Conceptual Design of the Cable Stayed Miradoiros Bridge in La Coruna (Spain)

The city of La Coruna is located in the northwestern coast of Spain on the Atlantic Ocean coast. The total population comprising the surroundings is about half a million of inhabitants. The most densely populated part is in an isthmus, thus conventional roads on the narrow mainland have reached a high level of traffic congestion. As a consequence, there is a social demand for alternative routes joining the city downtown and the residential areas around it. Therefore to solve this traffic problem the local authorities demanded the authors to elaborate the conceptual design of a bridge spanning the La Coruna Bay in order to improve communications of the main city with the growing areas at the North in the other side of the bay. The targets of the conceptual design work have comprised the evaluation of the most adequate location of the bridge, the study of alternatives and the final decision of the typology, the geometrical definition of the towers and the deck and the layout of the road to connect the bridge with the pre-existing communication network. As a matter of fact, this work has offered a great occasion to apply non-conventional tools in the bridge design process. Computer renderings have been done since the initial steps of the design work in order to verify the aesthetic values of the proposal. CFD has been employed to evaluate the aerodynamic coefficients of the deck cross-section in order to anticipate the aerodynamic and aeroelastic performance of the bridge. Moreover, the optimization of the cables cross-section of the cable-stayed bridge has been carried out considering constraints associated with the cables stress and the deck displacements. In this paper the final definition of the proposal is presented, describing the cable stayed bridge selected after the alternatives studied and significant attention is paid to the set of design tools employed along the design process.