Strait crossings

Abstract

The construction of fixed links to cross straits has meant a link of union between lands and people. Strait crossing options are solutions devoted to cope with difficult geography so that the progress on this subject comes as an answer to the "challenge of the geography." Strait crossings require a multidisciplinary approach, not only from the civil engineering view. Fixed link solutions have a relevant incidence on the environment and affect the social and the economic development of the area; moreover, these works provide mobility as a safety factor. The decision whether the strait crossings are to be made by fills, bridges, floating bridges, submerged floating bridges, immersed tunnels, immersed floating tunnels or bored tunnels depends on the factors such as; technical feasibility, costs involved, aesthetics and environmental conditions. By looking at technology of strait crossings over periods of 4,5 or 6 decades one can see and appreciate the developments that inevitably occur in structural forms, construction materials, method of connecting materials, method of structural analysis, construction techniques and aesthetics. Although the trend is towards the development of fixed links, this is not an option of "all or nothing" and a compromise, a balance has to be achieved between the fixed links and ferries. That is why it is considered essential to pay special attention to the strait crossings' planning.