Automated rigging design for heavy industrial lifts

Abstract

Modular-based heavy industrial construction projects typically involve the use of mobile cranes to lift and place large heavy prefabricated modules. These modules must be lifted vertically, raised evenly, and maintained in a level position during the lift in order to prevent them from deflecting and, more importantly, to mitigate safety issues regarding potential rigging failure. In this respect, a comprehensive crane lift study at the planning stage of the project is required to ensure the lifts are successful and to improve safety and productivity. One of the most tedious and time-intensive tasks involved in conducting the lift study is the design of the rigging assemblies, which are the link between the crane hook and the module. In practice, however, this task is performed manually and relies heavily on guesswork, which is error-prone and time-consuming, especially when the center of gravity is offset from the center of the module. Poorly designed rigging assemblies are only detected at the job site when the module does not raise evenly at the beginning of the lift, which then results in wasted time and productivity loss as the assembled components have to be unrigged and properly adjusted. To overcome these limitations, this paper proposes an automated mathematical-based rigging assembly design system that consists of: (i) collecting module and available rigging component information; (ii) the solver analysis, which calculates the sling angles and performs the calculations required to balance the module; (iii) the rigging assembly designer, which determines the required capacity of the rigging components and selects the suitable riggings from the database; (iv) rigging assembly design alternatives; and (v) the 3D visualizer, which creates a 3D model of the designed rigging assembly. This framework enables lift engineers to create rigging assembly designs more precisely and expeditiously. The methodology is validated in a case study.