Puente extradosado sobre el Río Barrow. Diseño y análisis estructural del proceso constructivo, control geométrico y asistencia técnica durante la construcción

Abstract

This paper describes presents the design and structural analysis required for the erection the bridge over the Barrow River in New Ross, Ireland. With two 230 m main spans  and an extradors deck with  three towers, including the crossing  over the Barrow River with an active navigation channel. The bridge has a total length of 890 m distributed in 9 spans. The construction processes of the bridge focused on the optimization of the project cost and programme. For this reason , two different construction processes have been used: • The approach spans on both sides of the extradosed main spans have been constructed in two phases from the sectional point of view. The core of the central box by means of a semi-rigid formwork to the ground for the central core and a second phase by means of a wing traveller for the side cantilevers and prefabricated slabs / strut.• The two main spans have been constructed by balanced cantilevers in the central tower and single cantilever front in the side towers, in both cases, with full-section form travellers were used. Due to the asymmetry of the towers and the  number of stays (18 cables in the central tower and 8 cables in the lateral towers) the cantilevers in both spans are not symmetrical, with the closing point being 140 m from the central tower and 90 of the lateral towers which required special care in the design of the closing stages. Also, in its maximum length of cantilever, the central tower reached 140 m in concrete supported by extradorsales cables, which constitutes a world record in this configuration.