Presenting a New Model to Evaluate Damaged Steel Structures after an Earthquake with the Aim of Managing Emergency Conditions

Document Type : Articles

Authors

1 M.Sc. Graduate in Earthquake Engineering, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran

2 . Associate Professor, Structural Engineering Research Center, International Institute of Earthquale Engineering and Seismology (IIEES), and President of Iranian Earthquake Engineering Association, Tehran, Iran

Abstract

In general, determining the seismic behaviour of a building damaged by an earthquake is a difficult and complex task. This issue is important and practical in today's world because demolishing of all the buildings damaged by the earthquake is very expensive and time-consuming. For this purpose, in the first step of the reconstruction of an earthquake-stricken city, it should be determined which buildings are useable and safe, which buildings are repairable, and which ones should be demolished. The repairability, destructibility or usability and safety of a damaged building is effective when the seismic behaviour of that building can be determined after the damage. To determine the seismic behaviour of the building damaged by the earthquake, some methods have been presented by other researchers. However, most of these methods need to spend a lot of time to check the behaviour of the structure. The purpose of this research is to provide a new analytical method for the seismic evaluation of steel moment frame structures damaged in an earthquake, which can determine the force-displacement curve of a steel structure for different levels of damage. Also, in this research, with the benefit of SPO2IDA's approximate analysis, a method for classifying damaged structures based on the percentage of damages has been presented. For this purpose, a three-story steel moment frame structure was subjected to nonlinear static analysis in OpenSEES Software. Then, using the proposed method to analyse the damaged structure and considering the cyclic deterioration of the damaged members and elements by modifying the behaviour curves of the structure, non-linear static analysis curves were extracted for different levels of damage. In the method of cyclic deterioration of damaged elements, based on the amount of rotation or deformation occurred in the member during the earthquake, the performance curve of the member changes in such a way that these changes include stiffness, resistance and ductility. According to the initial back-bone curve, four levels of damage were meant for the damaged structures, and each of these damage levels is dependent on the amount of reduction in resistance that occurred in the initial back-bone curve of the structure.
Also, using the SPO2IDA method, the approximate curves obtained from incremental dynamic analysis were extracted for the analysed structure. Then, by using these curves, the proposed procedure was evaluated in order to classify the structures after the earthquake. At the end, the results of this method are compared with the methods proposed by others in each step, and the crucial differences in response are fully explained. It was shown that at different performance levels, by not considering the effects of cyclic distortion, between 30% and 50% of the structure's capacity will be estimated higher. According to the obtained results, in the event of an aftershock with a magnitude close to the main shock, it can be concluded that not considering the cyclic distortion in the behaviour of the damaged members and elements can lead to many mistakes in decision and classification of the structures which result to irreparable consequences.

Keywords


ATC. (1989). Procedures for Post-Earthquake Safety Evaluation of Buildings, ATC-20. Applied Technology Council, Redwood City, CA.
ATC 35. (1999). Earthquake Aftershocks-Entering Damaged Building. Applied Technology Council, Redwood City, California. Technical Brief 2.
Bazzurro, P., Cornell, C.A., Menun, C., and Motahari, M. (2002). Advanced Seismic Assessment Guidelines. Report Prepared for PG&E, PEER Lifelines Program, Task 501 and Draft 1.
D’ayala, D., Meslem, A., Vamvatsikos, D., Porter, K., Rossetto, T., Crowley, H., & Silva, V. (2014) Guidelines for Analytical Vulnerability Assessment of Low/Mid-Rise Buildings: Methodology. Vulnerability Global Component Project.
FEMA 306. (1998). Evaluation of Earthquake Damaged Concrete and Masonry Wall Buildings– Basic Procedures Manual. Federal Emergency Management Agency, Washington, DC.
Fragiacomo, M., Amadio, C., & Macorini, L. (2004). Seismic response of steel frames under repeated earthquake ground motions. Engineering Structures, 26(13), 2021-2035.
Fragiadakis, M., & Vamvatsikos, D. (2010). Fast performance uncertainty estimation via pushover and approximate IDA. Earthquake Engineering & Structural Dynamics39(6), 683-703.
Hatzigeorgiou, G.D., & Beskos, D.E. (2009). Inelastic displacement ratios for SDOF structures subjected to repeated earthquakes. Engineering Structures, 31(11), 2744-2755.
Hosseini Hashemi, B., & Naserpour, A. (2015). Performance evaluation of the damaged steel moment frames under mainshock-aftershock sequences considering plastic hinge modification factors. Journal of Seismology and Earthquake Engineering, 16(4).
Lee, K., & Foutch, D.A. (2004). Performance evaluation of damaged steel frame buildings subjected to seismic loads. Journal of Struct. Eng., 130, 588-599.
Li, Q., & Ellingwood, B.R. (2007). Performance evaluation and damage assessment of steel frame buildings under main shock–aftershock sequences. Journal of Earthq. Eng. Struct. Dyn., 36, 405-427.
Li, Y., Song, R., van de Lindt, J., Nazari, N., & Luco, N. (2012). Assessment of wood and steel structures subjected to earthquake mainshock-aftershock. In 15th World Conference on Earthquake Engineering, Lisbon, Portugal.
Luco, N., Bazzurro, P., & Cornell, C.A. (2004). Dynamic versus static computation of the residual capacity of a mainshock-damaged building to withstand an aftershock. In 13th World Conference on Earthquake Engineering.
Maffei, J., Telleen, K., Mohr, D., Holmes, W., & Nakayama, Y. (2005). Test Applications of Advanced Seismic Assessment Guidelines: Report 2005/09.
Mahin, S.A. (1980). Effects of duration and aftershocks on inelastic design earthquakes. In Proceedings of      the Seventh World Conference on Earthquake Engineering, 5, 677-680.
Mazzoni, S., McKenna, F., Scott, M.H., Fenves, G.L., & Jeremic, B. (2015). Open System for Earthquake Engineering Simulation (OpenSees). Available: http://opensees.ce.berkeley.gatech.edu.
Naserpour, A., & Hosseini Hashemi, B. (2015). Performance Evaluation of Special Steel Moment Frames Under the Sequences of Mainshock-Aftershock. M.Sc. Thesis, International Institute of Earthquake Engineering and Seismology.
Ruiz-García, J., & Negrete-Manriquez, J.C. (2011). Evaluation of drift demands in existing steel frames under as-recorded far-field and near-fault mainshock–aftershock seismic sequences. Engineering Structures, 33(2), 621-634.
Vamvatsikos, D. (2002) SPO2IDA Software for Short, Moderate and Long Periods. Available: http://tremble. Stanford.edu/nausika/software/spo2ida-allt.
Vamvatsikos, D., & Cornell, C.A. (2002). Incremental dynamic analysis. Earthquake Engineering & Structural Dynamics31(3), 491-514.
Vamvatsikos, D., & Cornell, C.A. (2004). Applied incremental dynamic analysis. Earthquake Spectra, 20(2), 523-553.
Vamvatsikos, D., Jalayer, F., & Cornell, C.A. (2003). Application of incremental dynamic analysis to an RC-structure. In Proceedings of the FIB Symposium on Concrete Structures in Seismic Regions (pp. 75-86).
Yeo, G.L., & Cornell, C.A. (2009). A probabilistic framework for quantification of aftershock ground- motion hazard in California: Methodology and parametric study. Earthquake Engineering & Structural Dynamics38(1), 45-60.