Comparative study of seismic spectra of great magnitude occurred in Chile between 2012 to 2022 and the design spectra of seismic standard NCH433

Abstract

In this document, a study of the spectra of large-magnitude seismic records that occurred in Chile between 2012 and 2022 is presented, comparing them with the design spectra of NCh433 and D. S 61. For this, seismic records greater than Mw = 6 have been used, with different depths to the hypocenter and with different types of soil. The catastrophes caused by earthquakes with magnitudes greater than Mw = 6 in the last decade in seismic zones (Turkey and Syria, 2023; Pakistan, 2013; Iran, 2014; Ecuador, 2016 or, Mexico, 2017; among others), have called into question the requirements structural aspects of earthquake-resistant standards in the world. That is why this work aims to demonstrate that highly seismic areas such as Chile, prone to having earthquakes with magnitudes greater than Mw = 6, have seismic-resistant regulations updated to the existing reality. The aim is to demonstrate whether the design spectra of the Standard have been sufficiently representative to determine the calculation accelerations used in the structural design of buildings. It is concluded that many of the spectral accelerations of the records that occurred in Chile exceed those of the design spectrum of the Standard, especially for short periods. Finally, in this research, new design spectra composed of 3 intervals (the 2nd interval is a plateau) are proposed that are more adjusted to the existing seismic reality in Chile during the last decade, considering the type of soil (A-D) existing in the Code (D.S 61).