Analysis of the hottest tower crane accident case

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Case analysis of tower crane accident: the overloaded lifting tower overturned and collapsed the roof, injuring people

the driver of a t tower crane in a workshop of a factory is in charge of lifting and unloading more than 100 tons of steel from nine trucks pulled by the transportation company. When unloading from the truck, the rigger of the transportation company is responsible for threading the wire rope sling hook. The first truck was unloaded by lifting three times, but from the second truck, in order to speed up the progress, it was unloaded by lifting twice. Qiao, the consignee on the scene, once warned that the truck could only lift 31 at a time and should be lifted less. However, the rigger of the transportation company refused on the ground that the signs of the car were t at the same time, and continued to hang and unload two cars by lifting each car twice. When it was hoisted to the second hook of the fourth truck, when the jib rotated from south to west and North after lifting, it happened to encounter a strong wind, and the company hoped to add graphene nano materials, causing the tower crane to overturn. Make the crane with a weight of dozens of tons fall on the roof of the reinforcement workshop, and the clamping force will increase with it, which will collapse. At that time, more than 20 people were working in the workshop. Pu, an electric welder, was crushed to death on the spot, and many people were injured

accident cause analysis:

(1) the lifting torque limiter of the vehicle failed to repair, and the warning signal could not be sent in time before overload overturning, resulting in the loss of protection function

(2) there is neither lifting characteristic table nor lifting performance indicator in the cab, and the driver cannot master the crane at different amplitudes 11 Unit: kg, LB, N, kn, its corresponding rated load value, so as to produce the possibility of overload overturning

(3) when the crane overturns, the amplitude is 16.3m, and its corresponding rated load is 2.74t. At this time, it lifts 6.45t, which is already in danger of overturning. In addition, the strong wind blows, which greatly weakens the stability torque, and the overturning torque increases sharply due to overload, which will inevitably lead to the overturning of the crane

(4) after overhaul, the crane was put into operation without safety inspection and acceptance

(5) there is no special person to command the lifting operation, and the operation is against rules

(6) the driver took charge of someone who was not trained to obtain a certificate, which was an unlicensed illegal operation

accident lessons and preventive measures:

(1) illegal operations without certificates are strictly prohibited, and all special types of work must be trained and certified

(2) the jib crane must be equipped with limit moment limiter and lifting performance indicator, so as to have operation basis

(3) overload lifting is strictly prohibited

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