The bridge with extradosado prestressed. A new structural type

Abstract

The idea of ​​these bridges and their designation comes from Mathivat who, in 1988, proposes as a solution to the L'Arret-DarréW1 viaduct bridge with this typology, which is characterized by the provision of prestressing, on the support sections in stack , Externally to the edge of the section and to the upper part of the board, trying to gain eccentricity. Thus, it is a kind of tie-rod bridge with low pile and loose edge, which seeks, besides the compensation of loads, that the variation of stress in the steel of the extrados tendons, due to the overload, is sufficiently low so that the expensive fatigue resistant anchors used in the jumpers are not required.

The article illustrates the conception and development of this type of bridge from the evolution of the concept of load compensation by prestressing with steel tendons and the construction by cantilever advancement. It gives a presentation of the bridges built or under construction that can be cataloged within this type of bridge. In addition, given that the design philosophy of this type of bridges seeks to exhaust the possibilities of fatigue resistance of the external prestressing tendons, a summary of the existing literature review on fatigue in tendons and steel straps and their devices Support and anchorage. Finally, the main conclusions of the investigation are established