The static method of seismic analysis proposed by the Italian code of practice can lead to non- conservative design. This may happen when the rigorous value of the fundamental period of the structure is adopted instead of the approximate one given by the code.The present paper shows that in the presence of eccentricity between the stiffness center and the mass center of the building floors, the static method can under-evaluate the maximum seismic effects by more than 25%. Appropriate changes in the code should be introduced in order to bring the static method to the safe side. Some possible improvements are discusses in the present paper.
