LRFD for Engineered Wood Structures—Connection Behavioral Equations

Abstract

A new design specification for engineered wood structures has been proposed in load and resistance factor design (LRFD) format. This paper provides an overview of the proposed LRFD connections design criteria. The connections design provisions are, in part, calibrated from allowable stress design provisions. Major changes from historic practice, however, result from a change in behavioral equations to a theoretical base for predicting the lateral strength of connections using bolts, screws, and nails. New provisions for axial withdrawal of driven and turned fasteners, as well as combined axial and lateral loading criteria are also proposed. Safety levels were calibrated to historic practice, but some change in design capacity is expected due to format change, conversion to new behavioral equations, and the selection of a calibration point. The LRFD document contains substantial improvement in code clarity, simplification, and structure over the historic allowable stress specification. A clear mechanism for including design with new wood‐based engineering materials is provided.