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A Direct Analysis Method for Drift-Sensitive Steel Moment Frames



John L. Harris


Design interaction equations for steel members in a moment frame are formulated based on inelastic member capacities that account for geometric imperfections, residual stresses, second-order effects, and, in some cases, eccentric loading. The analytical frame model used in structural analysis is commonly an idealized formulation of the system - with regard to geometry and material - so that all assumptions of the elastic analysis are preserved. Consequently, an incompatibility is produced between required member strengths from analysis results and member design strengths from interaction equations. To resolve this issue, AISC introduced a new design approach in the 2005 Specification for Structural Steel Buildings – AISC 360-05 (AISC, 2005a), Appendix 7 - Direct Analysis Method (DAM). In the 2010 Specification, the DAM will become the default design approach and moved to Chapter C; the current approach - Effective Length Method - will still be permitted (with modifications) and relocated to Appendix 7.
Proceedings Title
Proceedings of the 2009 SEAOC Annual Convention
Conference Dates
September 22-26, 2009
Conference Location
San Diego, CA


Seismic, Steel Moment Frame, Drift, Direct Analysis Method


Harris, J. (2011), A Direct Analysis Method for Drift-Sensitive Steel Moment Frames, Proceedings of the 2009 SEAOC Annual Convention, San Diego, CA (Accessed April 23, 2024)
Created February 17, 2011, Updated June 2, 2021