Common causes and preventive measures of tower crane collapse accidents

1. Common causes of tower crane collapse accidents:

Analysis of the causes of tower crane collapse accidents, there are no more than three major aspects. One is the problem of disassembly and assembly. , the second is the use problem, and the third is the quality problem of the tower crane itself. A brief analysis is as follows:

1.1 The reasons for the accident caused by disassembly and assembly problems:

1.1.1 Disassembly and assembly The team has no qualifications and no license to undertake disassembly and assembly tasks. The personnel, equipment, and technology of the disassembly and assembly unit did not meet the required requirements, which was an important reason for the accident.

1.1.2 There is no plan or safety technical explanation for disassembly and assembly, just rely on experience. The disassembly and assembly unit did not prepare a disassembly and assembly plan, did not conduct safety technical briefings, and acted recklessly and illegally based on experience, which was the direct cause of the accident.

1.1.3 Violation of disassembly and assembly procedures during disassembly and assembly. During the disassembly and assembly process, the disassembly and assembly unit did not follow the order of disassembly and assembly in the tower crane instruction manual, and did not operate according to the disassembly and assembly plan and safety technical disclosure requirements, in order to save trouble and rely on imagination.

1.1.4 The disassembly and assembly application and acceptance procedures will not be handled. Tower crane users and disassembly and assembly units do not handle disassembly and assembly applications and acceptance procedures in accordance with regulations, and lose the opportunity for government authorities to check.

1.2 Causes of accidents caused by usage problems:

1.2.1 Operation and command personnel were on duty without certificates. Tower crane operators and commanders have not received professional training and obtained qualification certificates as required to work, and do not have corresponding professional skills and knowledge.

1.2.2 Operation and command personnel operate and command in violation of regulations. Such as overload lifting, inclined lifting, using a tower crane to lift the concrete pump delivery pipe at the construction site to pump concrete and rotate it at will, etc.

1.2.3 The operators did not perform enough routine inspections and maintenance of the equipment, causing mechanical safety hazards in the tower crane. If the performance of the tower crane's torque limiter is not fully understood and it is not clear whether it actually works, it may lead to misunderstanding that it is working normally and lead to an accident if it fails. Ignoring the human factors, such as to what extent and how much weight can be lifted, I have no bottom or no idea.

1.2.4 Insufficient education and training for operating and command personnel. Many units only provide pre-job training, but neglect the continuous training and improvement of operating skills and safety awareness of operators, and the continuous training of command personnel.

1.3 The reasons for the accident caused by the quality problems of the tower crane itself:

1.3.1 Design problems. There are flaws in the design of the torque limiter and poor sensitivity; unreasonable stress in the steel structure design, flaws in the design of the hydraulic system, etc.

1.3.2 Spare parts issues. Problems with the quality of the torque limiter components, problems with the steel material used in the steel structure, quality problems with the components of the hydraulic system, etc.

1.3.3 Manufacturing problems

1.3.3.1 The welding of the steel structure does not meet the requirements. The height of the weld is not enough, and there are defects such as pores, slag inclusions and even false welds. In particular, there are welding quality problems in important connection parts on the tower cap, boom, balance arm and other components.

1.3.3.2 The geometric dimensions of the steel structure do not meet the requirements. The cutting was not done as required, and the cross-sectional dimensions of the steel did not meet national standards.

1.3.4 Problems with factory certificate and instruction manual

Without factory certificate, it is a fake and shoddy product. There are no batch descriptions, and changes to the original design are not marked.

2. Preventive measures for tower crane collapse accidents;

From the analysis of the causes of tower crane collapse accidents, it can be concluded that tower crane collapse accidents are mainly due to the disassembly, use and installation of tower cranes. It is caused by its own quality problems, so measures to prevent aircraft collapse accidents are mainly proposed for these three reasons:

2.1 Strengthen the installation and disassembly management of tower cranes.

From the analysis of tower crane accidents reported in recent years, it can be seen that accidents that occur during the disassembly and assembly of tower cranes account for a large proportion of tower crane accidents. Therefore, it is also important to manage the disassembly and assembly of tower cranes well. It is the key to ensure the safety of tower crane.

2.1.1 Carefully handle the disassembly and assembly declaration procedures. Before dismantling and assembling the tower crane, the user shall declare to the relevant government authorities in accordance with regulations and provide the required declaration information. Disassembly and assembly can only be carried out after review and approval by the government authorities.

2.1.2 Select a disassembly and assembly team with corresponding qualifications.

The user unit must select a team with corresponding professional qualifications to carry out the disassembly and assembly of the tower crane, and shall not entrust a unit that has not obtained the corresponding professional disassembly and assembly qualifications to disassemble and assemble the tower crane.

