PROBABILISTIC DESIGN OF RESTORATION SOLUTIONS FOR HISTORICAL BREAKWATERS: A CASE STUDY ON THE PORT OF CATANIA

A probabilistic design approach is proposed here for the design of restoration solutions of existing deteriorated rubble mound harbour breakwaters which are no longer able to ensure safety for port operations. The method allows one to consider both the stochastic nature of the variables involved in the wave-structure interaction (i.e. external loads, structure materials and geometry) and the uncertainties related to the imperfect knowledge of the physical laws that govern such a process. In this context, physical modelling represents a fundamental tool for the definition of site-specific formulations able to describe the response of non-conventional restored breakwaters to wave load, which may be different from the prediction of existing design formulas. The case study of the Catania harbour breakwater was chosen for the implementation of such a method. After defining an experimental damage progression formula derived from physical model tests on four upgrading options, the probability of failure during lifetime of each configuration was assessed, considering the limit states corresponding to initial damage, intermediate damage, and collapse of the armour layer.