Phd in STRUCTURAL AND GEOTECHNICAL ENGINEERING

Thesis title: Performance-Based Multi-Hazard Engineering for Structures

In recent years, multi - hazard scenarios involving civil structures have become more and more frequent: for this reason, it is necessary to overcome the concept according to which structural design must consider different hazards separately and move towards a multi - hazard design. Taking into account some of the possible types of interaction between hazards and the issues that arise when the structural problem is addressed in a multi-hazard context (including the necessity to merge within a unified risk assessment framework the methodological approaches used for different hazards and the possible conflictual design strategies for different hazards), aspects related to structural performances in a multi-hazard environment (Performance Based - Multi Hazard - Engineering - PB-MH-E) will be discussed, highlighting how this type of approach is essential to identify criticalities and advantages of design choices in order to ensure a better behaviour of the structure, especially when multiple hazards act on it. In the first of the two applications the performance of plane steel frames subjected to seismic and wind loads will be assessed, extending to the wind the probabilistic approach SAC-FEMA, widespread in a seismic environment, with the aim of identifying a procedure that allows to express in the same language the performances of the structure for both hazards considered. The second application, instead, will be focused on the evaluation of the effect on the structural robustness of the concatenation of events such as earthquake - explosion (hazard-chain interaction related with the so-called Low Probability - High Consequeces events), assuming that the first hazard harms the structure thus altering its performance when the second hazard occurs.