Luís Simões da Silva

Cyclic performance of single and group micropiles on loose sand

An increase in the height of new generation of wind towers is foreseen in order to improve their performance. This will imply larger shallow foundations, which represent a substantial percentage of the overall budget. Consequently, it is of interest to develop alternative foundation solutions, with a smaller environmental impact, in particular in terms of the required volume of excavation and reinforced concrete. The proposed improvement consists in the use of micropiles placed along the foundation perimeter as a way to increase the overturning resistance of the system as well as the foundation behavior. The main focus of this paper is the characterization of the behavior of single and groups of micropiles, tested under controlled conditions. An extensive set of experimental tests were conducted on single and 2x2 groups of micropiles under monotonic or cyclic loading installed in loose sand. The effect of the cyclic loading on the behavior of the micropiles was assessed as well as the effect of the grouting on the improvement of the micropile resistance and stiffness and also on the improvement of the soil mechanical properties. The assembly and procedure of the tests are described and the corresponding resistance and stiffness are presented and compared.

RESISTANCE OF DOOR OPENINGS IN TOWERS FOR WIND TURBINES

In this paper, a study of resistance of a lower part of a wind tower including a door opening is presented. Nonlinear 3-D shell element models with real geometry of lower tower segment have been us ...

Computational Intelligence Modelling

The development of new materials and faster computing processes opened new frontier for the conception and development of new and audacious designs that will set the trend for the future 21th century structures. Various methods, techniques, and procedures have been, and still are being, used to improve and design these structures like optimisation processes, numerical modelling systems involving non-linear finite element analysis, etc. Concurrently, the last decade of the 20th century has been related to a large improvement and development of the so-called Computational Intelligent Techniques. These techniques are computational systems that try to mimic human behaviour, such as perception, reasoning, learning, evolution, and adaptation. They involve Neural Networks, Genetic Algorithm, Fuzzy Logic, and Hybrid Intelligent Systems , such as Neuro-Fuzzy, Neuro-Genetic, and Fuzzy-Genetic models .