Changes to the Seismic Design of Steel Structures

September 11, 2019 @ 12:30 pm – 2:00 pm

Speaker: Jim O. Malley, SE
Degenkolb Engineers


On January 14, 1994, a M6.7 earthquake hit Southern California causing over $10 billion of damage. One of the most unexpected types of structural damage from the Northridge earthquake occurred in steel moment resisting frames, which prior to the earthquake had been considered one of the best seismic systems by many practicing structural engineers. Damage to over 100 such buildings created great concern in the structural engineering community, leading to a six-year, $10 million dollar FEMA funded research and development effort known as the SAC Steel Project.

SAC was a joint venture of the Structural Engineers Association of California, the Applied Technology Council, and the Consortium of Universities for Research in Earthquake Engineering, and the project’s investigations led to the development of a series of guidelines documents for use by practicing structural engineers. Many of the recommendations were incorporated into the AISC Seismic Provisions, and are now required for projects in the U.S. and widely used in many other countries throughout the world. These changes are based on a consistent methodology intended to result in excellent seismic performance of steel structures.

This SE University presentation will focus on the damage caused by the Northridge Earthquake, the response by the SAC Steel Project, and the changes to practice that have resulted.


Learning Objectives

  • Understand how the damage caused to steel moment frames by the 1994 Northridge earthquake led to major changes to seismic design of steel structures.
  • Realize that the basis for the overall design philosophy is rooted in developing a target inelastic mechanism with designated ductile structural fuses that dissipate the major of the earthquake’s energy.
  • Understand how design requirements for the various structural systems are designated to meet the seismic design philosophy.

Handout and registration emails for this session will be sent to SE University companies on Friday, September 6th.