Seismic disadvantages and formation mechanism of weak coupling effects in interconnected power infrastructures

• Published in: Soil dynamics and earthquake engineering (1984) 2023-10, Vol.173, p.108082, Article 108082
• Main Authors: Wen, Jiayi, Li, Xiaoxuan, Xie, Qiang
• Format: Article
• Language: English
• Subjects: Complex-mode vibration; Formation mechanism; Mode transition; Power infrastructures; Weakly coupling
• ISSN: 0267-7261
• DOI: 10.1016/j.soildyn.2023.108082

Power infrastructures consist of cantilever-post facilities interconnected by highly flexible conductors, which cause weak coupling effects and significantly threaten seismic performances. However, understanding the weak coupling effect remains intuitive and empirical, particularly in terms of its formation mechanism. Using an established separation-based method, which ensures sufficient consideration of the weak coupling effect, a model of a coupled system with continuous-parameter coupling parts was examined. Most notably, complex-mode vibration was found to be an intrinsic outcome of weak coupling effects, which contributes to the seismic disadvantages. Furthermore, the transition and selective expression of vibration modes comprehensively explained the formation of the weak coupling effect. These properties contradict the preconditions of general analysis approaches, such as the well-known mode-superposition method, which, when applied to a weakly coupled system, can significantly underestimate seismic responses. These findings imply that specific awareness and appropriate consideration of weak coupling effects are required for power infrastructure analysis and design. •The lack of global vibration modes of a weakly-coupled system was attributed to its inherent complex-mode vibration.•Common methods relying on global modes will bring significant errors under the weak coupling condition.•Formation mechanism of weak coupling effects was explained via a theory of modal transition and selective expression.•Weak coupling effects will be suppressed when a largely-damped connection component is employed.