The Pitan Bridge, Taiwan

To alleviate traffic congestion near Taipei, in 1985 the Taiwan Area National Freeway Bureau planned the construction of the 108 km long Northern Taiwan Second Freeway. The majority of the Second Freeway's alignments are on grade, on embankments, in tunnels, or on viaduct structures. At several locations however, obstacles were identified that required special bridges. The Pitan Bridge spans one of these areas. The Pitan Bridge, actually two nearly parallel bridge structures, is located about 15 km south of Taipei. It connects typical low-level viaducts to a tunnel. Both bridge units have total length of approximately 800 m, a 750 m radius curvature and a slope of approximately 1%. The structure as designed and built makes use of the well-established economy of a segmentally erected post-tensioned concrete box girder bridge, adapted for the site with the innovative use of delta-shaped piers of post-tensioned concrete construction.