Long-term Issues and References

Needs for Performance Codes

The methods described in the previous pages (FEMA 273, SAC, etc.) are currently being used on an ad hoc basis for important new and existing buildings. These documents are only the first steps in developing Performance Based Codes. Much work is needed to evaluate and validate the methodologies that have been developed. Also, improved tools are needed for analysis and design, and more tests are needed to quantify various performance targets.

To date, the focus has been only on structural performance. In general, economic issues must be considered as well. Initial costs need to be compared with "life cycle" costs to determine the design that performs best. Economic costs also depend on who pays for the damage - the owner, insurance, or the government.

Longer Term Issues

  • A consistent reliability oriented computer-assisted design methodology is needed, but this may be too complex for routine design. However, it would be useful for developing or calibrating simpler code methods and for complex and important projects.
  • Existing buildings are not typically rehabilitated to the same level of reliability as new structures. However, whether this is good public policy, and the manner in which this is treated, needs investigation.
  • Social impacts of having many buildings damaged need to be considered in developing seismic codes. An earthquake is like an airplane crash -- both get more attention and have greater impact than individual distributed auto accidents or house fires.
  • Some of these issues are addressed in the EERC/FEMA action plan for performance based design.

References for Performance Based Design Codes

  • Hamburger, R. O., Performance Based Analysis and Design Procedure for Moment Resisting Steel Frames, Background Document, SAC Steel Project, September 10, 1998.
  • Federal Emergency Management Agency, NEHRP Guidelines for the Seismic Rehabilitation of Buildings (FEMA Publication 273), Washington DC, 1997.
  • Earthquake Engineering Research Center, Performance-based Seismic Design of Buildings: An Action Plan, U.C. Berkeley, 1995.
  • International Conference of Building Officials (ICBO), Uniform Building Code, Whittier, CA, 1994, 1997.
  • Structural Engineers Association of California, Vision 2000 - A Framework for Performance-based Design, California Office of Emergency Services, 1995.
  • Structural Engineers Association of California, Recommended Lateral Force Requirements and Commentary, Seismology Committee, San Francisco, April 1996.
  • U.S. Department of Defense, Design Guidelines for Essential Buildings, Army TM 5-809-10-1, Navy NAVFAC P-355-1, Air Force ARM 99-3, Chapter 13, Section A, Washington, DC, 1986.