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2023-12-05

AISC 341 Limit State Types

Which Limit State Types are applicable for the AISC 341 seismic design?


Answer:

The Earthquake Limit State (with and without overstrength) only provides a result for members with an assigned Seismic Configuration.
The Strength Limit State is used to design all members, including the members that are not part of the seismic force-resisting system (SFRS). Therefore, both Earthquake and Strength Limit States are required.
The Serviceability Limit State is also available.

Image 01 is an example of the required design situations for the LRFD Design.

Notes:
1) The web ductility check per Table D1.1 of AISC 341‑16 (RFEM EQ 1100) is applicable to all load combinations, including non-seismic COs. Therefore, the Earthquake Limit State is also applied to Equations 1 to 5 (Design Situation DS5 in Image 01).

2) For the Combination Wizard, the “Result Combinations” is required when using the response spectrum analysis.


Author

Cisca is responsible for customer technical support and continued program development for the North American market.