Steel Buildings in Europe

Part 5: Joint Design 5 – 1 1 INTRODUCTION 1.1 About this design guide This technical guide is for designing simple joints (nominally pinned) for use in braced multi-storey buildings, designed according to the Eurocodes. Design procedures are provided for:  Beam-to-beam and beam-to-column joints  Partial depth flexible end plates (also known as header plates)  Fin plates  Double angle web cleats  Column splices  Column bases The design procedures start with recommended detailing rules (joint geometry) required to ensure ductile behaviour, followed by the checks for each stage of the load transition through the complete joint including welds, plates, bolts and the section webs or flanges as appropriate. Whilst the Eurocodes establish a common framework for structural calculations across Europe, structural safety remains each country’s responsibility. For this reason there are some parameters, called National Determined Parameters (NDP), which each country can decide upon. These are given in the National Annex (NA) documents, which complement the core Eurocodes. However the Eurocode gives some recommendations as to what value each NDP should take. In designing the structure the NDP should be taken from the NA from the country where the structure is to be built. In this publication the recommended values given in the Eurocode have been adopted in the worked examples. This publication is complemented by a spreadsheet design tool which allows for NDP for a range of countries. The spreadsheet covers all the joint types included in this publication and can be used in various languages. 1.2 Joint behaviour Normal practice in simple construction is for beams to be designed as simply supported and for columns to be designed for both the axial compression and, where appropriate, a nominal moment from the beam end connections. In order to ensure that the structure behaves appropriately it is necessary to provide ‘simple’ connections (‘nominally pinned’ joints) as defined in EN 1993-1-8, § 5.1.1 [1] , in which the joint may be assumed not to transfer bending moments. In other words, the joints possess sufficient rotation capacity and sufficient ductility.