Investigation of Damage to Reinforced Concrete Buildings Due to the 2019 Mirpur Earthquake, Azad Kashmir

This paper presents the results of damage surveys in Mirpur, in the Azad Jammu and Kashmir region of Pakistan, which was affected by a moderate earthquake on September 24, 2019. The epicenter of this earthquake was near the city of Mirpur at a shallow depth of no more than 10 km. Rupture of ground surface was observed in the area close to the epicenter, which can be associated with the release of seismic energy at shallow depths. The ground acceleration recorded at the site close to the epicenter was influenced by the rupture directivity effects. A significantly high vertical component of ground acceleration was observed at a site in close vicinity of the epicenter. Ground-motion amplification was also indicated by the data analysis in the presence of soft soil. A few low- to medium-rise reinforced concrete buildings were severely damaged by the ground shaking. The columns in these buildings experienced compression or shear-compression mode of failure in the presence of high axial compression applied by the vertical seismic forces and/or overturning moment. The longitudinal bars in the columns also buckled due to high axial compression demands coupled with insufficient confinement in the plastic hinging regions.