All are built over large geographic areas and are therefore subject to many different hazards. They comprise many different structures and types of equipment, are fabricated with different materials, and are constructed over many years according to different design practices and levels of workmanship. When an earthquake strikes a lifeline system, there can be a wide variety of responses, all of which affect the ability of the system to provide critical resources, such as water to extinguish fires triggered by the earthquake or electric power for emergency equipment. I look very closely at the behavior of underground pipeline systems and conduits. So the outcome in terms of survivability and the way in which these systems function are directly tied to the behavior of the ground.
Tunnels are underground structures that are critical parts of lifeline networks.
Tunnels are used for highways, railroads, metros, drinking water conveyance, and the storage and transportation of wastewater. They also can house electric power and telecommunications equipment. I am currently involved in the seismic design of highway tunnels in Turkey. I provide advice to an international team that is designing and constructing very important tunnels linking Istanbul and Ankara. A severe earthquake that struck Turkey in November 1999 damaged parts of the highway tunnels.