Prestressed concrete box girder bridges utilize prestressed concrete as the primary structural material. Their cross-sections typically feature box shapes, including single-cell single-chamber, single-cell multi-chamber, and other forms. The characteristics of this bridge structure lie in its strong flexural capacity, high modulus of elasticity, and good seismic performance, resulting in excellent structural behavior and stability. In prestressed box girders, prestressing steel tendons are tensioned and anchored within the concrete to create a state of prestress, thereby enhancing the bridge's load-bearing capacity. The girder body can employ cast-in-place concrete or prestressed concrete structures, which helps improve seismic performance and reduce the bridge's self-weight. Prestressed box girder bridges offer advantages such as convenient construction, short construction periods, and low maintenance costs, leading to their widespread application globally. They are particularly favored for long-span bridges due to their aesthetically pleasing shape and excellent structural performance. In summary, the prestressed concrete box girder bridge is a structural form with outstanding performance and broad application prospects. This article provides an overview of the preparatory work involved in the short-line match casting method for segmental girders of prestressed box girder bridges.

1. Site Layout and Equipment Preparation

During the preparatory phase for short-line match casting of segmental girders, the layout of the construction site is a crucial first step. This is not merely a simple matter of spatial planning but requires comprehensive consideration of multiple factors such as topography, traffic conditions, and construction sequences. The site layout must clearly demarcate key areas including the segment precasting yard, storage area, transportation routes, and lifting zones to ensure a smooth construction workflow. Considering construction efficiency and safety, the precasting yard needs to be equipped with adequate drainage systems and protective measures to prevent construction delays or safety incidents caused by weather or human factors. Regarding equipment preparation, in addition to conventional reinforcement processing machinery, concrete batching, and conveying equipment, particular attention must be paid to the preparation of the segment casting beds and the formwork system. This equipment must not only be highly precise and stable but also adaptable to varying construction requirements, ensuring the quality and efficiency of segment production.

2. Drawing Review and Material Preparation

The review of construction drawings is one of the core tasks in the preparatory stage. The accuracy and completeness of the drawings directly impact construction quality and progress. Before commencement, a detailed review by qualified personnel is essential to ensure all information in the drawings is accurate. Concurrently, corresponding construction materials must be procured based on the drawing specifications. These materials include reinforcing steel, prestressing tendons, concrete raw materials, and formwork materials. During material preparation, ensuring material quality complies with design requirements is paramount, along with addressing issues related to transportation and storage. Particularly for materials susceptible to moisture or deformation, appropriate protective measures are necessary to maintain their optimal performance during use.

3. Workforce Organization and Training

The organization and training of the construction workforce represent another critical task in the preparatory phase. A skilled and experienced team is vital for ensuring construction quality and safety. Prior to starting work, a professional construction team must be assembled, with rational task allocation and scheduling based on project scope and timeline requirements. Furthermore, to enhance the overall competency and skill level of the workforce, comprehensive technical training for personnel is required. Training content should encompass not only the study and understanding of construction drawings, mastery of construction techniques, and technical specifications but also include safety education and the development of emergency response capabilities. Through training, personnel should gain a thorough understanding of project objectives, master correct construction methods and techniques, and improve construction quality and efficiency. Additionally, a detailed construction plan and emergency response must be developed to address potential unforeseen situations, ensuring the smooth progression of the construction process.

Conclusion

In summary, the preparatory work for the short-line match casting of segmental girders in prestressed box girder bridges is a systematic project encompassing multiple critical aspects such as site planning, equipment configuration, technical review, material assurance, and workforce organization.

Thorough and meticulous preparatory work forms the foundation for the smooth execution of subsequent construction activities and is a key prerequisite for ensuring project quality, safety, and cost-effectiveness. Only by conducting these preparations deeply, meticulously, and solidly can favorable conditions be created for the full deployment of the short-line match casting process, thereby enhancing the overall comprehensive benefits of the bridge construction project.

In the next article, we will detail the construction sequence and key technical points for the short-line match casting of segmental girders in prestressed concrete box girder bridges.