Namhangang Railway Bridge – A Series of Normal and Underslung Arches

Namhangang Railway Bridge is a series of arches, and 480 m long with 5 spans. It consists of three normal and two underslung arches. By putting normal and underslung arch in serial and giving variable rise ratio, ‘wave’ impression and similarity with famous monuments has been derived. The 1st, center and 5th span is 100 m, 120 m and 100 m, respectively, while the underslung span is 80 m in between. Height of arch is taken as 18.0 m for 100 m span and 25.5 m for 120 m span, respectively. Hangers with 7.5 m spacing are given positioned in radial direction. Depth of underslung arch is 8.0 m, where diagonal strut is provided. As result of detailed rail structure interaction study, a proper dimensioning of substructure has been made. From dynamic performance analysis, satisfactory performance has been verified. Erection of arch has been done by block by block on temporary trestle and completed in 2018.