Overview of actions in EN 1991 and EN 1998 for BRIDGE DESIGN

摘要

The constituent parts of BS EN 1991 (Eurocode 1) comprise: BS EN 1991-1-1 Densities, self-weight and imposed loads BS EN 1991-1-2 Actions on structures exposed to fire BS EN 1991-1-3 Snow Loads BS EN 1991-1-4 Wind actions BS EN 1991-1-5 Thermal actions BS EN 1991-1-6 Actions during execution BS EN 1991-1-7 Accidental actions BS EN 1991-2 Traffic loads on bridges BS EN 1991-3 Actions induced by cranes and machinery BS EN 1991-4 Actions in silos and tanks The coverage of this conference is confined to those parts of BS EN 1991 that are relevant to bridges. These parts are highlighted bold in the above list. Separate papers describing the background to the UK National Annex (NA) and, where relevant, the associated Published Documents (PDs), are included for BS EN 1991-1-4, BS EN 1991-1-5, BS EN 1991-1-7 and BS EN 1991-2. The coverage of this paper is primarily concerned with differences in the treatment of actions (loads) in BS EN 1991 compared to previous design practice (BS 5400-2 and HA DMRB BD 37 for example). Also covered is a brief overview of the way in which seismic actions are derived using BS EN 1998 for UK bridges. Since seismic actions are not covered specifically in BS 5400-2 and HA DMRB BD 37, these requirements cover new ground. More detailed discussion of earthquake design guidance for UK bridges is included in a separate paper (paper 1 -3/6, Booth et al 2010). This paper will highlight the issues that will need to be addressed in future in the light of experience gained from implementation of the Eurocodes.