Vibration characteristics of submerged floating tunnels with suspension cables according to wave periods

Abstract

The tension leg method is typically used for the mooring of submerged floating tunnels (SFTs). These tunnels may have mooring lines and foundations installed very close together, depending on the wave conditions. Sometimes, the construction cost can be increased by the foundation design. To overcome these weaknesses, a suspension SFT using the mechanism of a suspension bridge has been proposed. In this approach, the tunnel body is connected to fixed towers at both ends. Two main cables are installed for controlling the tunnel motion. The main cables are connected to the tunnel using hangers. The main cable is a steel pipe and filled with water to increase its weight. The main cables are arranged in an arch shape for controlling the buoyancy weight ratio (BWR) of the tunnel body. The present study analyzed the vibration characteristics of a suspension SFT using the free vibration analysis and time-domain analysis techniques. The study demonstrates that the SFT has excellent self-vibration control. The suspension SFT affected tuned mass damping via the interaction between the tunnel body and main cables.