The Huasco Bridge is part of the new “Ruta Norte 5” road between Vallenar and Caldera, in northern Chile. The bridge crosses the Huasco River valley, with an overall length of 656 ft (200 m). The deck is a continuous girder of three spans
137+380+137 ft (42+116+42 m).
The bridge was built using the balanced cantilever method, with the deck rigidly connected to both piers, forming a frame. At the abutments, the deck is supported by POT bearings and high strength bars. The cross section of the deck is 73 ft (22.3 m) wide, which is one of the widest for this type of bridge, and consists of a single-cell, post-tensioned concrete box girder with a variable depth of 8 ft to 21 ft (2.5 to 6.5 m).
Due to the significant height of the bridge, and to minimize the construction effects on the riverbed, the balanced cantilever method was selected. This construction method requires careful displacement prediction and control, and for that reason advanced bridge design software was used (RM Bridge).
Since the width of the deck is approximately 20% of the main span, important shear lag effects were considered in order to correctly predict the stresses and displacements of the bridge in every phase of construction.
Ferraz, R; Sobrino, J; Betancour, N.; Puente por voladizos sucesivos en Huasco, Chile (in Spanish), V Congreso de ACHE, Barcelona, 2011.