China News Service, Kunming, November 12 (Reporter Miao Chao) According to China Railway Kunming Bureau Group Co., Ltd., the construction of the No. 9 lattice pier of the Nanxi River Super Bridge on the Wenshan-Mengzi Railway in Yunnan (referred to as the "Wen-Mengzi Railway") was completed on the 12th. This is the first time that the "lattice pier" structure has been used in China's railway engineering, marking China's important technological breakthrough in the field of high pier bridge construction in mountainous areas.
The Nanxi River Super Bridge is located in Zhicun Town, Mengzi City, Yunnan Province. It has a total length of 789.71 meters and a maximum height difference between the bridge deck and the ground of 118 meters. It is the highest bridge on the entire Wenmeng Railway.
The bridge is located in an area with sharply undulating terrain, spanning deep ravines, and unfavorable geology such as dangerous rockfalls and karst development, making construction extremely difficult. Therefore, a total of 3 lattice piers were designed for the whole bridge. Among them, pier #9 is 105 meters high and is the highest pier on the entire line. The lattice structure is divided into 7 segments/176 pieces of assembly technology. The largest single component weighs 24 tons, which is like "building giant building blocks" at a height of 100 meters.
According to the relevant person in charge of the Southern Yunnan Railway Construction Headquarters of China Railway Kunming Bureau Group Co., Ltd., the concrete-filled steel tube lattice pier used this time is assembled into a trapezoidal pier with "wide at the bottom and narrow at the top" through steel pipes and I-beams. High-strength concrete is poured inside, which can save 30% to 50% of concrete and steel. At the same time, the prefabricated assembly process greatly reduces on-site pollution and construction risks, improves earthquake resistance and geological adaptability, and realizes the multiple values of cost reduction, efficiency increase, low carbon, and safety.
Cui Zhenxi, head of the first three bids project department of the China Railway 18th Bureau Wenmeng Railway Station, said that in order to ensure millimeter-level assembly accuracy of the 100-meter-level lattice piers, the project team specially laid out a high-level measurement control network, equipped with high-precision measuring instruments, and arranged a professional measurement team to conduct precision stakeout; during the construction, special technologies such as guide positioning and dynamic fine-tuning were simultaneously used, and multiple measures were taken to strictly control installation errors to ensure that the assembly accuracy of the guardrail fully meets the design standards.
The successful application of this lattice pier and the complete set of design, construction and full life cycle operation and maintenance technologies developed through this research are expected to provide a standardized technical model for other railway projects.
The Wen-Mongolia Railway is approximately 116 kilometers in length and has a designed running speed of 160 kilometers per hour. It is China's national Class I dual-line passenger and freight electrified railway. It is an important project of the southwest border railway in China's medium- and long-term railway network planning. After completion, it will further improve the structure of the road network in southeastern Yunnan and facilitate the travel of people of all ethnic groups along the route. It is of great significance to promoting high-quality economic and social development in border and ethnic areas and serving Yunnan's high-level opening up to the outside world.
