Technical Study on Four-Crane Joint Lifting of Large-Sized Structures

In recent years, due to rapid development of offshore engineering construction, offshore structure size and weight becomes larger and larger. In the process of offshore structures fabrication, the size and weight of the sub-structure is also becoming bigger, lifting method using single or two sets of cranes cannot meet the capacity requirement of the lifting operation, joint operation using four cranes is required in such cases. To solve this problem, this paper analyze the riskfactors(the uncertainty of the hook load, the inaccuracy of the center-of-gravity, limited working condition ) in the process of joint liftingusingfour crane.The paper also discusses the whole lifting process and simulates the process by usinganalysissoftware SACS, and the calculation result matches actual work very well.