Development of Fragility Functions for Brick Masonry Structures Using Damage Data from September 24, 2019, Earthquake in Mirpur, Azad Kashmir

Abstract

This paper presents fragility functions for clay brick unreinforced masonry (URM) buildings that were developed using the data of damage and earthquake intensity by the September 24, 2019, Mirpur, Azad Jammu and Kashmir earthquake. These data were collected through reconnaissance surveys in the affected region. The intensity of the earthquake ranged from V to VII on the Modified Mercalli Intensity scale in the surveyed areas. The damage to clay brick piers of bridges was caused by compression or shear-compression forces applied by the vertical seismic forces. Most of the damaged URM buildings showed in-plane wall cracking with very few cases of out-of-plane wall failure. The damage in these buildings was influenced by both the ground motion's horizontal component and ground motion amplification due to site conditions. The damage types to the URM buildings in the surveyed areas were classified into five damage grades and these data were employed to propose fragility curves for clay brick URM buildings.