Steel Structures of Jiangning Super-large Bridge on Ningma High-speed Railway in Nanjing Jiangsu Province

■ The main bridge is a 128 meter span inner inclined basket arch super large bridge, and the main arch rib section is dumbbell type concrete-filled steel tube truss.

■ The arch rib inclines to the center line of the bridge axis with an inclination of 9 °, which is a spatial curve. The distance between the centers of the two arch ribs at the arch foot is 16.2M, and the arch rib is 2 - φ 1200mm steel pipe with a wall thickness of 18mm.

■ Two steel pipes form a dumbbell shaped section, which is connected by battens. The thickness of battens is 16mm. C55 non-shrinkage concrete is poured into the main steel pipe and battens.

■ There are 5 transverse braces between the two main arch ribs, among which i-brace is set at the arch crown and k-brace is set for the rest.

■ The main arch rib is connected with the reinforced concrete beam through the suspender, the upper end of the suspender is anchored at the top chord of the arch rib, and the lower end is anchored at the concrete tie beam.

■ The main steel material is Q345qD plate, with the maximum welding thickness of 18mm. Adopt section hoisting technology and construct under the condition of continuous traffic of expressway.