Submerged Floating Tunnels: State-of-the-Art on Design and Challenges

Submerged Floating Tunnel (SFT) is an alternative and new way of crossing seas and oceans at relatively deeper waters so that storms or tsunamis do not affect the transportation. SFT has distinct and significant advantages over conventional structures like concrete or suspension bridges and immersed tunnels in trans-oceanic transportation. The present paper reviews the reported studies on SFTs and discusses its design and structural features. Though reported studies on SFTs are limited in number, an attempt has been made to review the research status and summarize the findings on analysis and design methodologies of its structural components, namely, the tubes, foundation systems, anchoring tethers, and shore connection. Since there is still no functional SFT structure anywhere in the world, the present paper also discusses the challenges in design and construction of this kind of tunnel, namely, hydrodynamic response of the tube and the foundation system, and tunnel safety analysis.