Comprehensive Methodology for Assessing Structural Response to Probable Seismic Motions: Application to Guatemala City

This study presents a comprehensive methodological framework that encompasses all stages required to evaluate the structural response to potential seismic motions. The proposed approach involves the estimation of seismic hazard at the site of interest, the disaggregation and definition of control earthquakes, the characterization of local site effects, the assessment of possible resonance phenomena, and the comparison between response spectra derived from probable seismic scenarios and the design spectra of the buildings, leading to conclusions regarding structural safety. The methodology integrates instrumental measurements of soil and building vibration periods with analytical procedures to define response spectra consistent with expected seismic scenarios. It was applied to buildings of special importance located in Guatemala City, particularly within the University of San Carlos of Guatemala (USAC) campus, with the aim of evaluating their structural safety and developing retrofitting criteria when necessary. The implementation began with a probabilistic seismic hazard analysis (PSHA) to identify control earthquakes that make the largest contribution to hazard for a 475-year return period, followed by the estimation of rock response spectra. A seismic microzonation study was then conducted to characterize local site conditions. Instrumental vibration measurements of the soil and structures were obtained, and a soil–structure interaction analysis was carried out to evaluate potential resonance effects. The results showed no evidence of resonance. Finally, soil response spectra derived from the control earthquakes were compared with the design spectra defined by the AGIES 2024 structural safety standards. The results confirmed that the design spectra adequately envelope the computed response spectra for all soil–structure combinations. The proposed methodology is replicable and can be used to assess the seismic design adequacy of other buildings, providing a rational basis for retrofitting decisions when design spectra do not fully encompass the expected seismic response.