To 3 or Not to 3? (View-Only)

Designing seismic force-resisting systems per AISC 341 permits the use of large R values (5 to 8), reducing seismic design forces, required frame and foundation strength, and stiffness requirements. However, this comes at a cost. Members must be seismically-compact, driving up steel tonnage; extensive lateral bracing of beams and columns may be required; and, connection designs must meet rigorous criteria that drive up complexity and cost. Where permitted as an alternative, design for R=3, requires design for higher forces, but often results in a more economical solution through avoidance of these AISC 341 requirements. This presentation will examine this trade-off and how the selection of a SFRS affects the total building cost, not just the steel tonnage.

Source: AISC Live Webinar (1/27/2026)

Speakers: Ron Hamburger, SE, PE and John Hooper, SE, PE

This content is free to view. If you would like to receive continuing education credit for this program, you can purchase the credit version here.