Development of a framework for the regional vulnerability assessment of RC buildings: an automatic tool based on typological-mechanical modelling and non linear time history analyses

In the present work an all comprehensive framework for the seismic vulnerability assessment of existing Reinforced Concrete buildings at a regional scale is proposed and developed. Proposed approach belongs to the typological-mechanical class of strategies, and draws inspiration from several of the existing approaches belonging to the same class, borrowing what are considered the best characteristics of each existing proposal. The main goal of this proposal is attempting to tighten the gap between the deepening level, and hence reliability of results, between the individual building and the regional scale, within an all comprehensive framework. It is worth highlighting that it is infeasible the use of deepened methods for the regional scale as it is common for individual buildings. The issue of feasibility is due to two main reasons: • it is impossible to reach a sufficient knowledge level for the whole building stock in a region, as on the contrary it can be made for a single building; • deepened analyses (as non-linear dynamic that will be here used) require a cumbersome effort in terms of computational cost, to a point that it could be considered uneconomical. For the first issue, a deepened statistical framework will be used for all unknown parameters, thus with the help of real data in order to calibrate parameters values for better adherence to the building stock under analysis. An increased variability of results is clearly expected, while the error introduced by the statistical procedure will be reduced as much as possible by increasing the number of analysis runs. The second issue is probably the reason why most of the researchers, engaged in regional scale vulnerability assessment, resort to various degrees of simplifications. In the development of the proposed procedure this issue is assumed to be not critical:computational cost is considered not crucial, while the development of a working tool will represent the proof of its feasibility. One of the desired features of the proposed approach is its agility, i.e. the ability to be easily modified when needed (as soon as the modification does not regard the core characteristics of the implemented method). The procedure will be developed in order to be organized in modules, according to an object-oriented programming philosophy. It is worth highlighting that, for its agility, the proposed procedure will not be indissolubly connected with any of the cited modules, neither with assumptions and simplifications that will be used in order to retrieve some example results and test the feasibility of the idea: the procedure is completely open to modifications and enhancements. Also the meaning of enhancing the procedure is blurry: depending on the underlying needs, a given edit could represent an improvement or a worsening. For two crucial elements of the procedure a novel solution will be presented: the beam model and the time integration strategy. On the other hand, in other modules simplifications will be introduced, postponing further insights to future developments. Regarding the first element, a novel beam model will be proposed in order to get rid of some mathematical incongruity of existing models. Once presented, the model will be then used into the procedure in order to more effectively model the behaviour of structural elements. About the time integration strategy, a novel approach in this field will be proposed. For instance, the exactness of the solution provided by this approach will be discussed, together with its uniqueness. Once the proposed framework will be implemented into a tool, some example applications will be presented, in order to assess its reliability and clarify its feasibility.