Dagu Bridge

The steel box tied arch bridge is the first of its kind in the world and represents a major achievement in bridge engineering.

The visually striking asymmetrical design for the Dagu Bridge is called “Sun and Moon Arches.” The larger, 39-meter-high arch faces east and symbolizes the sun, while the smaller, 19-meter-high arch faces west and symbolizes the moon. The larger and smaller arches incline outwards by 18° and 22° respectively.

A tied arch structure was selected for the 106-meter main span. The bridge carries six lanes of traffic and two pedestrian paths, with a width that varies from 30 to 60.8 meters. 

The Dagu Bridge is in Tianjin’s urban Consumer Recreation District (CRD) and crosses the Haihe River where the river is close to 100 meters wide. To provide sufficient headroom for sightseeing boats to cruise the river, the maximum depth of the bridge girder is only 1.3 meters at the navigation opening.

Project Highlights:

• Each arch rib has a three-dimensional structural system using two planes of hangers.
• The deck loadings are distributed to the inclining high/low arch ribs through the spatial tie rods. 
• The spatial tie rods within the arches form multi-point supports to the cross beams and meet the requirements for “Rigid Plate Bridges” of this size.
• TYLin exploited the transverse rigidity of the cross sections and the vertical rigidity of the arches to give the slender-looking bridge a high resistance to earthquakes in the region.