Conceptual Design of Tsunami Evacuation Infrastructure for Padang, Indonesia
Executive Summary
The Great Indian Ocean Tsunami of 2004 instantly brought tsunamis and tsunami preparedness to the forefront of global awareness. Hundreds of non-governmental organizations swarmed hard hit regions, the majority congregating in Banda Aceh, Indonesia which lost over half its population. The tragic consequences of the global ill-preparedness in 2004 with respect to tsunamis drives the current effort of scientists, engineers, government officials and local organizations around the world to focus on Padang, Indonesia which now has the highest risk from tsunamis in the world. Numerous studies have been performed with respect to evacuation planning and local risk, but this document addresses tsunami preparedness through the examination of tsunami evacuation plans to incorporate civil infrastructure in the form of buildings and bridges, including cost benefit assessments.In an effort to provide a holistic examination of Padang’s tsunami evacuation possibilities, this project is divided into five studies. The first study examines the seismic and tsunami hazard affecting Padang, including parameters critical to the design of civil infrastructure. The second study works to develop a methodology centered around built infrastructure solutions to evaluate evacuation plans. The last three studies examine different built infrastructure which may be aspects of a complete tsunami evacuation plan including bridges to aid in horizontal evacuations, new structures, and retrofits of existing structures for use in vertical evacuation. Conceptual designs of each infrastructure solution are presented in this project. Together, these five studies address a tsunami event from the origin at the rupture of the Sunda megathrust fault, through the tsunami inundation of Padang, and into the support of the surviving community for the days afterward.
It is important to note the following issues that are not within the scope of this project. This project does not try to develop new seismic or tsunami models for Padang. It also does not attempt to develop a new tsunami evacuation plan for Padang City. While this project addresses some forms of built infrastructure that may be part of a complete evacuation plan, there are additional systems such as roads or alternate vertical systems that should also be examined.
As a result of this project, the following recommendations are made with regards to tsunami evacuation planning for Padang City. An official tsunami hazard map, including tsunami wave inundation, is critical to inform any engineering or policy discussions and to allow Padang to move forward with tsunami preparedness. Infrastructure is a crucial component of tsunami evacuation planning, including aids to horizontal and vertical evacuation in the form of roads, bridges and appropriately designed structures. Structural shear walls may provide a more effective lateral force resisting system over the properly detailed concrete moment frame systems that would be required for a seismic and tsunami resistant building. Using existing structures for vertical evacuation may be the most effective way to provide large-scale evacuation points for a dense urban center like Padang. Detailed analysis of each potential building would need to be conducted and, if required, retrofit techniques can provide the performance required to allow the structure to serve as an evacuation site.
