Necessary conditions and reliability indexes for l

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Conditions required for crane load test and precautions for reliability index evaluation

load test is an important comprehensive index for inspecting the product quality and safety performance of lifting machinery. Through load test, it can not only detect the deformation of crane metal structure, such as the deflection value of bridge crane, but also detect the effectiveness of crane safety devices, such as overload limiter, Action protection of moment limiter of tower crane under rated load, etc. In a word, the load test is extremely important to check the structural bearing capacity of the crane and its components, the crane's welding, crack, permanent deformation, loose connection, the effectiveness of the safety device and the damage affecting the crane's performance and safety

1. if several important conditions for load test are not met, it is very easy to cause accidents

(1) cranes whose product quality has not been demonstrated, especially cranes whose main stress-bearing parts have not been inspected and have no quality certificate

(2 (2) nano carbon materials) installation has not been completed, and the person in charge of the installation unit has not identified the handed over crane

(3) crane with incomplete safety devices and no function

(the project focuses on the research, development and implementation of new renewable raw materials 4) the oil level at the lubricating part is insufficient, which is prone to gear wear and damage. The failure should be correctly selected according to the regulations, resulting in accidents

(5) the connecting bolts of the main stressed parts are not fastened, and the fixing of the end of the steel wire rope does not meet the requirements

2. the load test procedure cannot be reversed, the safety judgment must be accurate, and the reliability index should be evaluated

(1) the load test shall be carried out on the basis of the "floating paradise" caused by the relevant safety measures falling on 150000 plastic bottles, and according to the procedures of no-load test, rated load test, static load test and dynamic load test

(2) no load test: check the operation of each mechanism under no-load condition, and check the accuracy and stability of each mechanism during operation. After the no-load test is qualified, the rated load test can be carried out

(3) the rated load test must be carried out at the specified position. For example, the tower crane shall lift the maximum rated lifting capacity and the maximum rated lifting capacity respectively at the corresponding range. When evaluating the rated load of the crane, the maximum stress of the structure shall be taken as the safety judgment basis according to the type of dangerous stress zone

(4) after the static load test, all parts of the crane shall not have any problems that affect the service performance and safety quality, such as broken connections and looseness. The dynamic load test can be carried out only after the static load test

(5) after all tests of the tower crane are completed, the reliability index shall be allowed for the appraisal of the crane

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