Tendencias en la normativa sismorresistente

New trends in seismic codes

The codes of seismic construction have been reviewed during the last few years. The new trends in those codes are focused on the following aspects: ? Introduction of two levels of seismic action, one to determine the functionality of the structure after the seismic action, and other related to a higher return period, to ensure the structural stability after a major seismic event. ? A change in the spectrum shape in other to adapt them to the method of calculus related to the required displacements. Also the way of working with artificial acelerograms has been included in the new codes. ? A new strategy of design based con capacity and the push-over method of analysis are also incorporated in the new version of the modern codes. ? The criteria of the resistance of plastic hinges are also included ? Finally the definition of the Basic principles of seismic design and the necessary details in special zones are also dealt in the new codes. In the present article those aspects, which introduce a more precise analytical behaviour of the structure are described and analyzed.