The MIRROR concert had a stage accident earlier, when a large screen fell and hit the dancers.
After the incident, an inter-departmental task force led by the Leisure and Cultural Services Department pointed out that after examining the fracture of the broken wire rope, it found that there were signs of metal fatigue causing the wire to break, and the police also seized a broken screw.
However, Zhang Niansheng, managing director of KONE Elevator, who often deals with wire rope problems, pointed out that there are different possibilities for the cause of this accident, and the final result will have to wait for the report of the government's inter-departmental task force.
But he estimates that there are two more likely reasons, including that the steel cable had hit a foreign object when it was raised, or the screw was over-tightened during installation, causing it to break.
▼The giant screen of the MIRROR concert fell on the evening of July 28▼
Zhang Niansheng, managing director and engineer of KONE Elevator, pointed out that metal fatigue is only a "general term" in the industry.
According to the characteristics of metal, there is a certain degree of softness. When the pressure at a certain point is too strong, it may cause cracking or breaking, which is generally called metal fatigue.
Zhang Niansheng said that according to its characteristics, the metal will not have problems immediately. Before it breaks, the steel cable will be slowly stretched. Maintenance personnel will regularly measure the length of the wire rope, and if it is a few millimeters longer, the wire rope needs to be replaced.
He said that metal fatigue is very common, but it is generally difficult for the public to detect it with the naked eye.
▼The live high-definition picture restores the MIRROR concert "The Disappearing Ring"▼
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Possibility 1: The steel cable is close to brand new and has a chance to collide with foreign objects
Zhang Niansheng estimated that the accident involved a number of possibilities, which may involve steel cables. When the screen rose, it might have hit a foreign object, which would increase the weight of the steel cables and eventually cause them to break.
He explained that it is still unclear whether the steel cable has been collided, but according to the scene clips, the steel cable swayed left and right when it rose. "If the metal is fatigued, it is very possible."
Zhang Zhi, referring to the photos, the steel cables in this concert are relatively smooth, with no signs of dilapidation or raw embroidery, so the chance of accidents should be low. "I believe (steel cables) are not brand new, they are close to brand new." Materials, and the concert was only held for 3 days before the accident. He described the situation as very rare, so he tended to believe it was an external factor.
He also mentioned that the screen will move during this performance, and it is not safe to use only two steel cables. The three- to four-point hoisting position is used, so it may be a design problem. "If such a heavy object is unstable and It's tight, it shouldn't be tied down below." He also estimated that if the original design did not include movement, but forced movement during operation may also lead to accidents.
▼The police seized a broken screw suspected of being related to the case▼
Possibility 2: The screw is too tight
In addition to involving steel cables, screws may also be one of the more likely causes.
Zhang Niansheng pointed out that the load-bearing screws should not be twisted too hard, otherwise the inside of the screw may be cracked, so it is unable to carry the load. This phenomenon is also one of metal fatigue.
Zhang said that when twisting the load-bearing screw, there will be a special tool to ensure the tightness, and then the Shibo will use the tool to twist it, but after the force is too strong, it can no longer be twisted.
Zhang estimates that the worker may not have used the proper tools, such as using only a wrench to install, or the inside of the screw was broken before installation.
He also pointed out that under normal circumstances, workers should be checked by a supervisor before using any tools.
After the inspection, the tool will be recorded, and then handed over to the engineer for safekeeping. When the specification is confirmed to be correct, the engineer will conduct independent inspection and random inspection.
He suspected that there might be a problem during the installation process, "Did (the supervisor) do it? Or is it necessary to fill it up? No one knows."
MIRROR concert︱Afeng IG issued a message to hope that Qi people will come to the stage again. It is said that he has been discharged from the hospital to recuperate. The police ward discussed Tianyu's tragic change to a vegetative father, citing netizens' letters and shouting the government's cold treatment: MIRROR attaches great importance to the MIRROR concert | The task force examines the broken screen of the wire rope or the metal fatigue of the wire rope