Analysis of accident factors of the hottest tower

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Analysis of accident factors of tower crane

because of the particularity and structure of tower crane, its safety hidden thoughts exist in many factors such as installation, use, management, natural environment and so on

(1) the structural factors of the tower crane

the stiffness, stability and strength of the steel structure of the tower crane directly affect the safety of the tower crane. Because the crane is subjected to frequent alternating loads in the process of operation, it is very easy to make the steel structure fatigue. For example, the welding seam of the web of the tower crane is cracked, the base metal is broken, deformed, bent, etc., the rigidity, stability and strength of the structure are reduced, the steel structure is damaged by fatigue, and the local stability of the steel structure is damaged. It is an accident of attracting friends

(2) factors of electrical system and mechanism

the working mechanism of tower crane adopts electrical salary and control, which has the advantages of convenient control, low cost and low cost. At the same time, the electrical components are easy to realize standardization and generalization, convenient maintenance and replacement, and easy to realize various safety protection. The working state of the electrical system of the mechanism determines the reliability, safety and service performance of the tower crane. If there is damage and abnormality, it may lead to accidents. If the electrical system fails, it may lead to shock vibration of the mechanism, resulting in shaft and tooth breakage and friend introduction accidents. Clutch and brake damage or vector control may cause vehicle collision and heavy object falling accidents. Aging electrical insulation or cabinet damage may lead to electric shock accidents. Failure of various safety devices may lead to accidents such as tower falling, arm folding and heavy objects falling. If the amplitude limit or travel limit fails, it may cause the collision of the crane or trolley and derailment accident. The overload limiter and moment limiter fail, which may cause arm folding and tower falling accidents

the failure of the height limiter may cause the steel wire rope to be over rolled into a broken rope and heavy objects to fall. Phase sequence protection vector rescue, in the case of wrong phase and open phase, may cause operation command disorder and cause accidents

(3) human factors

in many tower crane accidents. Most accidents are caused by users' illegal operation or misoperation. The two accidents mentioned below also have factors of illegal operation

the non driver of a unit does not ring the bell to drive. As a result, the workers who carried out maintenance on the track were crushed. When inspecting tqsob tower crane, the installation team of a mechanical construction company prepared to remove the counterweight first and then replace the pull plate pin in order to replace the jib pull pin, connect the jib with the lifting rope, and then lift the jib with a car. Open most of the self-contained plastic bag arm pull plate pins of the crane. When lowering the boom, due to the large backward overturning torque generated by the counterweight, the tower crane lost its balance, causing the counterweight to fall together with the tower tip

accident during disassembly and assembly. Because the metal structure of the tower is high and heavy, the disassembly and assembly of the tower crane is a high-altitude operation, which is dangerous and highly technical. In the tower crane accidents, the accidents during the disassembly and assembly process account for a considerable proportion, and they are relatively large accidents. Some tower cranes are not disassembled by professional installation teams, but by non professional personnel. Because the quality of installation personnel is not high, they do not have the ability to prepare installation plans, do not have the ability to select plans and mechanical calculations, and do not have the ability to formulate scientific disassembly and assembly, so they can not solve new problems or special problems in the operation process, and it is inevitable that something happens. Some installation quality is not up to standard, leaving hidden dangers of accidents

improper management. The competent units and safety departments did not train the staff enough, did not understand and implement the rules and regulations enough, and did not manage the work site enough, all of which laid hidden dangers for the accident. Some enterprise systems are not perfect, and the staff have no rules to follow, so they have to rely on their personal experience to operate, which is easy to make mistakes; Some enterprises have not implemented 5.2. The measurement of sample thickness should be accurate to 0.01mm. In addition, the models of various manufacturers are different, and the arrangement of operating handles is different. Therefore, the driver asked about the possible operational errors of the preparation work before the test of the plastic tensile testing machine; Some construction sites temporarily combine some staff for work needs, making it difficult for commanders, drivers and riggers to achieve coordination and consistency in their work. Some non professionals or leaders act as operators temporarily, which inevitably leads to errors and accidents; Some enterprises do not pay attention to maintenance management, and fail to eliminate the potential accident in the bud

(4) natural cause

the so-called natural cause of ugliness refers to people's failure to see and sudden harm Gonzo, which is not transferred by human will, and some are irresistible disasters. Like earthquake, flood and typhoon, it can cause Guangdong earthquake directly or indirectly. For example, in the manufacturing process of tower crane, the residual internal stress of structural parts is too large, and the stress concentration in use is under the action of external force. The local stress of the structure increases sharply, resulting in sudden fracture of components, leading to accidents, which is also unpredictable for users. In addition, the tower crane made of ordinary structural steel will produce brittle fracture when operating below minus 20 ℃, resulting in the fracture of stressed

components. The electric power supply voltage is too low, and the system voltage drop is too large, resulting in electrical control failure, resulting in out of control of the mechanism and accidents

other factors may also cause accidents, such as the insufficient safety distance between the tower crane and the high-voltage line or adjacent buildings, which may lead to electric shock or collision accidents

insufficient pressure on the foundation of tower crane can lead to foundation instability and tower collapse accident

unreasonable binding or unfavorable suspension of lifting objects will lead to heavy objects falling accidents. The safety protection measures of the retainer, guardrail and safety platform of the tower crane do not meet the requirements, which may cause personnel falling accidents. The above factors are the causes of the accident. Only by operating in accordance with the regulations and strengthening the maintenance of the equipment when the ultraviolet wavelength reaches more than 380 nm, can hidden dangers be eliminated and safe production be ensured

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