Seismic retrofit Seismic retrofit Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent experiences with large earthquakes near urban centers, the need of seismic retrofitting is well acknowledged. Prior to the introduction of modern seismic codes in the late 1960s for developed countries (US, Japan etc.) and late 1970s for many other parts of the world (Turkey, China etc.), many structures were designed without adequate detailing and reinforcement for seismic protection. In view of the
Seismic risk the level of seismic hazard, the damage generally follows established patterns. Seismic risk is often determined using a seismic modeling computer programs which uses the seismic hazard inputs and combines them with the known susceptibilities of structures and facilities, such as buildings, bridges, electrical power switching stations, etc. The result gives probabilities for economic damage or casualties, for example the HAZUS computer program . While the results can be used as a general measure of seismic risk for types of buildings, the actual seismic risk for any individual building may vary considerably and will depend upon its exact configuration and