Evaluating Damage Spectra for Steel Braced Frames Due to Near-Field and Far-Field Earthquakes

Recent ground motion records demonstrate that the near-field earthquakes have various properties compared to far-field earthquakes. In general, most of these properties are affected by an important phenomenon called ‘forward directivity’ in near-fault earthquakes. Measuring structural damages are one of the common activities administered after an earthquake. Predicting the amount of damage caused by the earthquake as well as determining the vulnerability of the structure is extremely significant. In order to measure the amount of structural damages, instead of calculating the acceleration and velocity spectrum, it is possible to use the damage spectra of the structure. The damage spectrum is a kind of nonlinear spectrum that is drawn by setting the nonlinear parameters related to the single degree of freedom structures and its dynamic analysis under the specific record and measuring damage of any structure. In this study, the damage spectra of steel structures have been drawn. For this purpose, different kinds of concentric and eccentric braced structures with various ductility coefficients in hard and soft soil under near-field and far-field ground motion records have been considered using the Krawinkler and Zohrei damage index. The results indicate that, by increasing the structures' fundamental period, the amount of damage increases under the near-field earthquakes compared to far-field earthquakes. In addition, by increasing the structure ductility, the amount of damage based on near-field and far-field earthquakes decreases noticeably. Furthermore, in concentric braced structures, the amount of damage under the near-field earthquakes is almost two times more than the amount of damage in eccentrically braced structures especially for fundamental periods larger than 0.6 s.

• A. Yousefi
• B. Mohebi
• M. A. Rostamkhani

• Damage spectra
• damage index
• forward directivity
• near-field earthquakes
• far-field earthquakes.

[1] Bannon H, Veneziano D. 1982. Seismic safety of reinforced concrete members and structures. Earthquake Engineering and Structural Dynamics. 10: 179–193.
[2] Krawinkler, H., and Zohrei, M., "Cumulative damage in steel structures subjected to earthquake ground motions", Journal on Computers and Structures, Vol. 16, No. 1-4, (1983).
[3] Park Y-J, Ang A H-S. Seismic Damage Analysis of RC Buildings. Journal of Structural Engineering, ASCE. Vol. 111, pp. 740-757, (1985).
[4] Kratzig, W. B., and Meskouris, K. ~1997!. ‘‘Seismic damage evaluation treated as a low-cycle fatigue process.’’ Seismic design methodologies for the next generation of codes, P. Fajfar and H. Krawinkler, eds., Balkema, Rotterdam, The Netherlands, 139–149
[5] Powell H. Graham and Allahabadi R. "Seismic damage prediction by deterministic methods" Concepts and Procedures, Erthquake Engineering and Structural Dynamics, Vol. 16, 719-734, (1988).
[6] Ghobara, H. Abou-Elfath, H Shrif Biddah, Response-Based Damage Assessment Of Structures, Earthquake Engineering Structure Dynamics, vol 28, pp. 79-104, (1999).
[7] Bozorgnia, Y., and Bertero, V. V. ‘‘Damage Spectra: Characteristics and Applications to Seismic Risk Reduction.’’ Journal of Structural Engineering © ASCE, (2003).
[8] Estekanchi, H., Arjomandi, K. and Vafai, A. Estimating structural damage of steel moment frames by endurance time method", Journal of Constructional Steel Research, 2007.05.010, 64(2), pp 145-155 (2007).
[9] Anderson, James C., and Farzad Naeim. "Design criteria and ground motion effects in the seismic response of multi-storey buildings." Proc. Applied Technology Council, ATC 104 (1984).
[10] Somerville, P. "The Characteristics and Quantification of Near Fault Ground Motion. "Proceedings of the FHWA/NCEER Workshop on the National Representation of Seismic Ground Motion for New and Existing Highway Facilities. Burlingame, California, May 29-30,293-318, (1997).
[11] Alavi B, Krawinkler H. Effects of near-fault ground motions on frame structures. The John A. Blume Earthquake Engineering Research Center, Report No. 138, Feb. (2001).
[12] Bozorgnia Y, Bertero V. V.. Evaluation of damage potential of recorded earthquake ground motion. Seismological Research Letters; 72,233, (2001).
[13] Kunnath, S. K., Reinhorn, A. M., & Lobo, R. F. (1992). IDARC Version 3.0: A program for the inelastic damage analysis of reinforced concrete structures.
[14] Arjomandi, H. Estekanchi and A. Vafai, Correlation Between Structural Performance Levels and Damage Indexes in Steel Frames Subjected to Earthquake; Scientia Iranica, Vol. 16, No. 2, pp. 147-155, (2009).
[15] LRFD, AISC. "American Institute of Steel Construction (AISC)." Load and resistance factor design. Chicago: AISC, 2010.
[16] McKenna, F., Fenves, G.L. and Scott, M.H., 2015. Open system for earthquake engineering simulation. University of California, Berkeley, CA.