Effect of Torsional Irregularity on Seismic Performance of Steel Moment Resisting Frame Structures

Document Type : Original Article


1 M.Sc. Student, Department of Engineering, Aletaha Institute of Higher Education, Tehran, Iran

2 Assistant Professor, Faculty of Civil Engineering, Amirkabir University of Technology, Tehran, Iran


This paper examines the seismic damage of three-dimensional steel moment-resisting frame (SMRF) structures affected by torsional irregularities. Six steel 3-D SMRF structures with varying degrees of irregularity were evaluated using incremental dynamic analysis (IDA) to determine their dynamic capacity. The aim of the study was to develop a quantifiable damage index based on the results of IDA. The yield point and the point of loss of lateral bearing (collapse threshold) on the IDA curve of each record were used to calculate the proposed damage index, which ranges from 0 to 1 and can be calculated individually in two horizontal directions. The study evaluated the feasibility of a meaningful match between the momentary torsion and the predicted damage by charting the ratio between these two quantities against the damage index findings. The analysis of the average damage at different levels of mild, medium, and high damage, as well as the comparison of the average damage index between the design accelerations corresponding to the return periods of 475 and 2475 years, revealed a general trend towards higher damage in structures with greater irregularity.


1-Bhasker, R., and Menon, A., 2020, Torsional irregularity indices for the seismic demand assessment of RC moment resisting frame buildings, Structures, 26, 888–900.
2-Mohammadzadeh, B., and Kang, J., 2021, Seismic analysis of high-rise steel frame building considering irregularities in plan and elevation, Steel Composite Structure, 39, 65–80.
3-Sancıoğlu, S., Vural, H. B., Selen, S., Çarbaş, S., and İlgün, A., 2022, Prevention of torsional irregularity in steel structures via brace members, Adv Eng Days, 2, 72–75.
4-Khanal, B., and Chaulagain, H., 2020, Seismic elastic performance of L-shaped building frames through plan irregularities, Structures, 27, 22–36.
5-Phadnis, P. P., and Karjinni, V. V., 2019, Fragility curves for steel–concrete composite shear wall building with torsional irregularity, Asian Journal of Civil Engineering, 20, 1163–1178.
6-Hussain, M. S., and Tengli, K. S., 2018, Study on torsional effects of irregular buildings under seismic loads, Int J Appl Eng Res, 3, 55–60.
7- Razmkhah, M. H., Kouhestanian, H., Shafaei, J., Pahlavan, H., and Shamekhi Amiri, M., 2021, Probabilistic seismic assessment of moment resisting steel buildings considering soft-story and torsional irregularities, International Journal of Engineering, 34, 2476–2493.
8-Varaee, H., Shishegaran, A., and Ghasemi, M. R., 2021, The life-cycle cost analysis based on probabilistic optimization using a novel algorithm, Journal of Building Engineering, 43, 103032. doi:10.1016/j.jobe.2021.103032.
9-Shishegaran, A., Ghasemi, M. R., and Varaee, H., 2019, Performance of a novel bent-up bars system not interacting with concrete, Front Structure and Civil Engineering, 13, 1301–1315. doi:10.1007/s11709-019-0552-4.
10-Fitrah, R. A., Mazni, D. I., Pratiwi, W., and Jauhari, Z. A., 2021, Seismic assessment of irregularities in steel special moment resisting frame with asymmetric-plan building (case study: Gedung D-Universitas Dharma Andalas), IOP Conf. Ser. Earth Environ. Sci., vol. 708, IOP Publishing; 2021, p. 12007.
11-Noori, F., and Varaee, H., 2022, Nonlinear Seismic Response Approximation Of Steel Moment Frames Using Artificial Neural Networks, Jordan Journal of Civil Engineering, 1-16.
12-Gokdemir, H., Ozbasaran, H., Dogan, M., Unluoglu, E., and Albayrak, U., 2012, Effects of torsional irregularity to structures during earthquakes, Engineering Failure Analysis, 35, 713–717. doi:https://doi.org/10.1016/j.engfailanal.2013.06.028.
