Abstract:Taking the incremental launching construction of the 212-meter-long, 35.5-meter-wide, self-weight 25 000-ton curved concrete box girder of the main bridge of the Shangdi Railway Grade-Separated Interchange on the Jingba Expressway (a long-span single-pylon single-cable-plane prestressed concrete curved cable-stayed bridge) as the engineering background, this paper systematically investigates the key technologies for long-distance, single-point curved incremental launching construction of complex-shaped, large-tonnage, wide concrete box girders. The paper elaborates on the specialized structural design measures for curved girder launching, the launching trajectory and deviation correction control system based on the two-point limiting principle, the high-performance MGE slider-skidway system, the large-tonnage continuous traction system, and the entire-process dynamic monitoring system based on Fiber Bragg Grating (FBG) technology. Through comparative analysis of theoretical calculations (MIDAS Civil/FEA finite element simulation), test segment validation, and measured data from the entire construction process, the feasibility, safety, and accuracy of the construction design scheme are verified. Key technical challenges encountered during construction and corresponding countermeasures are summarized. The successful implementation of this project provides valuable design and construction experience for the incremental launching construction of long-span, complex-shaped concrete bridges in China.
