Plastic hinge location in columns of steel frames subjected to seismic actions

Abstract

Several steel structure standards around the world contain an equation to encourage any column flexural yielding during earthquake shaking to occur at the column ends, rather than along the column length. The accuracy of these equations and their applicability to columns of both moment frames and braced frames are examined in this paper. It is shown, using an analytical procedure developed from first principles considering the reduction in member stiffness from axial force due to geometric and material nonlinearity, that the existing code equations are conservative. Less conservative empirical equations are developed based on the analysis results. It is found that these equations are applicable to frames with a braced connection, rather than a moment connection into the column. Time-history analysis of eccentrically-braced frames with inverted V-bracing, where the active link occurs at the centre of the beam, is carried out. The likely column end moment ratio needed for the new equations is determined. The analysis also shows that yielding often did not occur in the bottom story columns during earthquake excitations. A simple check is proposed to relate the axial force limit and the design drift to flexural yielding of columns which can be used in conjunction with the proposed equations.

References

The MathWorks Inc. (2005). "MATLAB." MathWorks Inc., Natick, MA, USA.

American Institute of Steel Construction. (2005). Manual of steel construction : load and resistance factor design, American Institute of Steel Construction, Chicago, Ill.

Carr, A. J. (2004). "Ruaumoko." Department of Civil Engineering, University of Canterbury, Christchurch.

Dr. Software, L. (1998). "Dr. Frame 2D." Dr. Software, LLC, Seattle.

Hyland, C. (2005). "Seismic Design of Steel Structures: Eccentrically Braced Frames." Steel Construction New Zealand, Auckland.

Lay, M. G. (1964). "The Static Load Deformation Behaviour of Planar Steel Structures," PhD Thesis, Lehigh University, Bethlehem.

Lay, M. G. (1975). Source book for the Australian steel structures code - AS 1250, Australian Institute of Steel Construction, Sydney.

MacRae, G. A. (1990). The seismic response of steel frames, PhD Thesis, Department of Civil Engineering University of Canterbury, Christchurch.

Peng, B. H. H. (2006). "Plastic Hinge Location in Columns of Steel Frames." Research Report No. 2006-05, Department of Civil Engineering, University of Canterbury, Christchurch.

Silva, W. (2000). "PEER Strong Motion Database." University of California.

Standards Australia. (1998). Australian Standard: Steel Structures AS 4100: 1998, Standards Australia, Sydney.

Standards New Zealand. (1997). Steel structures standard NZS3404, Standards New Zealand, Wellington.

Standards New Zealand. (2004). Structural design actions NZS 1170.5, Standards New Zealand, Wellington.

Published
2008-03-31
How to Cite
Peng, B. H. H., MacRae, G. A., Walpole, W. R., Moss, P., Dhakal, R., & Clifton, C. (2008). Plastic hinge location in columns of steel frames subjected to seismic actions. Bulletin of the New Zealand Society for Earthquake Engineering, 41(1), 1-9. https://doi.org/10.5459/bnzsee.41.1.1-9
Section
Articles

Most read articles by the same author(s)

1 2 > >>