Effect of near-field earthquake excitation on seismic behavior of knee-braced moment frames
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Inelastic behavioral characteristics of knee-braced moment-resisting frames having 3, 8 or, 12 stories were investigated under near-source earthquake excitation using initially pinned frames that were subsequently substituted with rigid knee elements. These frames were designed so that the knee braces would yield and buckle under seismic loading. Inelastic time-history analysis was carried out to assess the structural performance of the buildings by evaluating the maximum axial forces of the columns, vertical displacement of internal beams, roof horizontal displacement, and maximum base shear of columns in the building members using PERFORM-3D software. The nonlinear behavior of the frames was investigated by comparing the results of pinned and rigid knee elements subjected to near-field earthquakes. The results indicate that rigid-to-pinned connections for knee elements can increase the axial forces of columns by nearly 15% for a 3-story building and about 7% for 8- and 12-story buildings. The vertical displacement of the beams was noticeable, especially for the three-story building. The horizontal displacement of the roof and base shear of columns using pinned connections for knee elements were generally greater than for the rigid connections.
KeywordsNear-field earthquake Knee elements Steel structures Knee-braced moment frames
The author would like to express his deepest gratitude to Dr. Hossein Abdollahiparsa and Dr. Mitra Heydari for always giving encouragement and providing invaluable suggestions.
- BHRC (Building and Housing Research Center). (2005). Iranian code of practice for seismic resistant design of buildings, standard no. 2800-05 (3rd ed.). Tehran: Building and Housing Re-search Center.Google Scholar
- Bruneau, M., Uang, C. M., & Whittaker, A. (1998). Ductile design of steel structures. New York: McGraw-Hill.Google Scholar
- Clément, D., & Williams, M. (2004). Seismic design and analysis of a knee braced frame building. Journal of Earthquake Engineering, 8(4), 523–543.Google Scholar
- Conti, M., Mastrandrea, A., & Piluso, V. (2009). Plastic design and seismic response of knee braced frames. Advanced Steel Construction, 5(3), 343–366.Google Scholar
- CSI (Computers and Structures Inc.). (2011). Structural and earthquake engineering software, PERFORM-3D, nonlinear analysis and performance assessment for 3-D structures, Version 5.0.0, Berkeley.Google Scholar
- Di Sarno, L., & Elnashai, A. S. (2002). Seismic retrofitting of steel and composite building structures. IL: Mid-America Earthquake Center Report, CD Release 02-01, University of Illinois at Urbana-Champaign.Google Scholar
- Maheri, M. R., & Akbari, R. (2003). Seismic behaviour factor. R, for steel X-braced and knee-braced RC buildings, Engineering Structures, 25(13), 1697–1705.Google Scholar
- Roeder, C. W., & Popov, E. P. (1978). Eccentrically braced steel frames for earthquakes. Journal of Structural Division, ASCE, 104(3), 391–412.Google Scholar