The Huasco Bridge was completed in 2011 as part of the widening of “Ruta Norte 5” road between La Serena and Caldera, in northern Chile. This road is part of the Pan-American Highway, which stretches across the entire continent. This bridge was necessary to add two more lanes to the existing road. It spans the Huasco River valley, with an overall length of 200 m divided into three continuous spans, whose lengths are: 42+116+42 m.
The deck consists of a single-cell, post-tensioned concrete box girder with a variable depth between 2.5 and 6.5 m. At 22.3 m in width, it is one of the widest ever built for this structural type, and accommodates four road lanes plus shoulders. The deck is rigidly connected to the two piers, forming a frame; whereas at the abutments it is supported by POT bearings and high strength bars.
Due to the significant height of the bridge, and to minimize the construction effects on the river bed, the balanced cantilever method was selected. This construction method requires careful displacement prediction and control, and for this reason advanced bridge design software was used (RM Bridge). Since the width of the deck is approximately 20% of the main span length, 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.Roads & Bridges, October 2012