Analysis of three-dimensional frames with flexible beam–column connections

Abstract

A procedure is presented for analyzing three-dimensional rectangular steel frames that incorporate any of five commonly used beam–column connection types. A method is described for expressing the moment–rotation behavior of all connections of a given type (for example all end plate connections) in terms of a single standardized Ramberg–Osgood function.The method involves an examination of experimental information on the moment–rotation behavior of a given connection type to determine the influence of various size parameters, such as end plate thickness. It has been used to generate standardized moment–rotation functions for five common connection types and the functions are presented.An iterative, successive approximation structural analysis procedure is described in which repeated approximations are made to assumed stiffness characteristics of all connections in the structure. When the appropriate connection stiffnesses have been determined, a single linear analysis is performed to determine the correct structural displacements and internal forces. Thus, the nonlinear behavior of the connections is properly accounted for. Examples are presented to demonstrate the influence of connection deformation on structural displacements and internal forces.