The Northridge earthquake of January 17, 1994, caused widespread building damage throughout some of the most heavily populated communities of Southern California including the San Fernando Valley, Santa Monica and West Los Angeles, resulting in estimated economic losses exceeding $30 billion. Much of the damage sustained was quite predictable, occurring in types of buildings that engineers had previously identified as having low seismic resistance and significant risk of damage in earthquakes. This included older masonry and concrete buildings, but not steel framed buildings. Surprisingly, however, a number of modern, welded, steel, moment-frame buildings also sustained significant damage. Engineers did not have clear guidance on how to detect damage, repair the damage they found, assess the safety of existing buildings, upgrade buildings found to be deficient or design new steel moment-frame structures to perform adequately in earthquakes.
In response to the many concerns raised by these damage discoveries, the Federal Emergency Management Agency (FEMA) sponsored a program of directed investigation and development to identify the cause of the damage, quantify the risk inherent in steel structures and develop practical and effective engineering criteria for mitigation of this risk.
Federal Emergency Management AgencyReview the quiz before studying the course.
Acrobat Reader is required to view this document. Click here to download a free copy of Acrobat Reader.