13-Akyürek, O., Suksawang, N., and Go, T. H., 2019, Vibration control for torsionally irregular buildings by integrated control system, Engineering Structure, 201, 109775.
14-Ozer, E., Inel, M., and Cayci, B. T., 2022, Seismic behavior of LRB and FPS type isolators considering torsional effects, Structures, 37, 267–283.
15-Bensalah, M. D., Bensaibi, M, and Modaressi, A., 2019, Uncertainties in seismic response of a torsional irregular structure, European Journal of Environmental and Civil Engineering, 23, 488–503.
16-Ghayoumian, G., and Emami, A. R., 2020, A multi-direction pushover procedure for seismic response assessment of low-to-medium-rise modern reinforced concrete buildings with special dual system having torsional irregularity, Structures, 28, 1077–107.
17- Jain, A., and Surana, M., 2022, Floor displacement-based torsional amplification factors for seismic design of acceleration-sensitive non-structural components in torsionally irregular RC buildings, Engineering Structure, 254, 113871.
18- Tzimas, A. S., Skalomenos, K. A., and Beskos, D. E., 2022, A hybrid seismic design method for steel irregular space moment resisting frames, Journal of Earthquale Engineering, 26, 1657–92.
19- Soleimani, R., Hamidi, H., and Khosravi, H., 2022, On advantages of the “Substitute Frame” model for incremental dynamic analysis: Integration of speed and accuracy, Structures, 39, 266–77.
20-Wang, Z., Gao, X., Zhao, Z., Liu, Y., and Meng, Y., 2022, Seismic fragility assessment of traditional air-cooled support structure and air-cooled support energy dissipation structure based on IDA method, Structures, 39, 974–86.
21-Samadi, M., and Jahan, N., 2019, Determining the effective level of outrigger in preventing collapse of tall buildings by IDA with an alternative damage measure, Engineering Structure, 191, 104–16.
22-Contiguglia, C. P., Pelle, A., Briseghella, B., and Nuti, C., 2022, IMPA versus Cloud Analysis and IDA: Different Methods to Evaluate Structural Seismic Fragility, Applied Science, 12, 3687.
23-Dehghani, S., Fathizadeh, S. F., Yang, T. Y., Farsangi, E. N., Vosoughi, A. R., Hajirasouliha, I., et al., 2021, Performance evaluation of curved damper truss moment frames designed using equivalent energy design procedure, Engineering Structure, 226, 111363.
24- Rakicevic, Z., Bogdanovic, A., Farsangi, E. N., and Sivandi-Pour, A., 2021, A hybrid seismic isolation system toward more resilient structures: Shaking table experiment and fragility analysis, Journal of Building Engineering, 38, 102194.
25- Deierlein, G. G., Liel, A. B., Haselton, C. B., and Kircher, C. A., 2008, ATC 63 methodology for evaluating seismic collapse safety of archetype buildings, Struct. Congr. 2008 Crossing Borders, 1–10.
26- Mohebi, B., Chegini, A. H. T., and Miri, A. R. T., 2019, A new damage index for steel MRFs based on incremental dynamic analysis, Journal of Construction Steel Research, 156,137–54. doi:10.1016/j.jcsr.2019.02.005.
27-Mohebi, B., 2019, A new damage index for steel MRFs based on incremental dynamic analysis, Journal of Construction Steel Research, 156, 137–54.
28- Aliakbari, F., Garivani, S., and Shahmari, A., 2020, Determination of torsional irregularity in response spectrum analysis of building structures, Struct Eng Mech, 74, 699–709.
29- Sabet, B., and Talaeitaba, S. B., 2022, IDA analysis of regular and irregular seismically isolated structures in different stories and different seismic categories, Structures, 43, 779–804.
30-Omidian, P., and Saffari, H., 2019, Fragility curves for seismic assessment of reinforced concrete buildings with shape memory alloy in regular, torsional irregularity and extreme torsional irregularity, J Struct Constr Eng, 6, 125–46.
31-Gwalani, P., Singh, Y., and Varum, H., 2019, Comparative seismic fragility of torsionally irregular RC buildings designed using Indian and European codes, SECED 2019 Conf. Earthq. Civ. Eng. Dyn., 2019.