China News Agency, Tibet, Gacha, June 20 Telegram title: The first completion of "One Crossing the Yajiang River" The Sichuan-Tibet Railway Lalin Section of the Zangmu Extra Large Bridge has set a number of records
Author Zhang Wei He Penglei
On June 20, the key iconic project of the Sichuan-Tibet Railway from Lhasa to Nyingchi (abbreviated as "Lalin Railway"), the Tibet Muyarlung Zangbo River Double-Line Extra Large Bridge (abbreviated as "Tibetan Extra Large Bridge"), the cast-in-situ main beam successfully closed, marking the pull At the same time that the construction of the main project under the Lin Railway is completed, it has also created and set a new record.
The reporter learned from the constructor of the Lalin Railway Project and the Tibet Railway Construction Co., Ltd. that the Zhummu Bridge is located in Gacha County, Shannan City, Tibet. It is the first railway bridge on the Yarlung Zangbo River with a length of 525.1 meters and the main arch With a span of 430 meters and an altitude of 3350 meters at the bridge site, it is currently the world's highest and largest span steel tube concrete arch bridge.
It is reported that the cast-in-place main beam of this Helong is the main component directly bearing the railway load of the Zangmu Bridge. It is a fully prestressed reinforced concrete box-shaped continuous structure. The total length of the beam is 517 meters, the bridge deck is 18 meters wide, and the beam weight is 19200. Ton.
For this reason, the construction party of the Zhamu Extra Large Bridge and China Railway Guangzhou Engineering Bureau Group Co., Ltd. constructed the cable hoist on the plateau for the first time, using the space long sling hanger method, and symmetrically cantilevered on the left and right banks of the Yarlung Zangbo River in sections. The front end of the hanger is anchored on a flexible sling with a length of about 100 meters. The maximum construction load of the hanger is 680 tons. At the same time, a 191-meter-long prestressed concrete beam is poured into each cantilever on both sides of the bank. The side-to-side opening error is less than 5 mm.
In order to cope with the high plateau environment such as high cold, large temperature difference, and strong ultraviolet rays, the survey and design team of the Zangmu Super Bridge, the China Railway Eryuan Engineering Group Co., Ltd. (referred to as the "China Railway Eryuan") and the relevant scientific research team proposed a complete set of railway coating-free weathering steel Technology, the first large-scale application of paint-free weathering steel structures on Chinese domestic railways, eliminating the need for paint anti-corrosion coating within 100 years of the bridge, not only reducing construction time, saving maintenance costs, but also extending the service life of the bridge.
Chen Kejian, deputy chief engineer of China Railway No. 2 Academy, said that the Zangmu Super Bridge is located in the upstream reservoir area of the Zangmu Hydropower Station in the Sangda Canyon. In response to the difficulties caused by the crosswind of the canyon to the safe operation of the bridge, a new type of wind barrier was innovatively developed and used on the bridge deck. Wind guide rails with a certain spacing and blade angle will guide the cross wind to reduce the air permeability to less than 50%, and ensure the safe operation of vehicles under 11 wind conditions.
In addition, the Zhamu Extra Large Bridge also adopts seismic isolation technology to reduce the structural safety problem of the bridge arch ring and pier seismic forces. At the same time, the main arch steel pipe of the bridge used the variable pipe diameter technology for the first time. The diameter of the steel pipe was changed from 1.8 meters to 1.6 meters, reducing its own weight by about 15%. It also created a steel pipe arch steel pipe with a diameter of 1.8 meters. Two world records of 1022 cubic meters of internal concrete jacking volume.
The length of the main line of Lalin Railway is 435.48 kilometers. It is the first electrified railway in Tibet with a design speed of 160 kilometers per hour. The total length of bridges and tunnels in the whole line accounts for nearly 75% of the total length of the line. It is expected to open for operation in 2021. As a key node control project of the Lalin Railway, the Zangmu Super Bridge is an exploration of the large-span bridge of the Plateau Railway. Its success in Helong means that the main works of the 120 bridges of the entire Lalin Railway are completed. (Finish)