Proposing loading protocol for beam to column steel moment connection in Iran for near-field earthquakes

Document Type : Original Research

Authors
M. Ghassemieh 1
E. Alizahi 2
S. R. Mirghaderi 3
1 School of Civil EngineeringCollege of EngineeringUniversity of Tehran
2 School of Civil EngineeringUniversity of Tehran
3 School of Civil Engineering - University of Tehran
DOI: 10.22034/22.3.37
Abstract
Due to the relatively high use of steel buildings in Iran and the importance of rigid steel beam-to-column connections, which are among the vital components in this type of buildings, the need to better understand the behavior of these connections against earthquakes has been noted. Also due to the special characteristics of the near-field earthquakes, which is different than far-field earthquakes and it has its own characteristics; and the fact that some catastrophic earthquakes occurred in Iran, such as the Bam earthquake (2003) and the Tabas earthquake (1978) had the characteristics of the near-field earthquakes, which can show the importance of the near-field ground motions; the purpose of this study was to propose a loading protocol for special steel moment- resisting frames under near-field earthquakes for Iran. Therefore, first, by examining the earthquakes that have occurred in Iran during several years, near-field earthquakes have been selected. Steel buildings of 3, 5, 7, 9, 12 and 20 floors were designed and analyzed according to the rules and regulations of Iran, then for each of the designed steel buildings a critical frame was determined; the values of the scale factors are also specified. After performing nonlinear­ time‐history analysis and applying the proposed near-field ground motions to all of the critical frames, inter-story drift angles for all frames was obtained and compared. The third floor of the 3-story critical frame was selected as the critical floor; which is a story whose results will be used to construct a loading protocol; The basic rainflow counting and simplified rainflow counting were performed for the critical inter-story drift angles results; The proposed loading protocol are derived based on the MCE-level seismic hazard and 84th percentile values of key seismic demand parameters. These parameters are number of damaging cycles, maximum inter-story drift, sum of inter-story drift range, inter-story drift range and residual inter-story. The rationality of the proposed loading protocol was justified by showing the cumulative distribution function. The proposed loading protocol has 23 damage half-cycles, including 3 pulse half-cycles with inter-story drift ranges of 0.060, 0.100 and 0.078 radians; which are calculated by the basic rainflow counting method. The maximum inter-story drift was obtained 0.065 radians. In the final half cycle, the mean value is the same as the residual inter-story drift of 0.03 radians. Also, the sum of the inter-story drift ranges is equal to 0.684 radians. The proposed loading protocol was compared with the SAC near-field earthquake protocol, the maximum inter-story drifts in the proposed protocol is 0.065 radians and in the SAC protocol is 0.06 radians. Furthermore the pulse cycles in the proposed protocol have inter-story drift ranges equal to 0.060, 0.100 and 0.078 radians; while the three pulse half-cycles at the beginning of the SAC loading protocol have inter-story drifts of 0.08, 0.05 and 0.04; respectively. Therefore, the proposed loading protocol has a higher inter-story drift and stronger pulse cycles than the SAC near-field earthquake protocol; but the total number of cycles defined in the SAC protocol is greater than the proposed protocol.

