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

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.