Chongqing - On December 28, Chongqing Rail Transit Line 18 officially commenced trial operation, with the overall general contracting design undertaken by the joint efforts of T. Y. Lin International Engineering Consulting (China) Co., Ltd. from the Liangjiang New Area, setting multiple "firsts" and achieving numerous national and even world records in the field of rail transportation.

On December 28, Chongqing Rail Transit Line 18 officially commenced trial operation. (Photo/T. Y. Lin International Engineering Consulting (China) Co., Ltd.)

Shi Ningqiang, general manager of the Rail and Underground Space Business Division of T. Y. Lin International Engineering Consulting (China) Co. Ltd, emphasized adherence to an international, green, intelligent, and humanistic design philosophy during the project's design phase in an exclusive interview with Bridging News.

"This project stands as Chongqing's first rail line designed using Building Information Modeling (BIM)," said Shi. BIM is an intelligent, 3D model-based tool that provides a digital representation of a facility's physical & functional aspects.

Shi Ningqiang, the general manager of the Rail and Underground Space Business Division of T. Y. Lin International Engineering Consulting (China) Co. Ltd. (Photo/T. Y. Lin International Engineering Consulting (China) Co. Ltd.)

Shi added that leveraging the BIM model from the design phase for intelligent simulation in construction, including process simulation, node arrangement, material guidance, and 3D visual briefings, these steps boosted resource efficiency, improved quality, and accelerated progress.

In the operational phase, the BIM model facilitated equipment management by providing a data foundation for functions such as equipment health monitoring and fault impact analysis, ultimately reducing equipment depreciation rates and maintenance costs, Shi stated.

World's largest public rail-trail steel truss cable-stayed bridge

The Baijusi Yangtze River Bridge, key to Line 18, holds the record as the world's largest public rail-trail steel truss cable-stayed bridge, boasting a total length of 1384 meters, with a principal span extending an impressive 660 meters at a height of 236 meters.

The Baiju Temple Yangtze River Bridge adopts an innovative trapezoidal truss section and an inverted trapezoidal truss beam design to meet the different width requirements for road and rail on two levels. 

"This employs a collaborative design approach, significantly saving on investment," Shi explained.

This also marks the first use of ultra-high-performance concrete in bridge towers, countering concrete cracking from age-related shrinkage and temperature changes over 24 months.

Baijusi Yangtze River Bridge. (Photo/T. Y. Lin International Engineering Consulting (China) Co., Ltd.)

China's first large-span steel box girder cable-stayed bridge

The Lijiatuo Yangtze River Double-track Bridge, Chongqing's first, serves Metro Line 18's cross-river transport needs.

Spanning 991.7 meters, the bridge uniquely combines a four-lane road and double-track rail on the same level in a non-symmetrical arrangement, a first in China for large-span steel box girder cable-stayed bridges.

According to Shi, the design team of the Lijiatuo Yangtze River Double-track Bridge proposed the design concept of "Rebirth," considering the bridge's location and urban landscape.

The new bridge adopts bridge towers mirroring the appearance of the old bridge, which has been in service for over twenty years. The design team's color coating strategy integrates the new and old structures without compromising the original bridge's integrity.

Careful consideration of color combinations highlights the three-dimensional sense of the structure through linear elements. "The parallel existence of the new and old bridges symbolizes the boundless vitality of Chongqing's future," said Shi.

The bridge is designed for dual-use of road and rail, meeting transportation needs and matching the route design on both banks. Given urban landscape needs, it features a single-layer deck with road and rail on the same level.

Shi highlighted that the bridge, tailored to functional and aesthetic demands, is a double-tower, double-cable, steel box girder cable-stayed structure with a 454-meter main span. Its unique asymmetric main girder layout makes it China's largest-span bridge, with road and rail co-located on the same level in a non-symmetrical design.

Lijiatuo Yangtze River Double-track Bridge is the first double-track cross-river bridge in Chongqing. (Photo/T. Y. Lin International Engineering Consulting (China) Co., Ltd.)