Análisis modal y pushover modal para la evaluación sísmica del edificio patrimonial del Antiguo Colegio Borja mediante una estrategia de modelización en la meso-escala.

Abstract

This thesis evaluates the seismic behavior of the Antiguo Colegio Borja, a heritage unreinforced masonry building, through modal analysis and modal-based nonlinear static (pushover) analysis, using a meso-scale structural model developed in STKO software. The building exhibits an irregular plan geometry, flexible floor and roof systems, and a lack of effective tying elements, conditions that significantly influence its dynamic response and seismic vulnerability. The modal analysis revealed a complex dynamic behavior, characterized by the absence of dominant global modes at low frequencies and the activation of local vibration modes associated with different building blocks, indicating a lack of global structural integrity. The results highlight the strong influence of flexible diaphragms on mass participation and the development of differential deformations among structural components. Modal pushover analyses showed a pronounced directional dependence of the seismic response. While the longitudinal direction exhibits higher strength and a more stable response, the transverse direction is governed by a brittle behavior, with early strength degradation and the activation of out-of-plane failure mechanisms concentrated at wall intersections. Based on the combined interpretation of modal and pushover results, a preliminary seismic vulnerability diagnosis was established, and general strengthening recommendations were proposed, aimed at improving kinematic compatibility and overall structural behavior while respecting the building’s heritage value.