At 7:00 on June 20, the main girder of the double track grand bridge of Zangmu Yarlung Zangbo River Grand Bridge, Lhasa Linzhi Railway of Sichuan Tibet railway (short for Zangmuyajiang Grand Bridge) was shut successfully. So far, the main structure of 120 bridges along the entire line has been completed.

Zangmuyajiang Grand Bridge.  Photo by Jue Guo,  Xinhua News Agency

Located in Jiacha County, Shannan City, Tibet, the Zangmuyajiang Grand Bridge is the first railway bridge on the Yarlung Zangbo River, with a total length of 525.1 meters, a main arch span of 430 meters, and an altitude of 3,350 meters at the bridge site. It is currently the world's highest and largest railway steel tube concrete arch bridge.

The last concrete pouring of the bridge was successful. (Xinhua News Agency)

For the first time, Zangmuyajiang Grand Bridge adopted non coating weathering steel in the main structure of the railway bridge. The arch ring of CFST(Concrete filled steel tube) arch bridge adopted variable diameter design. The main pipe diameter changed from 1.8m to 1.6m, reducing the self weight by about 15%. It has also set two world records: the diameter of the main arch of the railway CFST arch bridge reaches 1.8m, and the concrete jacking volume in a single pipe of the CFST arch is 1022m³.

Part of the Zangmuyajiang Grand Bridge (Xinhua News Agency)

Chen Kejian, deputy chief engineer of CREEC, said that the bridge is located in the upstream reservoir area of Zangmu Hydropower Station in Sangda gorge. In view of the challenges posed by the crosswind of the gorge to the safe operation of the bridge, a new type of wind barrier has been created and developed. In the bridge deck, the crosswind is guided by the wind guide rails with a certain distance and blade angle to reduce the wind permeability to less than 50%, so as to ensure the train under Grade 11 wind has safe conditions for its operation.

Construction of the Zangmuyajiang Grand Bridge (Xinhua News Agency)

Lhasa Nyingchi Railway is the first electrified railway in Tibet with a total length of 435km and a design speed of 160km/h. It crosses the Yarlung Zangbo River 16 times, with complex geological conditions and a bridge tunnel ratio of 75%. During the construction process, a lot of innovations were seen in construction technology and management experience which will provide a leg-up to the developers of the upcoming Sichuan Tibet Railway (Ya'an Lingzhi section).（By Edina Liang）