Graduation of Susana Sellés Valls

08 november 2019 14:00 t/m 16:00 - Locatie: Lecture Hall F, Faculty of Civil Engineering and Geosciences - Door: Webredactie

"A vine-based approach for defining critical infrastructure loads: Designing a breakwater in Galveston Bay, Texas." | Professor of graduation: Dr. O. Morales Nápoles, supervisors: Dr. E. Ragno, Ir. G. Smith, Ir. E. Moerman and Ir. A. Lioutas.

This thesis presents a methodology for defining infrastructure design loads accounting for their interdependence. The methodology is general and it is based on regular vines. Vines are graphical tools for defining high dimensional distribution function through pair-copula construction. With this premise in mind, the main effort was concentrated in formulating a series of steps to integrate several stages of the design: from the processing of raw data up to the choice of design loads for any specific design purpose. The vine-based methodology was applied to the design of two breakwaters in Galveston Bay, Texas. These applications showed that accounting for the interdependence between design variables provides a more comprehensive description of the physical system acting on the infrastructure. However, the vine-based method is computational demanding. Hence, the applicability of this methodology should be evaluated case by case. In parallel, exploratory work on goodness of fit based on the concept of tree-equivalent class (TEC) was done. This work led to the development of a (sequential) top-down algorithm. This algorithm uses the concept of TEC to extend best regular vine to higher dimensions without the computational burden of fitting all regular vine models. It allows the user to test a subgroup of regular vines and to select the best regular vine within that subgroup which is assumed to be the one with the lowest AIC. Despite the positive results achieved, this thesis only presents a step towards defining a goodness of fit for vine-copula that uses the concept of TEC.