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The project marks a new phase of development of Risk Map Information System addressing the issues of the hazard and risk of monuments, not just within the three domains (static-structural, Environmental - air, anthropogenic) that have characterized the start of the system from the 90s, but also by higher detail in seismicity.
In order to determine new models for the calculation of seismic risk, the indicators of seismic hazard, updated to new legislations, have been made in relation with the data of vulnerability and exposure derived from the new form of seismic vulnerability (VS).
The new data form has been differentiated for 3 different types grouped by synthetic conditions (1-palaces, 2-tower/belltower, 3-church/theatres/building complexes). The reason for the choice of the 3 types mentioned lies in the specificity of the vulnerability models (feasible only for those types).
The main aims were those of an initial survey on a limited sample of monuments in Sicily and Calabria, which has affected a total of about 3150 monuments. On these monuments, detailed aspects of earthquake-constructive anamnesis and the survey of micro tremors measurements response to environmental noise have been even more performed.
Survey and form are to be quickly done and have followed, as possible, suggestions of “Guidelines for assessment and seismic risk reduction on cultural heritage, with reference to technical code for constructions”, now “Technical Law of Premier” on October 12, 2007. This is a further reason for looking at the proposal as a first step for deepings survey and technical screening according the above mentioned Law.
SYNTHETIC REPORT PROJECT:
The survey of seismic vulnerability has allowed the testing of two different models of vulnerability assessment and seismic risk:
Evaluation of seismic vulnerability by 3 - classes system (high, medium, low).
On the bases of information acquired by a quick assessment survey, particularly on some constructive details and damage types, an evaluation of seismic vulnerability on 3 different levels (high, medium, low) can be performed.
The logic of this assessment is a classification of the historical heritage through different vulnerability levels (high, medium, low), according to the expected effects in terms of damage and collapse. The assessment leads to separate the cases where the vulnerability lies in an intermediate level (medium-low), due to the necessaries caution on a quick survey.
For the monuments that are very vulnerable, a brief description of the possible damage types and their causes, can be performed. The cases where the mechanisms of damage are presumably limited to parts of buildings have been highlighted.
A degree of reliability of the assessment is also shown.
As for the survey, one can look at this proposed classification as a first step of more detailed analysis and retrofitting operations.
Evaluation of seismic vulnerability with a decision-making support system
The evaluation of an asset’s seismic vulnerability is obtained by means of the application of a data collection decision-making support system comprising straightforward forms together with microtremor measurements performed on well-studied foundation grounds.
The system performs a series of paired data combination comparisons, normalised as compared with the maximum values assumed by each variable in the whole data base. The elements of the decision-making tree are compared each time with an appropriate weighing system, which can be modified by the user.
The final results of the calculation of all the assets filed and appropriately ordered, has allowed us to establish three main classes of vulnerability: high, medium and low, besides a medium-low vulnerability sub-class.
Within the discreet class division, for each asset the system nonetheless maintains its respective numeric value of vulnerability, thereby allowing us to distinguish between assets having different vulnerability even within the single classes, in order to make preliminary estimates to prioritise the measures addressed to risk reduction.
