Browsing by Author "Parra Torres, Pablo Fernando"

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    Collapse assessment of a chilean code-conforming reinforced concrete office building
    (Earthquake Engineering Research Institute, 2018) Araya Letelier, Gerardo Andrés; Parra Torres, Pablo Fernando; López-García, Daniela; García Valdés, Óscar Andrés; Candia, G.; Lagos, R.
    Chilean buildings are periodically subjected to earthquakes and their satisfactory performance preventing collapse is widely known. Yet, as a result of the Mw 8.8 2010 Chile earthquake, one reinforced concrete building collapsed and many others were severely damaged, raising concerns about the collapse margin of these structures. Modifications to the Chilean codes were introduced after this earthquake, but Chilean codes are still prescriptive and assessments of the collapse risk of current Chilean buildings is limited. This study evaluates the collapse potential of a code-conforming reinforced concrete office building in Santiago, Chile, whose structural system has a core of two cantilever C-shaped walls surrounded by intermediate moment frames. The architectural layout was designed based on a statistical analysis of the building inventory in Santiago. Incremental dynamic analyses using 45 Chilean earthquakes were performed over a nonlinear model of the building to estimate its collapse fragility, which was combined with a site specific seismic hazard analysis to estimate the mean annual frequency of collapse (γc), and the probability of collapse in 50 years (Pc(50)). Results of γc and Pc(50) were 1.2x10-4 and 0.6%, respectively, and deaggregation of γc is dominated by small to medium earthquake intensities.
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    Comparative seismic collapse assessment of Chilean code-conforming RC dual wall-frame buildings
    (Earthquake Engineering Research Institute, 2022) Gallegos, Marco; Araya Letelier, Gerardo Andres; López-García González, Diego; Parra Torres, Pablo Fernando
    Although the satisfactory performance of Chilean buildings in terms of collapse prevention is widely recognized, there is a need to quantify the actual collapse probability and level of protection provided by current seismic codes. In this study, the collapse potential of code-conforming reinforced concrete dual wall-frame buildings subjected to subduction earthquakes was assessed. A suite of four 16-story archetypes, located at two different seismic zones and on two different soil types, was evaluated considering the latest developments in performance-based earthquake engineering through incremental dynamic analyses of 3D nonlinear models. It was found that the probability of collapse in 50 years is in all cases less than the 1% ASCE 7 target probability, which is consistent with the adequate collapse performance of reinforced concrete buildings that has been observed in recent strong earthquakes (Mw ≥ 8.0) in Chile. It was also observed, however, that the collapse probability is not uniform but strongly influenced by the soil type. This observation suggests that the design response spectra indicated by the Chilean seismic design code for buildings might not correctly account for the influence of the soil type.