Behavior and modeling of partially restrained beam-girder connections

Beams in a typical steel framed floor design are assumed to have pinned supports for purposes of design. In reality, the connections between the beams and girders in a steel framed floor system are not pinned. The design bending moments and deflections of the attached beam could be reduced if the true rotational restraint provided by the beam-girder connections could be included in the design. The connection rotational restraint is characterized by the moment-rotation behavior. Consequently, a method for approximating the moment-rotation behavior of the beam-girder connection is required before the beneficial effects of the true connection rotational restraint can be considered in design.

Experimental and analytical research on the moment-rotation behavior of a specific type of beam-girder connection is presented in this dissertation. The primary objective of this research is to develop a component model of the connection that can be used to approximate the moment-rotation behavior. The component model is based on the hypothesis that the connection behavior can be modeled as a combination of the connection component behaviors. The connection components are the fundamental pieces of the connection such as bolts, shear studs, and welds. In general, the component model can be very computationally intensive. Consequently, a secondary objective of this research is to develop a connection model that is simpler to use.

Behavior models for each of the connection components are presented and/or developed. These models are derived from a combination of existing literature, experimental and analytical research, and basic mechanics. Next, a method of combining the component behaviors into a connection model that can be used to approximate the moment-rotation behavior is developed. Results from experimental research on the moment-rotation behavior of the beam-girder connection are then used to verify the model. Finally, a simplified model of the beam-girder connection is developed. This model is based on the same hypothesis as the component model; however, through a combination of assumptions, simplifications, and the results of parametric studies the simplified model becomes far less computationally intensive than the full component model.