Standardized flexible end plate connections for steel beams

Abstract

A flexible end plate connection consists of a plate fastened to both sides of the web of a beam by fillet welds. Bolted field connections are used. The connection should transmit vertical shear and allow beam end rotations to occur without the development of significant moments. It is common practice to evaluate the shear capacity of these connections neglecting the presence of secondary forces, which can develop when the connection rotates.Existing analytical models of the moment–rotation behaviour correlate well with test results. These models consider both the flexural and membrane response of the connection in the upper tensile zone and use an empirical relationship to predict the force developed in the lower compression zone. In some tests undesirable impairment of connection flexiblity occurred when the bottom flange of the beam contacted the support.A limit states design model has been developed, which better predicts the moment–rotation characteristics of the connection and which also predicts the reduced vertical shear capacity of the connection due to secondary forces. Consideration of the secondary forces results in connections being designed with more consistent safety levels.An interactive computer program has been developed to design flexible end plate connections using this model. The program is attached to a data file containing the geometric properties of all standard steel flexural shapes available in North America. By specifying any of these shapes along with the desired material properties, loading conditions, connection geometry, and associated connection component costs, a designer can use the program to rapidly prepare customized connection designs or design tables. Key words: beams, connection, end plate, flexible, interactive computer program, joints, limit states design method, plastic deformation, shear strength, steel structures, structural analysis, structural design.