Application of Discontinuity Layout Optimization to Steel Parts and Steel Connections with a Single Bolt

Abstract

Steel connections are designed with components such as bolts, plates, and welds. The proof of the plates loaded in-plane can be made by hand calculations or more realistic with a nonlinear FE-simulation. As an alternative method, a modified version of the discontinuity layout optimization (DLO) procedure is presented in this paper. The modification takes yield zone mechanisms into account. Furthermore, a compression-only contact was implemented to reproduce the bearing behaviour of bolted connections. The DLO procedure was tested on tensile specimens with and without bolts. The obtained collapse mechanisms and ultimate loads were compared to results from the Eurocode EN 1993-1-8, literature, and FE-simulations. Recommendations to the correct discretization of the tested specimens were given. Especially for the bearing behaviour, modification factors, based on a parameter study, were worked out. The DLO procedure reproduced the collapse loads and mechanisms of all considered cases correctly. The obtained bearing capacities are, in most cases, conservative compared to the Eurocode EN 1993-1-8. The presented research can be seen as the basis for future investigations on more complex problems in steel connections.