Seismic-Resistant Design Regulations for Structures, Earthquake and Experimental Results Lessons

The Mexico City earthquakes of September 19, 1985, and September 19, 2017, showed that the seismic requirements for these earthquakes exceeded those specified in the Mexico City building code. This study illustrates limitations in current procedures for the seismic analysis of structures. The Uncertainties in the assessment of seismic design requirements and limitations in the seismic analysis of structural systems indicate that the lateral strength specified in building codes is not sufficient and that structures must have lateral deformation capacity. It follows that structural systems with low or intermediate ductility, such as those allowed in the Mexico City Building Code (MCBC, 2017), would not be desirable for resisting strong earthquakes. The last part of this work shows computed story drifts in buildings with different structural systems, either based on frames or using structural walls. This study compares story drifts in these structural systems for both using the seismic demands specified by MCBC 2017 and for the seismic demands corresponding to the September 19, 2017, earthquake in Mexico City. The results for these story drifts show the importance of rigid structural systems for reducing story drift demands, not only for avoiding collapse in strong earthquakes but also for significantly reducing building damage.