Análisis de Desempeño Sísmico y Estados de Daño del ‘Antiguo Colegio Borja’

Abstract

This research evaluates the seismic performance and damage states of the Antiguo Colegio Borja (ACB) in Cuenca, a heritage unreinforced masonry (URM) building. The study is based on the application of the Capacity Spectrum Method (CSM), following ATC-40 and FEMA 440 guidelines, and utilizes 3DMacro software for non-linear response modeling via discrete macro-elements. Structural scenarios were analyzed, including the original configuration and a proposed retrofitting of horizontal diaphragms using double timber planking and Cross Laminated Timber (CLT) panels. Modal analysis results revealed that the flexibility of the original diaphragms generated uncoupled vibration modes, limiting the structure's global response. The implementation of stiffening techniques increased global stiffness, promoting "box-type behavior" and allowing for more efficient load transfer to the load-bearing walls. Through the Capacity Spectrum Method, performance points were determined, demonstrating that the building enters the inelastic range under design earthquakes. The predominant collapse mechanisms identified consist of diagonal shear cracking in the lower-level walls. Finally, fragility curve analysis confirms that retrofitting improves load-bearing capacity; however, the masonry retains an intrinsic brittleness that necessitates the evaluation of comprehensive interventions to guarantee global stability against severe seismic events.