Keywords

Subjects

[1] Bravo, Miguel A., and Ricardo A. Herrera. 2014 Performance under cyclic load of built-up T-stubs for double T moment connections. Journal of Constructional Steel Research, 103, 117-130.
[2] Malley, James O. 1998 SAC steel project: Summary of phase 1 testing investigation results. Engineering structures, 20(4-6), 300-309.
[3] Krawinkler, Helmut. 2009 Loading histories for cyclic tests in support of performance assessment of structural components. In The 3rd international conference on advances in experimental structural engineering, San Francisco.
[4] Maison, Bruce F., and Matthew S. Speicher. 2016 Loading Protocols for ASCE 41 Backbone Curves. Earthquake Spectra, 32(4), 2513-2532.
[5] ATC-24. 1992 Guidelines for Cyclic Seismic Testing of Components of Steel Structures for Buildings. Applied Technology Council, Redwood City, CA, Report No. ATC-24.
[6] Clark, P., Frank, K., Krawinkler, H., and Shaw, R. 1997 Protocol for Fabrication, Inspection,Testing, and Documentation of Beam-Column Connection Tests and Other Experimental Specimens. SAC Steel Project Background Document, Report No. SAC/BD-97/02.
[7] Krawinkler, H., Gupta, A., Medina, R., and Luco, N. 2000 Development of Loading Histories for Testing of Steel Beam-to-Column Assemblies. SAC Background, Report No. SAC/BD-00/10.
[8] FEMA. 2007 Interim Protocols for Determining Seismic Performance Characteristics of Structural and Nonstructural Components Through Laboratory Testing. FEMA 461 Draft document, Federal Emergency Management Agency.
[9] Ghassemieh, M. and Hasani sokhtesaraei, M. 2016 Effect of Loading Protocol on the Steel Moment Connections in Iran. Modares Civil Engineering Journal (M.C.E.J), 16(4), 213-223. (In Persian).
[10] Fang, C., Ping, Y., & Chen, Y. 2020 Loading protocols for experimental seismic qualification of members in conventional and emerging steel frames. Earthquake Engineering & Structural Dynamics, 49(2), 155-174.
[11] Ghassemieh, M., & Rahimzadeh, A. 2018 Impact of loading protocol on the performance of the steel moment frame connections. Journal of Rehabilitation in Civil Engineering, 6(2), 115-138.
[12] Ghassemieh, M., Hassani Sokhtesaraei, M., & Mirghaderi, S. R. 2021 The Behavior of Welded Moment Connections in Box-Columns and Investigating Applied Demands for Different Cyclic Loading Protocols. International Journal of Steel Structures, 21(2), 455-474.
[13] Ghassemieh, M., Hassani S, M., & Mirghaderi, S. R. 2021 Cyclic dependency assessment of RBS moment connection in box-column. Journal of Constructional Steel Research, 177, 106472.
[14] Alavi, B., & Krawinkler, H. 2000 Consideration of near-fault ground motion effects in seismic design. In Proceedings of the 12th World Conference on Earthquake Engineering.
[15] Li, S., & Xie, L. L. 2007 Progress and trend on near-field problems in civil engineering. Acta Seismologica Sinica, 20(1), 105-114.
[16] Stewart J P, Chiou S J, Bray J D, et al. 2001 Ground motion evaluation procedures for performance-based design [R]. California, Pacific Earthquake Engineering Research Center, University of California, Berkeley, Report No. 01-09, 63-67.
[17] Khansefid, A., Bakhshi, A., & Ansari, A. 2019 Development of declustered processed earthquake accelerogram database for the Iranian Plateau: including near-field record categorization. Journal of Seismology, 23(4), 869-888.
[18] Shahi, S. K., & Baker, J. W. 2014 An efficient algorithm to identify strong‐velocity pulses in multicomponent ground motions. Bulletin of the Seismological Society of America, 104(5), 2456-2466.
[19] BHRC. 2014 Iranian code of practice for seismic resistant design of buildings. Tehran, Building and Housing Research Center, Standard No.2800. (In Persian).
[20] ASCE. 2013 Minimum design loads for buildings and other structures. American Society of Civil Engineers.
[21] Shahi, S. K., & Baker, J. W. 2011 An empirically calibrated framework for including the effects of near-fault directivity in probabilistic seismic hazard analysis. Bulletin of the Seismological Society of America, 101(2), 742-755.
[22] Mazzoni, S., McKenna, F., Scott, M. H., & Fenves, G. L. 2006 OpenSees command language manual. Pacific Earthquake Engineering Research (PEER) Center, 264, 137-158.
[23] Hassani sokhtesaraei, M. 2013 Effect of loading protocols on structural steel moment connections in Iran, M.sc. Thesis, University of Tehran, Tehran. (In Persian).
[24] Zhou, M., Jiang, L., Chen, S., Cardoso, R. P., & Usmani, A. 2020 Remaining fire resistance of steel frames following a moderate earthquake–A case study. Journal of Constructional Steel Research, 164, 105754.
[25] National Institute of Building Sciences Council, Building Seismic Safety Council. 2012 FEMA P-751: 2009 NEHRP Recommended Seismic Provisions, Design Examples.
[26] Matsuishi, M., & Endo, T. 1968 Fatigue of Metals Subjected to Varying Stress.
Proceedings of the Kyushu Branch of Japan Society of Mechanics Engineering, Fukuoka,
Japan.
[27] ASTM. 2005 Standard Practices for Cycle Counting in Fatigue Analysis. ASTM
International.
Modares Civil Engineering journal
Volume 22, Issue 3
May and June 2022
Pages 37-51