Understanding the response of coastal infrastructure to tsunami impacts

• Main Author: Chua, Constance Ting
• Other Authors: Adam D. Switzer
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Science::Geology; Engineering::Civil engineering
• Online Access: https://hdl.handle.net/10356/151779
• Institution: Nanyang Technological University

The study of tsunami damage has gained momentum since the 2004 Indian Ocean tsunami. However, as most studies are focused on building damage, our understanding of the impacts of tsunami on coastal infrastructure such as ports and other critical facilities is still limited. Structural fragility is commonly quantified by fragility functions. Tsunami fragility functions describe the relationship between the probability of exceeding a predefined threshold of structural damage and tsunami flow characteristics. In this present study, I develop damage fragility functions for eight common port industries based on observations from the 2011 Tohoku tsunami to characterise the structural fragility of port structures. A systematic methodology is used to assess damage and a damage database consisting of damage information to more than 5000 port structures is established. In fragility modelling, tsunami flow characteristics are represented by tsunami intensity measures (TIM). Typically, observed flow depth is used as a TIM because it is directly measurable from the field. Increasingly, studies have included other TIM such as velocity and hydrodynamic force. Several studies have debated the choice of TIM used in fragility models. However, a TIM is a simplified representation of the tsunami hazard and I postulate that different tsunami flow characteristics, and essentially TIM, contribute to damage differently. In this study, I evaluate the relative influence of TIM on the damage observed to port structures in the 2011 Tohoku tsunami. Inundation depth was found consistently be the most influential parameter and fragility models using inundation depths as the sole TIM provided the most accurate damage estimates.