Offshore disasters: wave forces on offshore and coastal structures due to Tsunamis

Abstract

Every year natural disasters result in considerable damage to offshore structures, coastal zones and other vulnerable areas. In Tsunami disasters direct damage occurs, such as the destruction of structures and loss of life due to wave forces and the run-up Tsunami. Tsunamis are characterised as shallow water waves of long period wavelength with extreme height and force. They are often observed with wavelengths in excess of 150 Km and with periods of over 1.5 hours. Due to their large wavelength and wave force, Tsunamis propagate high wave forces and loads. This paper has three main sections. Characteristics of waves, which includes waves with a crest at the top and a trough at the bottom, wave forces and damage to offshore structures, the design of wave methodology for safer structures; Physical characteristics of Tsunamis, considering the mitigation of risk and hazard, wave force estimation, design of offshore and coastal structures to allow for Tsunamis; Managing natural disasters. This paper provides a close study and literature review on the engineering approach to the design of wave forces and reports on a proposed structural design method for Tsunami refuge building based upon a literature survey of previous theoretical and experimental research on Tsunami forces and loads to offshore and coastal structures. The paper also proposes a verification approach requiring a generalised model of the structure of interest to minimise the risk and damage to structures. Disaster Management and Human Health Risk 251 doi:10.2495/DMAN090231 © 2009 WIT Press www.witpress.com, ISSN 1743-3509 (on-line) WIT Transactions on The Built Environment, Vol 110,