IES VAConnect User's Guide
Double Angle Bolted Design
Double Angle Bolted connections are used to connect steel beams to column or girders. VAConnect is capable of designing these connections to support coped beams and to resist both shear and axial loads.
Double Angle Bolted connections are checked per the AISC Steel Construction Manual Part 10 (16th Edition) and AISC 360-22 design specifications. In accordance with AISC part 10, the eccentricity on the supported side of the double-angle connection (i.e. the beam side) is neglected when a single vertical row of bolts through the beam does not exceed a distance of 3 inches from the face of the support. When this condition is not met, VAConnect accounts for eccentricity using the Instantaneous Center of Rotation method to determine the eccentric bolt group capacity (shear, bearing, and tearout) at the beam side of the double angle and at the web of the beam. The “C” coefficients for eccentrically loaded bolt groups are included in the detailed reports.
VAConnect assumes that the pin (which allows for rotational ductility) occurs at the face of the support. Therefore, eccentricity at the faying surface of the double angles and the support is not considered. While VAConnect limits the maximum thickness of the double angle connection to 5/8 inches to allow for flexibility in the connection, the workable gage of the bolts to the support is not specifically checked in the program.
VAConnect allows double angle bolted connections to be designed for combined axial and shear forces neglecting eccentricity according to the AISC Steel Construction Manual Part 12 (16th Edition) and closely following Example II.A-1B of the AISC Design Examples Version 16.0. Bolt shear and tension interaction (including prying) and biaxial block shear interaction are both accounted for according to the example.
VAConnect also allows double angle bolted connections to be designed for combined eccentric shear force (force in-plane and parallel to the bolt line in the beam's web) and axial force (force in-plane and perpendicular to the bolt line in the beam's web). Since the AISC Design Examples Version 16.0 does not explicitly address this combined force condition for all bolted double angles, VAConnect uses the methods outlined in Example II.A-19B (Extended single-plate connection subject to axial and shear loading) to design the legs of the angles that are connected to the beam for combined eccentric shear and axial force. Specifically, the interaction of the shear, axial, and flexural loads are considered for both the yielding/buckling limit state and for the rupture limit state. The program’s detailed reports clearly document how the various limit states are checked.
Beams coped at one or both flanges are checked per the AISC Steel Construction Manual Part 9 (16th Edition) and AISC 360-22 design specifications. The 16th Edition of the AISC Steel Construction Manual does not explicitly address how to design coped beams for combined shear and axial loading. Therefore, VAConnect uses the same methodology as the shear tab in Part 12 of the AISC Steel Construction Manual (16th Edition) and in Example II.A-19B of the AISC Design Examples Version 16.0 to account for the interaction of the shear, axial, and flexural loads for both the yielding/buckling and the rupture cases of the coped beam. Furthermore, the interaction for biaxial block shear on the coped beam is accounted for according to the aforementioned example.
VAConnect checks the following limit states for Double Angle Bolted Connections (refer to the program’s detailed reports for specific code references):
The figure below shows the possible block shear failure methods that VAConnect checks for the double angles. In addition to checking each case (a through d) independently, the interaction for block shear failure from combined shear and tension is considered. While combined block shear only needs to be checked for case a and case b in the figure below, VAConnect conservatively uses the lowest capacity from case b through case d for tension to combine with case a for shear. VAConnect checks the appropriate block shear failure methods and block shear interaction as needed for the web according to the beam's coped condition.
