Analysis of the importance coefficient of offshore bridges under earthquakes based on seismic fragility and incremental dynamic analysis

• Published in: Soil dynamics and earthquake engineering (1984) Vol. 171; p. 107987
• Main Authors: Yan, Jialei, Liang, Yan, Du, Xin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2023
• Subjects: Continuous damage; Earthquake; Importance coefficient; Offshore bridge; Reliability theory; Seismic fragility; Reliability theory; Offshore bridge; Earthquake; Importance coefficient; Seismic fragility; Continuous damage
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/j.soildyn.2023.107987

Focusing on the continuous damage and seismic-induced stability of offshore bridges, this paper presents an optimized quantification of the importance coefficient of bridges subjected to earthquakes. First, the time-depending durability analysis model of materials, probabilistic seismic demand model, damage indicator analysis, and input of earthquake ground motions are investigated. Subsequently, using incremental dynamic analysis, fragility, and reliability, a quantitative criterion of the importance coefficient for offshore bridges is proposed. Thereafter, a case of an offshore bridge is analyzed, including the description, finite-element modeling method, the efficient and refined simulation of materials, construction of the damage indicator, and classification of collapse scenarios, also, the collapse resistance of bridges under earthquakes. This study indicates that the importance coefficient increases with the extension of the service time, the time-depending durability damage effects have a significant influence on the importance coefficient. The mainshock-aftershock sequence is vital to the importance coefficient of a bridge during the whole life cycle, and the bridge will still have a certain service performance when it exceeds its design service life. •Time-varying concrete carbonization, chloride erosion and bond slip are considered.•An importance coefficient algorithm of bridge subject to earthquakes is proposed.•Main aftershock has a great influence on importance coefficient of bridges.•Bridges still have certain service performance after reaching the service period.