Use instructions and later maintenance of the space frame

Space frame use instructions and later maintenance, the following three possible risks and maintenance.

Fire hazards: the temperature resistance of steel is poor, and the performance of many light steel structures varies with the temperature rise and fall, when the temperature reaches 430-540 ° C, the yield point, tensile strength and elastic modulus of steel will drop sharply, and the carrying capacity will be lost. The necessary maintenance of steel structure with refractory materials is an important lesson of steel structure research, vertical collapse in situ, forming “flat cake” effect. The direct cause of the accident, which shocked the world, was the fire. Of course, to exclude the occurrence of such events, there are also aspects involved in this case. Fire-resistant paint or sprinkler systems are ineffective.

Potential instability: ① overall instability and local instability. Most of the global instability is caused by local instability, when the slenderness ratio of the compression part or the bending part exceeds the allowable value, it will lose stability. It is affected by many objective factors, such as load changes, initial defects of steel, and different supporting conditions. Support is often ignored by designers or builders, which is also one of the reasons for the overall instability.

(2) Due to the different position of the lifting point in the lifting, the force of the rod of the truss or the space frame may change, resulting in instability; Most of the overturning, collapse or deformation of scaffolding is caused by insufficient connecting rods and no support.

Corrosion hazards: The corrosion resistance of ordinary steel is poor, especially in the environment of large humidity and aggressive media, it will rust and corrosion quickly, which weakens the bearing capacity of the components. For example, the steel roof truss in the converter workshop has an average corrosion rate of 0.10-0.16mm per year. According to statistics, 30% to 40% of the world’s annual steel production fails due to corrosion, and the net loss is about 10%. In an accident statistics of reinforced concrete roof truss, wooden house truss, steel and wooden roof truss and space frame steel roof truss, it was found that the collapse accident of steel roof truss accounted for 38.62%, and the reason of corrosion and lack of maintenance accounted for a large proportion.