Feasibility assessment for design of a circular one-cell concrete submerged floating tunnel structure

Abstract

The selection of an initial section is one of the most important issues in the design of a submerged floating tunnel (SFT) structure, because selection of a proper initial section can minimize the number of iterations needed to reach a final section design. Based on the introduction of a three-dimensional (3-D) equivalent static approach, the focus of this paper is on parametric studies of SFT sections with changes in the section dimensions and the environmental loads to determine the potential for construction of a circular one-cell concrete SFT section. In advance, representative structural responses of SFT structure are investigated to suggest the initial design guidance for SFT. Comparison of numerical results obtained by ABAQUS and OrcaFlex validates the reliability of the proposed 3-D equivalent static approach, and effects of design variables on the structural safety are analyzed. Especially, comparative analyses of the section stresses are systematically performed to examine the influence of design variables on the section determination. Upon the results obtained from parametric studies, it can be concluded that the circular one-cell concrete SFT structures can be realized with only the placement of the minimum reinforcements for bending and shear.