A Novel Conceptual Telescopic Positioning Pile for VLFS Deployed in Shallow Water: Structure Design

Abstract

A conceptual design of using novel telescopic piles to position a multi-modular very large floating structure (VLFS), which is supposed to be severed as a movable floating airport, is proposed. The telescopic piles can automatically plug in the soil to resist the environmental loads and pull out from the soil to evacuate or move on to the next operational sea. The feasibility demonstration of the conceptual design includes two parts: function verification and structure design. In the latter part of the conceptual design, a time-domain structural analysis is firstly conducted by using Abaqus software. The simulation results suggest that the preliminary structure scheme is not optimum due to the insufficient structure utilization, although both structure safety of the piles and positioning accuracy are guaranteed. To realize a cost reduction of construction and installation, a Genetic Algorithm-Finite Element Analysis (GA-FEA) method is employed to perform structural optimization. After optimization, 31 percent of the weight of each pile is reduced and higher structure utilization is maintained. The difference of the self-weight and allowable buoyancy of a single module (SMOD) of a semisubmersible-type VLFS is much larger than the weight of the piles. Combined with the function verification in our previous work, the conceptual design of using the novel telescopic pile to position VLFS is demonstrated to be feasible.