"Much of the nation's work regarding performance-based seismic design has been funded by the Federal Emergency Management Agency (FEMA), under its role in the National Earthquake Hazards Reduction Program (NEHRP). Prevailing practice for performance-based seismic design is based on FEMA 273, NEHRP Guidelines for the Seismic Rehabilitation of Buildings (FEMA, 1997) and its successor documents, FEMA 356, Pre-standard and Commentary for the Seismic Rehabilitation of Buildings (FEMA, 2000), and ASCE/SEI Standard 41-06, Seismic Rehabilitation of Existing Buildings (ASCE, 2006b). This series of documents has been under development for over twenty years, and has been increasingly absorbed into engineering practice over that period. The FEMA 440 report, Improvement of Nonlinear Static Seismic Analysis Procedures (FEMA, 2005), was commissioned to evaluate and develop improvements to nonlinear static analysis procedures used in prevailing practice. Recommendations contained within FEMA 440 resulted in immediate improvement in nonlinear static analysis procedures, and were incorporated in the development of ASCE/SEI 41-06. However, several difficult technical issues remained unresolved."
Federal Emergency Management Agency (FEMA): http://www.fema.gov/