The formwork requirements for the construction of fair-faced concrete precast components are very strict.

1. Concrete mix ratio design and quality control of raw material fair-faced concrete protective agent. The cement mix ratio used in each piece of concrete must be strictly consistent; fresh concrete must have excellent workability and cohesion, and delamination and segregation are absolutely not allowed. The origin of raw materials must be consistent, and the cement used should be from the same batch of precast concrete component manufacturers as much as possible; the color and particle gradation of sand and stone should be uniform.

　2. Template project.

The formwork requirements for the construction of fair-faced concrete prefabricated components are very strict and need to be designed and customized according to the building. Most of the formwork used is disposable and the cost is high. It is best to use exit formwork for important parts such as corners, beam and column joints.

The formwork must have sufficient stiffness, and no deformation is allowed under the lateral pressure of the concrete, to ensure uniform geometric dimensions and consistent cross-sections of the structure, and to prevent slurry from being lost; there are also very high requirements for the materials of the formwork, which must have a flat and bright surface, high strength, corrosion resistance, and a certain degree of water absorption; for the joints of the formwork and the bolts that fix the formwork, the joints are required to be tight, and sealing strips must be added to prevent slurry from running. It is a type of bridge beam with a hollow interior and flanges on both sides of the upper part, resembling a box, hence its name. Divided into single boxes, multiple boxes, etc.

Box girders of reinforced precast concrete components are divided into precast box girders and cast-in-place box girders. Box girders prefabricated at an independent site combined with a bridge erecting machine can be erected after the lower part of the project is completed, which can speed up the project progress and save construction period; cast-in-place box girders are mostly used for large continuous bridges. At present, there are two main types of materials: one is prestressed reinforced concrete box girder, and the other is steel box girder. Among them, prestressed reinforced concrete box girders are constructed on-site. In addition to longitudinal prestressing, some also have transverse prestressing. Steel box girders are generally processed in the factory and then transported to the site for installation. There are all-steel structures, and some have reinforced concrete paving layers.

Steel box girder, also called steel plate box girder, is a commonly used structural form for long-span bridges. Generally used on bridges with larger spans. It looks like a box, so it is called a steel box beam.

Steel plate box beams are a structural form commonly used in engineering. In order to study the effect of diaphragm spacing on the distortion of simply supported steel box beams under concentrated loads, simply supported steel box girders with different numbers of diaphragms were set up to compare their distortion effects and rigid torsion effects under concentrated loads, and the maximum The variation curve of distortion effect with the number of diaphragms·A concentrated load is applied to the top of the box girder web, and the load decomposition method is used to calculate the four working conditions of distortion, rigid torsion, symmetrical bending and eccentric load·