Design Moment Resistance of End Plate Connections

Abstract

The end-plate connection, either the flush end-plate or extended end-plate, bolted with high-strength friction fasteners, is one of the moment resistant connections recommended for steel portal frame design, and can be used for rafter to column connection or rafter splice. Current design rules specify that the tension force produced by the bending moment is triangularly distributed among the bolt rows in tension zone, if the end-plate is stiff enough and its deformation is negligible. This chapter proposes a finite element model employed to analyze the bolt-force distribution for the beam to column connections. The beam web and flange are modeled with plate element, while the end plate, bolt heads and nuts are represented by 3D block elements. A number of bar elements are adopted to simulate the bolt shank. The contact elements, which could resist compression but not tension, are used to simulate the interface between the end plate and the column flange. In establishing the finite element model, the bolt pretension is well simulated by temperature action. The connection model is analyzed by loading increment method and the material properties are assumed remaining elastic.