Core Viewpoint - The construction of the Chengyu Central Line High-Speed Railway, particularly the Jianyang Tuojiang Grand Bridge, is a significant engineering project that utilizes an innovative thrust-free arch bridge design to enhance efficiency and reduce construction costs while meeting navigational requirements [1][3][4]. Design and Engineering Challenges - The design of the thrust-free arch bridge was chosen due to the poor load-bearing capacity of the mudstone and sandstone geological conditions along the Tuojiang River, which made conventional thrust bridges unsuitable [3][4]. - The design team faced a critical decision between a thrust-free arch bridge and a cable-stayed bridge, ultimately opting for the former due to its lower excavation volume, shorter construction period, and reduced costs despite less design experience [4]. Digital Modeling and Construction Techniques - The project employs Building Information Modeling (BIM) and virtual assembly technology to enhance the efficiency of assembling the arch ribs, which are composed of multiple steel pipes filled with concrete [5][6][8]. - The construction team utilizes a smart monitoring system based on BIM to ensure precise lifting and assembly of the 2,400-ton steel arch segments, achieving millimeter-level accuracy in height control during the lifting process [9]. Quality Control Measures - The bridge incorporates approximately 72,000 high-strength bolts, with an intelligent tightening system ensuring each bolt is tightened to the correct torque, thus preventing issues such as under-tightening or over-tightening [10][11]. - An intelligent temperature control system is implemented to monitor and adjust the cooling of concrete during pouring, mitigating the risk of cracking due to temperature differentials [12]. Project Timeline and Future Outlook - The Jianyang Tuojiang Grand Bridge is expected to be completed in the second half of this year, with the first high-speed train anticipated to traverse the bridge shortly after its completion [12].

Core Viewpoint - The construction of the Jianyang Tuojiang Grand Bridge is a key project in the Chengdu-Chongqing high-speed railway, which will significantly reduce travel time between Chengdu and Chongqing to 50 minutes upon completion [7][8]. Design and Engineering - The bridge features a main arch span of 320 meters and side arches of 72 meters, designed as a thrust-free composite arch bridge to accommodate geological conditions and navigation needs [8][9]. - The design process began in 2020, with the team opting for a thrust-free composite arch bridge over a cable-stayed bridge due to lower excavation volume, shorter construction time, and reduced costs [10][11]. Construction Techniques - The construction employs Building Information Modeling (BIM) and virtual assembly technology to enhance the efficiency of assembling the massive arch components [11][14]. - Each arch rib is composed of four steel pipes filled with concrete, with a length of 12 meters per rib, and the construction team utilizes digital scanning to ensure precision in assembly [11][12]. Quality Control - The project incorporates an intelligent bolt tightening system to ensure the correct torque is applied to approximately 72,000 high-strength bolts, preventing issues such as under-tightening or over-tightening [17][18]. - An intelligent temperature control system is also implemented to monitor and adjust the cooling of concrete during pouring, mitigating the risk of cracking due to temperature differentials [19]. Project Timeline - The Jianyang Tuojiang Grand Bridge is expected to be completed and ready for the first high-speed train service by the second half of this year [19].