Composite modelling of the Pont del Petroli pier failure due to extreme sea waves during the winter storm Gloria

On January 20th, 2020, the storm Gloria caused the collapse of the final part of the walkway that connected the seaward platform of the Pont del Petroli pier to the beach of Badalona (Spain). A stretch of about 15 meters fell into the sea due to strong impacts caused by a long-lasting wave action. A composite-modelling approach is proposed herein to reproduce the specific conditions that led to the failure of the pier. The goal of the work is to reconstruct the specific maximum wave conditions caused by Gloria and to provide information on the ultimate resistance of the pier structural elements. The meshless SPH-based DualSPHysics code has been employed for a preliminary characterization of the loads exerted on each pier element by extreme wave conditions representative of Gloria. Numerical model results have been employed for the setup of the experimental campaign carried out in the large-scale wave flume facility CIEM at UPC in Barcelona. Bathymetric surveys carried out before and after the storm showed a radical change in the bottom bathymetry at the toe of the damaged area of the structure, with sand accretion and reduction of water depth from 10m to 8m, approximately. This heavy change is expected to affect the wave transformation and breaking right before the structure quite significantly. For experimental and numerical modelling, a wide range of extreme individual wave impacts have been generated by means of focused wave groups. The results from the physical model provide a new insight on the forces experienced by the pier during storm Gloria.