Appropriate spring stiffness models for the end support of bolted angle compression members

Preliminary numerical and experimental investigations by the authors have highlighted the fact that the stiffness of the rotational restraints at the gusset plates near the ends of members are crucial for the prediction of the compression member capacities of bolted angles. Consequently, analytical models for estimating appropriate spring stiffness values have been developed for several practical applications in buildings and two‐bolt connections at both ends of a member. The connection details investigated comprise a simply fixed gusset plate, a connection to the flange of an I‐shaped section and a connection to the web of an I‐shaped section via a gusset plate. In this paper, the formulae developed are presented alongside the detailed background to their derivation. The stiffness values formulated can in future be used to improve the accuracy of the prediction of the compression member capacities of single steel angles with bolted end connections.