Pingtang Bridge Design Shines at the 2016 London Infrastructure Construction Summit

Release time:

2016-12-19 08:45

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Recently, the multi-option comparative design for the Pingtang Bridge on the Pingluo Expressway—specially designed by our company—made a stunning debut at the 2016 London Infrastructure Construction Summit. At the awards gala dinner of the summit, Bentley announced the winners of the 2016 Be Innovation Awards, and the multi-option comparative design for the Pingtang Bridge on the Pingluo Expressway was named a finalist for the 2016 Be Innovation Award.

The Pingtang Bridge has a total length of 2,135 meters and its tallest main tower stands at 328 meters. Upon completion in 2019, it will become the world’s tallest reinforced concrete bridge tower. The bridge will connect the Yinlong and Lanhai national expressways, reducing travel time between the two banks of the Caodu River canyon by at least one hour. This three-tower, double-cable-plane cable-stayed bridge—with towers reaching a maximum height of 328 meters and main spans of 2 × 550 meters—features a structural system with relatively weak stiffness. The key technical challenges in its design include: First, the force characteristics of a three-tower cable-stayed bridge differ significantly from those of a conventional two-tower cable-stayed bridge. Specifically, the middle tower lacks both auxiliary piers and transition piers on either side, meaning it cannot provide effective constraints on the main span beams. Moreover, the influence lines for live loads on various structural responses are considerably wider, resulting in much greater deflections of the main beams, larger stress amplitudes in the stay cables, and higher bending moments at the base of the towers compared to a two-tower cable-stayed bridge. Second, given that all three towers of the Pingtang Bridge stand approximately 300 meters high, how to enhance the overall structural stiffness, control the fatigue stress amplitudes in the stay cables, and meet the load-bearing requirements of the towers, beams, and cables represents another critical design challenge. During the design process of the Pingtang Bridge, the company conducted in-depth analyses and comparative studies across multiple technical challenges—including the placement of auxiliary piers, the layout of the cable systems, the matching of tower stiffness, and the selection of tower-beam support systems—and adopted a variety of combined measures to effectively increase the structural stiffness, providing a comprehensive set of solutions to ensure the safety of the bridge structure. Ultimately, the bridge design adopted a multi-tower cable-stayed bridge support system featuring “hinged connections between the middle tower and the beam, and vertical supports for the side towers.” The study concluded that “increasing the stiffness of the middle tower is an ideal approach to improving the overall structural stiffness,” thereby avoiding the extensive excavation required for anchorage systems in large suspension bridges and minimizing the environmental impact on the surrounding area.

In recent years, Guizhou Province’s transportation sector has achieved leapfrog development, bringing tremendous benefits to society and placing higher demands on the design technologies for roads and bridges. Our participation in this London Infrastructure Construction Summit has profoundly highlighted how BIM innovation is gradually making its way into infrastructure construction within the transportation industry, with real-world modeling increasingly becoming the mainstream approach in design. Engineering applications based on BIM technology are enhancing both the quality of design and operational efficiency in transportation infrastructure. By creating and leveraging digital models throughout the design, construction, and operation phases of engineering projects, we can effectively avoid information silos, boost work efficiency, conserve resources, and reduce costs—thus paving the way for the integration of green technologies and infrastructure development. (Chen Yinggao)