Single Plate Shear Connection Response to Rotation Demands Imposed by Frames Undergoing Cyclic Lateral Displacements

This paper derives the maximum deformation demand placed on bolts in a single plate shear connection in response to rotation demands. The deformation demand is a function of connection neutral axis location. If the rotation demand is large enough to result in the beam bearing on the column, the neutral axis of the connection migrates to the point of bearing. Prior to bearing, the neutral axis will be located within the length of the connection plate. Forty-five data points obtained from three full-scale tests on T-type beam–column specimens connected with a single line of 19 mm (3/4 in.) diameter ASTM A325 bolts (threads included in the shear plane) and 108 mm (4.25 in.) wide 10 mm (3/8 in.) thick plates were used to determine the location of this neutral axis. Three-, four-, and six-bolt connections were tested through 0.06 radians of rotation. The mean location of the neutral axis was 0.63 times the length of the connection plate. The coefficient of variation was 5.9%. Only the six-bolt connection experienced a bolt shear limit state. The calculated ultimate displacement demands on the three A325 bolts that failed were 9.1, 8.9, and 7.9 mm (0.36, 0.35, and 0.31 in.). These values are consistent with the established maximum deformation value for fasteners, 8.6 mm (0.34 in.). Therefore, the equations presented in this paper provide an accurate estimate of the initial connection rotation capacity for single plate shear connections of common size.