ABSTRACT
Premature failures of steel beam-to-column moment connections, consisting of welded flange-bolted web detail, shows that conventional beam theory may not be applicable in the vicinity of the connection. In addition, commonly used low notch tough weld metal and poor welding practice are another key reason of brittle fracture of these connections. Through extensive analytical work conducted at The University of Michigan, a new beam-to-column steel moment connection called “free flange connection” was developed based on understanding of the true stress distributions and force flows in the connection region as well as adopting notch tough weld material and improved welding details. Results of five free flange connection specimen tests presented in this paper show excellent ductile behavior with adequate plastic deformation without premature fracture in the connection region.
