Ultimate Behavior of Stud Connections within Haunches

AbstractMechanical fasteners are used in composite structures to physically connect steel and concrete components. Composite action is developed primarily by transferring horizontal shear forces through dowel-type connections. Welded headed studs are a conventional dowel-type product for cast-in-place construction. For this reason, the shear response of these types of fasteners has been extensively studied. In some cases, the tensile strength of a stud connection needs careful consideration, such as when evaluating the ultimate capacity of a composite bridge suffering girder damage. Observations from a detailed testing program demonstrated the importance of accurately characterizing the tensile response of a stud connection in determining when the onset of collapse will occur. In this paper, the response of a stud connection within a haunch configuration is characterized under tensile loads to provide essential data for determining the ultimate capacity of a composite bridge having steel girders and a reinforced concrete deck. Empirically derived equations to estimate the tensile strength of a stud connection and its corresponding displacement are proposed based on a data regression analysis. In addition, a method to account for strength reduction due to combined shear and tension forces is introduced using an interaction equation.