Contribución de registros espectro compatibles para diseño de edificaciones ubicadas sobre suelos blandos en la zona urbana de la ciudad de Machala

Abstract

This project describes the methodology and criteria used for the search and selection of accelerograms in various databases, such as PEER (Pacific Earthquake Engineering Research Center), IGEPN (Instituto Geofísico de la Escuela Politécnica Nacional), CISMID (Centro de Observación para la Ingeniería Sísmica), and CSN (Centro Sismológico Nacional de la Universidad de Chile). The main objective is to make the response spectrum of these accelerograms resemble the elastic design spectrum for the city of Machala, which corresponds to a return period of 475 years.For this purpose, rigorously selected thirteen pairs of accelerograms representing the horizontal components of the records from a base of seventy-seven records. These accelerograms were taken from earthquakes recorded by accelerometer stations in countries such as Ecuador, Peru, and Chile. The selection criteria comply with the standards established by ASCE-7 (American Society of Civil Engineers) and FEMA 450 (Federal Emergency Management Agency). The criteria include considerations such as the source mechanism, earthquake magnitude, and site soil conditions, which were classified based on the Fourier amplitude of each accelerogram to determine its dominant period. A filtering and correction process was applied to the accelerograms to perform spectral adjustment. This adjustment was carried out in the period range from 0.08 to 3.3 seconds. It aimed to modify the spectral content of the accelerograms so that the average of the spectra in the maximum direction does not deviate more than 10% above or below the target spectrum. This adjustment was verified using the Square Root of the Sum of the Squares (SRSS) method.