Description

As a crucial controlling project of the Jinyang-Ningnan Section JN4 Bid of the G4216 Yibin-Panzhihua Expressway, Duoping No.1 Bridge is constructed by the Second Company of China Railway No.4 Engineering Group Co., Ltd. The total length of Duoping No.1 Bridge is 545 meters. It adopts a composite structural system consisting of simply-supported T-beams, prestressed concrete continuous rigid frame and simply-supported T-beams. With a deck width of 12.6 meters and a design speed of 80km/h, the bridge is designed as a two-way single-lane expressway structure. The main span of the bridge reaches 130 meters, and the left and right continuous rigid frame girders are constructed independently. The No.5 and No.6 main piers are box-type piers with heights of 57.5 meters and 45 meters respectively. The combination of high piers, large-span structures and complex canyon terrain brings extremely high difficulties to construction management and control.

The continuous rigid frame girder of the bridge adopts a single-box single-cell, variable-height and variable-section straight web box girder design, with a total left and right girder length of 536 meters. The overall girder construction is divided into 150 pouring segments. The cantilever segments are constructed by the form traveler construction method, and the cast-in-place side span segments are constructed by the bracket construction method. The project features complicated working procedures and stringent requirements for linear control accuracy and concrete pouring quality. In addition, the construction team overcame multiple challenges including high pier concrete pouring difficulties, canyon wind disturbance, limited construction site and safety control risks caused by adjacent residential areas, which put forward extremely high standards for construction technology, equipment performance and on-site management.

Boyoun form traveler equipment was applied in the core construction process of the bridge's cantilever continuous girder. Equipped with stable structural bearing capacity, precise linear fine-tuning system and reliable safety protection configuration, the equipment is highly adaptable to the complex canyon working conditions of the project, including 150 variable-section segments and high-altitude cantilever operation. It ensures accurate girder pouring linearity and controllable construction safety throughout the process, efficiently supporting the standardized and high-quality construction of continuous girders and providing key equipment guarantee for the on-time closure of the bridge.

The right-span continuous girder of the bridge was successfully closed on July 21, 2024, and the full bridge achieved complete closure on October 4, 2024. The successful completion of the two key construction nodes fully verifies the scientificity of the project's construction scheme and the high adaptability of the supporting construction equipment.

As a throat controlling project of the Jinyang-Ningnan Section, the closure of Duoping No.1 Bridge has completely broken the key construction bottleneck, provided a complete working surface for subsequent T-beam erection and transportation, bridge deck pavement and auxiliary works, and effectively accelerated the overall construction progress of the expressway.

Upon the full completion of the Yibin-Panzhihua Expressway, it will connect with the Jinsha River waterway and the G85 Yinchuan-Kunming Expressway to form a comprehensive three-dimensional water-land transportation system. The project will greatly improve the transportation capacity of the Chengdu-Kunming major transportation corridor, significantly shorten the spatial-temporal distance between the Southern Sichuan Economic Zone and the Panxi Economic Zone, effectively solve the traffic congestion problem in mountainous areas along the Jinsha River, optimize the investment environment for local cultural tourism resources and cascade hydropower stations, and boost regional economic development and rural revitalization with prominent strategic value.

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