El documento nacional de aplicación del Eurocódigo-4. Un guiso de normas

The national application document of Eurocode-4. A code stew

The approval of the structural Eurocodes and their progressive application in Spain, involves the need to modernize the existing national codes, particularly the ones concerning the basic design and actions on structures. The aim of the proposed National Aplication Document (NAD) for Eurocode-4 (EC-4) is to provide the information to enable EC-4 for the design of composite buildings to be used together with the National Code for Loads because Eurocode-1 (EC-1, basis of design and actions on structures) is not yet completely available. For this, it was necessary to make the mentioned spanish code for loads compatible with the probability based methods in EC-1. Starting with an overview of the reliability methods, the approach proposed for the NAD for EC-4, consisting in an adaptation of the nominal values of actions following the spanish codes to the characteristic values of EC-1 is discussed in the paper. Finally, the most important changes introduced by EC-4 and the NAD compared to spanish standard practise are justified. Major changes concern the reduction of partial safety factors for permanent loads, the increase of partial safety factors for the resistance of steel members, imposed loads on garages and vehicle traffic areas as well as wind actions and snow loads.