate consensus rather than with far-sighted logic, yes, I do believe.
The issue of the “building folder” or the “static certificate” is repeated – more commonly in Italy – after some collapse (eg Torre Annunziata) or catastrophe (Ischia). Minister Del Rio admitted that there is a lobby opposed to such initiatives. Is it the same lobby that has been opposing for years since the introduction of earthquake damage insurance, as in all “most civilized” countries, or is it another lobby?
I do not believe in lobbies, big old people, strong powers, or any convenient newspaper formula. It’s just a question of intelligence and determination. It seems to me that I have already answered: it is only about seeking vows, myopia, lack of civic sense and stupidity.
Also about the insurance obligation I have already expressed: everyone is already paying it, with the taxes we pay to the Insurer-State. I would make it compulsory only in the case of tax benefits. On the other hand, I would clarify that the state will intervene only when the ground motion parameter recorded at the base of a building (today’s maximum acceleration on the ground) has been higher than the standard value, plus a tolerance threshold that could be defined in the order of twenty percent.
As I have already pointed out, this value should correspond to a social pact, which seeks a reasonable compromise between the resources that can be invested and the security of the building. Any project acceleration value is fixed can be exceeded from a probabilistic point of view, but as the value increases, costs can grow unreasonably, or in a way incompatible with sustainable expenditure.
It seems to me that that you accept the idea that the State still has to bear a substantial share of the reconstruction costs. In general, however, it tends to believe that such coverage is derived from “ordinary” taxes, while these costs make heavier, and not least, the national deficit. Why not hope for a change that puts us at the same level as the most “civil” nations?
Any imposition of checks in this country is understood as a form of tax, an additional, unjustified and unnecessary cost, an inconvenience to incapable technicians.
The State should act by promoting expected cost reduction policies, understanding that it is directly the ultimate beneficiary of a more resilient country, less susceptible to damages and losses.
We need to develop incentive policies for virtuous behaviors, creating emulation.
Finally, what are the missing arguments for a seismic risk reduction policy, and what are our hopes?
I wrote several responses. Then I deleted them, one after the other.
I fear that we cannot speak of any social hope, only of responsible individuals.
It’s not a cultural question, it’s a moral question, as Enrico Berlinguer said, time ago.