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Dynamic analysis of floating bridges under combined earthquakes and waves

  • Ikjae Lee (Department of Ocean Engineering, Texas A&M University) ;
  • Moohyun Kim (Department of Ocean Engineering, Texas A&M University) ;
  • Jihun Song (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Seungjun Kim (School of Civil, Environmental and Architectural Engineering, Korea University)
  • Received : 2024.03.22
  • Accepted : 2024.05.25
  • Published : 2024.06.25

Abstract

In this study, numerical study of a long, straight, side-anchored floating bridge with discrete pontoons subjected to combined earthquakes and waves is conducted. Ground motions with magnitude corresponding to 200 YRP (years return period) earthquake in South Korea are generated based on the spectral matching method from a past earthquake record in California. Several sensitivity studies are carried out for bridge end condition, for different site classes (hard rock S1 and soft and deep soil S5), and for three different excitations (earthquake only, wave only, and earthquake-wave combined). Bridge and pontoon motions, bending moments along the bridge, and mooring tensions are systematically examined through coupled time-domain simulations by commercial program OrcaFlex. The numerical results show that the impact of earthquakes on floating bridges is still of importance especially for soft soil although ground motions are less directly applied to the structure than fixed bridges.

Keywords

Acknowledgement

This work was supported by a Korea Agency for Infrastructure Technology Advancement (KAIA) grant funded by the Ministry of Land, Infrastructure, and Transport (Grant RS-2023-00250727) through the Korea Floating Infrastructure Research Center at Seoul National University.

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