Shin Chon Bridge, Korea

The new Iksan-Jangsu link through the mountainous terrain of South Korea's Jeollabuk-do province adds 61 km to the fast growing Korean expressway network of currently well over 3000 km. Shin Chon Bridge is a part of that new link. It carries the expressway at about 100-m height over a valley near Shin Chon village being immediately preceded and followed by tunnels. The bridge consists of two independent viaducts for westbound and eastbound traffic along different alignments, which run roughly parallel at a center-to-center distance of 50 m. The superstructures are posttensioned concrete box girders built by the balanced cantilever method with cast-in-place segments. All piers are monolithically connected to the girders and expansion joints are placed only at the abutments, which leads to semi-integral structures. These features necessitated a particular prestressing measure (i.e. longitudinal jacking of superstructures before casting the last key segments) and nonlinear structural analysis to verify the global stability of the flexible bridge systems and to determine the sectional forces and crack widths in the piers.