The lifting device consists of three parts: the main lifting beam, cross braces, and lifting ears. The main lifting beam of the 8-point lifting device is a steel box steel structure, and the cross braces are a steel pipe structure. The main lifting beam, cross brace, and lifting lug are connected as a whole with pins.
The main lifting beam is divided into three sections, with fixed ends at both ends and an adjustment section in the middle. It is connected with high-strength bolts and can be combined in various ways to meet the lifting requirements of different length beam sections, thus achieving universality.
Assuming the following, conduct a force analysis on the layout of planar strut hangers and cross slings:
1. The asynchrony of the hook. Assuming that during the lifting process, the asynchronous height difference between the two hooks of the floating crane is not greater than 80mm.
2. Difference in the length of slings: Based on the possible accuracy achieved by factory manufacturing, it is assumed that the relative manufacturing error in the length of all slings (including the main and secondary slings) is 50mm.
3. Through force analysis, it can be seen that the unsynchronization of the floating crane hook and the difference in cable length have a significant impact on the stress of the 8-point lifting tool structure. Therefore, during construction, strict control must be exercised over the use of 8-point lifting appliances and the production of their cable lengths.