2# Beam-making field to create good results

　　On October 18, 2017, the first box girder of the No. 2 beam-making yard of China Railway Bridge Bureau Navigational Intercity Railway was successfully poured.

　　China Railway Bridge Bureau Hanghaichengji 2# beam yard is located at DK29+000 in the center of the line. It is designed to cover an area of 160 acres and undertakes the task of making and erecting 608-hole box girder for the navigation intercity railway. The cast box girder is 35 meters in length, 10.6 meters in width, and 2 meters in height. It uses 233 cubic meters of C50 concrete, 57.8 tons of steel bars, and 9.08 tons of steel strands. The beam weighs 649.4 tons.

　　In order to ensure the smooth pouring of the first box girder, the No. 2 beam yard project department of China Railway Bridge Bureau Hanghai Intercity 2 did a lot of preparation work before construction. The first is to earnestly complete the safety technical disclosure work. The technical department compiled the relevant data and specification requirements of the box girder prefabrication into a book, and distributed it to the construction staff, and conducted intensive construction training. The second is to strengthen safety protection. In view of the safety of personnel and equipment and quality safety that may occur during the pouring process, the project department sent technicians to stick to the front line and guide and track the whole process. The successful pouring of the first piece of prefabricated box girder laid a solid foundation for the subsequent full-scale development of box girder prefabrication. (Contribution: Zhu Xiuwen) -----Excerpt from China Railway Engineering Construction Network

　　The bridge deck width of the intercity box girder is similar to that of the high-speed rail box girder, but the girder height is 2m, and the end height of the girder is only 850mm high, which is the smallest beam type in the current large box girder in the country. In the past, these ports only used wooden molds or bulk steel molds, which resulted in complicated operations and slow construction progress. But this time we designed a fully automatic integral hydraulic box girder inner mold. It overcomes more than 10 problems such as small stroke of the cylinder, interfering concrete of the mold, the design of the middle tooth block and the template as a whole and a large span, and the internal mold meets the versatility of straight curve beams and the interchangeability of various beam fields. This structure is light and simple to operate and has high construction efficiency.

　　This time, most of the intercity beams are curved beams, with many radius of curvatures, and complicated changes in beam width and beam length. The versatility and interchangeability of the formwork are all considered when designing. The outer mold baffle mold adopts a structure that can advance and retreat to meet the requirements of the beam flange. Radii of curvature. The end mold is designed as a bracing structure, which realizes a variety of rotation angles, and at the same time satisfies no slurry leakage during beam driving.

　　The template structure design is light and exquisite, while meeting the strength and rigidity of the beam, and the operation is simple. In order to ensure smooth demolding, the template is divided into multiple sections at the deflection position, and the hinged ear plate is a special structure. This time the box girder design has applied for a number of patents, and the technology has broken the unprecedented difficulty. The Dongfeng R&D team worked together to discuss for the first time the automatic hydraulic closing of the large box girder with the smallest port in China. It has made outstanding contributions to the successful pouring of the first beam for the bridge construction of the navigation intercity railway project.