② The lifting and lowering shall be carried out during the day.
2.
Many units have only achieved pre job training, ignoring the continuous training and improvement of operators in operation skills and safety awareness, and ignoring the continuous training of commanders.
3.
When lifting the tower body of the tower crane, the following requirements shall be met: ① during the lifting operation, special personnel must be assigned to command, take care of the power supply, operate the hydraulic system and disassemble the bolts.
Operators and commanders operate and command against rules.
The disassembly and assembly unit did not prepare the disassembly and assembly plan, did not carry out safety technical disclosure, and acted recklessly in violation of rules and regulations based on experience, which was the direct cause of the accident.
3.
The tower crane driver and commander did not receive professional training and obtain qualification certificate as required, and did not have corresponding professional skills and knowledge.
There is no batch description, and the changes to the original design are not indicated.
When it is necessary to work at night under special circumstances, there shall be sufficient lighting.
Safety precautions for tower crane operation 1.
➤ the geometric dimension of the steel structure does not meet the requirements.
There is no scheme for installation and disassembly and no safety technical disclosure, based on experience.
The design of torque limiter has defects and poor sensitivity; Unreasonable stress of steel structure design, design defects of hydraulic system, etc.
All safety devices on the tower crane shall be kept sensitive and effective.
What caused the tower crane to collapse? From a large perspective, there are no more than these three ↓↓↓.
Manufacturing problems ➤ steel structure welding fails to meet the requirements.
At present, one of the injured has been transferred to the hospital for treatment, and his life is not in danger.
After the accident, the main leaders of the Party Working Committee and Management Committee of Gedian Development Zone rushed to the scene at the first time to organize relevant departments such as housing construction, public security, emergency, fire control, medical treatment and project construction units to carry out emergency rescue.
2.
Spare parts.
The demolition of tower crane must be carried out by a professional team with demolition qualification certificate issued by the competent construction administrative department, and shall be supervised by technical and safety personnel on site.
2.
3.
For example, overload hoisting, inclined hoisting, hanging the concrete pump delivery pipe with a tower crane at the construction site, beating concrete and rotating at will, etc.
Insufficient education and training for operators and commanders.
The personnel, equipment and technology of the installation and disassembly unit do not meet the requirements, which is an important cause of the accident.
4.
Only one person is allowed to operate in the control room, and the command signal must be obeyed.
First, the installation and disassembly of tower crane; Second, the use of the problem; The third is the quality problem of the tower crane itself.
⑤ During lifting, the clearance between the lifting jacket roller and the standard section of the tower body must be adjusted, the boom and balance arm shall be balanced according to the regulations, and the slewing mechanism shall be braked, When it is difficult to disassemble the last connecting bolt (PIN) between the return turntable and the standard joint of the tower body, re insert the diagonal universal bolt and take other measures.
⑦ after lifting, all connecting bolts shall be tightened according to the specified torque, the hydraulic control rod shall return to the middle position, and the power supply of the hydraulic lifting mechanism shall be cut off.
The use unit and disassembly unit of the tower crane did not handle the disassembly application and acceptance procedures according to the regulations, and lost the opportunity to be checked by the competent government department.
The operator’s daily inspection and maintenance of the equipment are not enough, resulting in potential mechanical safety hazards of the tower crane.
The height of the weld is not enough, and there are defects such as pores, slag inclusion and even false welding.
Gedian Development Zone has set up a special work class to do a good job in the aftermath.
After being approved by the technical director of the enterprise, they shall be used as the technical scheme for removal operation, and disclosed to all operators.
In the process of disassembly and assembly, the disassembly and assembly unit does not carry out disassembly and assembly according to the sequence of disassembly and assembly in the tower crane operation manual, and does not operate according to the disassembly and assembly scheme and the requirements of safety technical disclosure.
Ignoring human factors, such as what range and how much can be suspended, and having no bottom or unclear in mind.
When the wind force suddenly increases to level IV during operation, it must be stopped immediately, and the connecting bolts of the upper and lower tower bodies shall be tightened.
③ When the wind force is above level 4, lifting operation shall not be carried out.
Non operators are not allowed to board the operation platform of the jacking jacket.
④ Before lifting, loosen the cable in advance, its length should be greater than the total height of jacking, and fasten the cable drum.
Quality problem of moment limiter element and material problem of steel used for steel structure; Quality problems of hydraulic system components, etc.
In particular, there are welding quality problems at important connecting parts on tower cap, boom, balance arm and other components.
How dangerous is the moment when the tower crane collapses? If the camera hadn’t recorded the moment of the incident, maybe you couldn’t believe it ↓↓↓ tower crane accidents caused by improper operation are common.
Do not loosen the bolt (PIN) by rotating the jib.
4.
In December 8th, the official WeChat official account of the state level Gedian economic and Technological Development Zone announced that at 12:15 noon on December 8, 2021, a tower crane crashed in the Huarun block of Gedian development zone.
4.
If any failed safety device is found, it shall be repaired or replaced in time..
4.
Tighten the cable in time when descending.
Causes of accidents caused by problems in installation and disassembly 1 The installation and disassembly team is unqualified and undertakes disassembly and assembly tasks without certificate.
Before the removal of tower crane, the disassembly operation methods, quality requirements and safety technical measures shall be prepared in accordance with the relevant factory regulations.
The accident resulted in three deaths and one injury.
⑥ when lifting, jack up the support foot (climbing claw) after being in place, the safety pin shall be inserted before continuing the next action.
The cause of the accident needs further investigation.
It is easy to figure and imagination.
The problem of factory certificate and operation manual, without factory certificate, is a fake and shoddy product.
3.
2.
If the performance of the tower crane moment limiter is not understood enough, and it is not clear whether it really works, the accident will be caused by mistaking it for normal operation in the case of its failure.
Violation of disassembly and assembly procedures during installation and disassembly.
The blanking is not in accordance with the requirements, and the steel section size cannot meet the provisions of the national standard.
Do not handle the disassembly application and acceptance procedures.
Causes of accidents caused by quality problems of tower crane products 1 Design issues.
Causes of accidents caused by problems in use 1 Operators and commanders work without certificates.