L48A1 Mast Section Common causes of tower crane collapse: installation and disassembly, use, quality problems
The analysis of the reasons for the collapse of the tower crane can be divided into three aspects: one is the installation and disassembly, the other is the use, and the third is the quality of the tower crane itself.
L48A1 Mast Section：
http://www.towercranesupply.com/product/l48a1-mast-section-for-tower-crane-masts
The brief analysis is as follows:
I. causes of accidents caused by problems in installation and disassembly:
1. The installation and disassembly team has no qualification and no certificate to undertake the disassembly and assembly task. Personnel, equipment, technology and other aspects of the installation and disassembly unit do not meet the requirements, which is an important cause of the accident.
2. There is no plan for installation and disassembly, no safety technical disclosure, and experience. The direct cause of the accident is that the disassembly and assembly unit does not prepare the disassembly and assembly plan, does not conduct safety technical disclosure, and acts against rules and regulations based on experience.
3. Violation of disassembly and assembly procedures during installation and disassembly. In the process of disassembly and assembly, the disassembly and assembly unit does not follow the order of disassembly and assembly in the operation manual of tower crane, and does not operate according to the disassembly and assembly plan and safety technical disclosure requirements. The drawings are easy and imaginable.
4. Do not apply for disassembly and acceptance. The using unit and dismantling unit of tower crane do not go through the procedures of dismantling application and acceptance according to the regulations, thus losing the opportunity of checking by the competent government department.
L48A1 Mast Section：
http://www.towercranesupply.com/product/l48a1-mast-section-for-tower-crane-masts
II. Causes of accidents caused by problems in use:
1. Operators and commanders go on duty without certificates. Tower crane drivers and commanders do not receive professional training and obtain qualification certificates for work and do not have corresponding professional skills and knowledge.
2. Operators and commanders operate and command against rules. For example, overload hoisting and inclined hoisting, tower crane shall be used at the construction site to hang the concrete pump delivery pipe, lay concrete and rotate at will, etc.
3. Operators do not check and maintain the equipment daily enough, which leads to potential mechanical safety hazards of the tower crane. If the performance of the moment limiter of tower crane is not well understood, whether it really works is not clear, so that in the case of its failure, it is mistaken for its normal operation, leading to accidents. Ignore the human factors, such as in what range, can hang multiple, the heart is bottomless or unclear.
4. Insufficient education and training for operators and commanders. Many units only do pre job training, but neglect the continuous training and improvement of operators in operation skills and safety awareness, and neglect the continuous training of commanders.
III. causes of accidents caused by quality problems of tower crane products:
1 design issues. There are defects in the design of moment limiter, such as poor sensitivity, unreasonable stress in steel structure design, defects in hydraulic system design, etc.
2. Parts problems. Quality problems of moment limiter components, steel materials used in steel structure, quality problems of hydraulic system components, etc.
3 manufacturing problems
3.1 the welding of steel structure fails to meet the requirements. The height of the weld is not enough, and there are defects such as porosity, slag inclusion and even faulty welding, especially the welding quality problems in the important connecting parts of tower cap, boom and balance arm.
3.2 the geometric dimension of steel structure is inconsistent with the requirements. The blanking is not in accordance with the requirements, and the cross-sectional dimension of steel fails to meet the national standards.
4. The problem of the factory certificate and the instruction manual, without the factory certificate, is a fake and inferior product. There is no batch description and no indication of changes to the original design.
L48A1 Mast Section：
http://www.towercranesupply.com/product/l48a1-mast-section-for-tower-crane-masts
