Investigating and comparing the seismic behavior of the ConXL Connection with the WUF-W Connection by using fragility curves

Document Type : Research Article


1 Azad university of science and research branch

2 Department of Civil Engineering, Faculty of Civil Engineering, Art and Architecture, Science and Research Branch, Islamic Azad University, Tehran, iran


Steel moment frames are among the structure systems for bearing gravity and lateral loads, which are more common in high-rise structures due to their lower weight than reinforced concrete moment frames. The ductility capacity of steel moment frames depends on the types of their connections, hence the moment connections are particularly important. Nowadays, in the American Steel Codes and the Iranian National Building Regulations, models have been introduced as Prequalified Connections. The ConXL modern moment connection is one of these connections and in this research that is under study. This connection is designed to create a cost-effective and resistant moment frame that allows quick installation of the frame by eliminating workshop welding. Also, WUF-W, which is known as a rigid connection in domestic codes, is a conventional connection in construction and can be a suitable reference for comparison with ConXL, which is less known in terms of seismic behavior. To do this comparison, fragility curves, which are suitable tools for determining the probability of vulnerability, are used. For this purpose, fragility curves are determined for both ConXL and WUF-W connections. The criterion of this comparison is the performance levels of IO and CP in the fragility curves of joints in a special two-dimensional bending frame. Finally, after comparing the seismic behavior of the two mentioned connections and expressing the more favorable performance and ease of implementation, it can be concluded that the modern ConXL Connection is a more suitable option for special moment frames.


Main Subjects

[1] H. Negaresh, Application of geomorphology in locating cities and its consequences, Geographical Research and Development Conference,  (2003, In Persian).
[2] S. Tavousi, Jafari, Mohadeseh., Evaluation of fragility curves of steel structures with connection with reduced beam cross section, Third International Congress of Contemporary Civil Engineering, Architecture and Urban Planning,  (2009, In Persian).
[3] A.A. Rezaei, Hosseini, Mirhamid., Probabilistic performance comparison of End Plate flange connection with incremental dynamic analysis of IDA 6th National Conference on Applied Research in Civil Engineering, Architecture and Urban Management,  (2010, In Persian).
[4] F. Shahidi, Rezaeian, Alireza., Evaluation of non-linear cyclic behavior of CONXL moment connection with different detail in the column and optimizing the arrangement of bolts, Modares Civil Engineering journal,  (2014, In Persian).
[5] A. Rezaeian, Shahidi, Farhood, Seismic behavior of ConXL rigid connection in box-columns not filled with concrete, Journal of Constructional Steel Research, 97 (2014) 79-104.
[6] C. Yang, Yang, J. F., Su, M. Z., & Liu, C. Z., Numerical study on seismic behaviours of ConXL biaxial moment connection, Journal of Constructional Steel Research, 121 (2016) 185-201.
[7] M. Moghimi, Keyhani, Ali., Investigation and improvement of seismic performance of ConXL moment rigid connection for common steel sections in Iran, Shahroud University of Technology, 2015 (In Persian).
[8] ANSI/AISC358, Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications, in, American Institute of Steel Construction, Chicago, 2010.
[9] ANSI/AISC-341, Seismic Provisions for Structural Steel Buildings, in, American Institute of Steel Construction, Chicago, 2010.
[10] M. Bin Md. Tahir, Faridmehr, Iman, Seismic and progressive collapse assessment of SidePlate moment connection system, Structural Engineering and Mechanics, 54 (2015) 35-54.
[11] FEMA-356, Prestandard and Commentary for the Seismic Rehabilitation of Buildings, in, Federal Emergency Management Agency, Washington DC, 2000.
[12] A. Cornell, Shome, N., Earthquakes, Records and Nonlinear MDOF Responses, Reliability of Marine Structures Program Department of Civil Engineering, Stanford University,  (1997).
[13] NEHRP, NIST GCR 17-917-46v2, NEHRP Guidelines for Nonlinear Structural Analysis for Design of Buildings, Applied Technology Council, 2017.
[14] R. Baron-Corverra, Andrei M. Reinhorn, Global Spectral Evaluation of Seismic Fragility of Structures, in:  Seventh National Conference on Earthquake Engineering (7NCEE), the US, 2002.