After the space frame structure is treated with anti-corrosion and fire prevention, the corrosion resistance and fire resistance can be greatly improved. However, in the actual construction of the project, due to improper selection of paint and fireproof coatings, and inadequate control of the surface temperature of the steel components and the environmental temperature and humidity during construction, the quality of the project was severely affected.

Principles of anti-corrosion and fire protection of grid structure

The principle of steel corrosion is mainly electrochemical corrosion. The base material of space frame, welding slag and stress caused by welding will form the cathode and anode areas of the corrosion battery, especially when the steel surface is not completely rusted. There will be a layer of rolled oxide scale on the surface.

The corrosion of the space frame structure in the atmosphere is mainly oxygen absorption corrosion. The fire protection of the space frame structure mainly uses the fire protection and heat insulation principle of the fire protection coating, and uses the low thermal conductivity, heat insulation and oxygen isolation characteristics of the material constituting the coating to protect the steel components and prevent heat radiation.

Several reasons that affect the "diseases" of the space frame structure:

1. During the construction in the rainy season, to meet tight construction deadline, the fire retardant coating is not fully dried while the next process is carried out, which makes the moisture content of the fire retardant paint beyond the standard, and the adhesion with the intermediate paint and top paint cannot reach product and design requirements, the phenomenon of hollowing and paint peeling occurred in the later stage.

2. If there is a lot of rain in the area of the space frame structure project, the rainwater is more acidic. After the roof is aging and damaged, acid rain erosion and solar rain will aggravate the problems of the surface paint and fireproof paint of the space frame structure, hollowing and paint stripping.

3. Insufficient attention is paid to maintenance during the period of use, and effective measures are not studied and taken to prevent large-area hollowing and falling off of topcoat and fire-resistant paint during the initial stage of hollowing and paint stripping of the space frame structure.