2.1.3 Carefully prepare a disassembly and assembly plan and conduct safety technical briefings. Before disassembling and assembling the tower crane, the disassembly and assembly unit must prepare a detailed and feasible disassembly and assembly plan. The preparation basis, project overview, basic construction, tower crane installation, safety measures, etc. must be written into the plan and the review and approval signature must be complete. It will be implemented after approval by the entrusting unit. Before the tower crane disassembly and assembly operation, the disassembly and assembly unit should carefully conduct safety technical briefings to all construction personnel, and must go through safety technical briefing confirmation procedures.

2.1.4 Strictly follow the disassembly and assembly procedures. During the disassembly and assembly process, the disassembly and assembly procedures must be strictly followed according to the specific requirements of tower cranes of different models and specifications to prevent accidents.

2.1.5 Make good selection of disassembly and assembly equipment. Before disassembling and assembling the tower crane, the corresponding lifting equipment should be selected according to the construction site conditions, maximum structural component weight, installation height, etc.

2.1.6 Take safety protection measures at the disassembly and assembly site. Set up warning signs, set up safety slogans, and assign safety officers to be responsible for on-site safety work.

2.1.7 Handle acceptance procedures and licenses in a timely manner. After the installation of the tower crane is completed, the government authorities must be promptly requested to conduct on-site acceptance and issue a "Permit for Use".

2.1.8 Record the disassembly and assembly files. The user unit must organize and record the technical data on the disassembly and assembly of the tower crane in the equipment management files according to regulations.

2.2 Strengthen the use management of tower cranes

Usage management is an important part of equipment management and is the key to ensuring that the mechanical equipment in use is always in good technical condition and ensuring the safe operation of the equipment.

2.2.1 Establish technical files of the tower crane unit. Equipment technical files are important basic information for equipment management. They are an effective means to comprehensively record equipment operation, maintenance, repairs, oil replacement, operator changes, and major spare parts and spare parts replacement. The user should establish a technical file for each tower crane. , record the above content in time.

2.2.2 Adhere to the certificate-based employment system to ensure safe operation and command. Tower crane operators and command personnel must undergo specialized safety technical training, and can only take up their posts after passing the examination and obtaining an operation certificate. It is strictly prohibited for non-operators, non-professional commanders and unlicensed personnel to work on duty. This article is the most critical and fundamental condition for use.

2.2.3 Strengthen the management of tower crane operation records. Tower crane operators must carefully fill in the equipment operation records to ensure that the information filled in is timely, true and accurate.

2.2.4 Strengthen daily inspection and maintenance work. Tower crane operators must carefully conduct daily inspections of tower cranes in accordance with the provisions of the equipment management system. They must conduct comprehensive and detailed inspections. Key parts and important devices must be carefully and carefully inspected, and problems discovered must be dealt with in a timely manner.

2.2.5 Strictly implement the maintenance system and do a good job in the maintenance of tower cranes. It is necessary to adhere to the regular maintenance system and fixed inspection system, and insist on repairing and maintaining tower cranes according to repair and maintenance procedures, so that the equipment does not fall into disrepair.

2.2.6 Operate strictly in accordance with the parameters indicated in the tower crane instruction manual. Over-limit or overload use is strictly prohibited.

2.2.7 Earnestly implement the instructions of the state and industry and other government departments on the elimination and renewal of this type of equipment. All tower cranes that have been phased out by the state and governments at all levels must cease to be used. .

2.2.8 Frequently check whether safety devices such as tower crane torque limiters are effective.

2.3 Strengthen the procurement management of tower crane products and strictly prevent counterfeit and inferior tower cranes from entering construction companies and construction sites.

By strengthening the management of the tower crane procurement process, we will prevent low-quality equipment from entering construction companies and construction sites from the source, ensure the safety and health of employees' lives and property, and avoid adverse consequences and losses.

2.3.1 When purchasing a tower crane, you must purchase a tower crane of the corresponding model from a manufacturer with a production license issued by the competent government department.

2.3.2 When purchasing a tower crane, shop around and select the best of the best to ensure that you purchase a safe and reliable qualified tower crane.

2.3.3 When purchasing a tower crane and inspecting it upon arrival, it is necessary to check the acceptance carefully.

2.4 Strengthen education and training for tower crane operators, command and management personnel.

Education and training is an important basic work of equipment management. It is the most basic and fundamental measure to ensure the safety of tower crane use, disassembly, assembly and management. Due to the diversification of employment forms in construction enterprises under the current market economy conditions, especially the emergence of a large number of migrant workers and labor workers, their technical quality and safety skills are uneven and generally low. Therefore, the contradiction in education and training becomes even more prominent. , and more urgent.

2.4.1 Construction enterprises and their project departments must attach great importance to the education and training of tower crane operations, command and disassembly personnel, and form a system to ensure that all personnel can meet the requirements of the technical and safety management system.

2.4.2 Education and training should focus on safety regulations, relevant standards and specifications, tower crane management systems, tower crane disassembly and assembly processes, tower crane operating procedures, etc., combined with typical disassembly and assembly cases and typical accident cases , training on the use and operation of typical tower cranes.