Tuned mass damper application for submerged floating tunnel under wave and seismic excitations

Abstract

This study investigates the feasibility of the tuned mass damper (TMD) for vibration control of submerged floating tunnel (SFT). TMD was positioned at tunnel’s mid-length to dampen a lateral vibration, especially at the fundamental lateral natural frequency. Coupled time-domain dynamics simulation that solves the interaction between SFT and TMD was conducted under random wave and seismic excitations. TMD’s spring/damping coefficients were optimized by the harmony search (HS) algorithm. HS and time-domain dynamics model were externally coupled to perform an iterative procedure of generating spring/damping coefficients according to the HS rules, conducting coupled time-domain simulation with generated coefficients, and analyzing the results by HS. The effect of TMD’s mass was separately evaluated through a parametric study. After parameter optimization, SFT dynamics with and without TMD was analyzed. TMD especially plays an important role in vibration mitigation when the frequency range of environmental loads is close to the fundamental lateral natural frequency.