Seismic Retrofitting of Unreinforced Masonry School Structures Using External Cable Bracing and Displacement-Based Analysis: A Case Study from Tabriz, Iran

Abstract

Unreinforced masonry (URM) school buildings are particularly vulnerable to seismic events, especially in seismically active regions such as Tabriz, Iran. This study investigates a practical and effective retrofitting technique that employs external cable bracing in conjunction with displacement-based analysis to enhance the seismic resilience of URM school structures. The methodology includes a case study of a representative URM school in Tabriz. Analytical modeling and performance-based assessments demonstrate that optimally placed external cable bracing systems can significantly reduce inter-story drifts and improve overall structural stability. The paper concludes with recommendations for broader implementation in Iran's seismic retrofitting programs. The aim of this research is to analyze the seismic behavior of a three-story school building based on Iranian Code, standard no. 2800 in Tabriz city. The building consists of brick walls and brick slabs with steel I-beams. Seismic loads should be carried by the brick walls and transferred to the strip concrete foundation. The building is calculated according to Iranian Code for type II soil. And the results show that in small displacements, the building behaves elastically or with small cracks (IO). In larger displacements, the building will have larger cracks (LS). In very large displacements, the entire building will behave as cracked (CP).