Structural Performance of Isolated Steel Beam-to-Column Connection

The present study attempts to determine the main characteristics of a new proposed steel connection retrofitted by an elastomeric isolator. Its stiffness, strength, and ductility are investigated. The elastomeric isolators were designed according to the Japanese Society of Base Isolation with the aim of improving the energy dissipation of the connection. Experimental tests were conducted to evaluate the moment rotation (M-θ) curve of the proposed connection as well as of fully-rigid (SidePlate) and semi-rigid (flush end-plate) connections. The behaviour of beams with flexible and fixed-end connections was also studied by classical methods of analysis. The initial stiffness and classification index of the connections were identified by an analytical calculation in compliance with the methods suggested by Eurocode 3 Part 1-8 and ANSI/AISC 360-10. The results confirmed that the new proposed connection can be classified as a flexible connection in terms of its initial stiffness; however, it developed 90% of the plastic moment capacity of a connected beam. Besides, it showed that the isolated connection did address the AISC drift angle capacity requirement of for a special moment frame (SMF).