A STUDY ON FAILURE PATTERN OBSERVED IN MASONRY BUILDINGS DURING 8TH OCTOBER HAZARA-KASHMIR EARTHQUAKE IN PAKISTAN

An earthquake measuring 7.6 on the Richter scale struck Mansehra, Muzaffarabad, Garhi Habib Ullah, Balakot, Bagh, Battagram, Battal, Allai, Naran valley, Neelum valley, Jhelum valley, Islamabad, Lahore etc. on 8th October 2005 at 0852 PST. The epicenter of the earthquake was located near Muzaffrabad. As per official figures, about 74000 are dead, 70000 are injured and 2.5 million families have been displaced. The heaviest damage was observed in Muzaffarabad, Bagh, Allai and Balakot area where entire villages were destroyed. The local traditional stone / block / Brick masonry structures in the area were not designed to withstand the earthquake of such magnitude. This caused considerable damage including major cracks to complete collapse in load bearing members. Unreinforced masonry (URM) structures were damaged commonly due to poor construction practice of load bearing walls. The damage level depended on the distance from surface faulting. Most of the destroyed villages were subjected to the full intensity earthquake vertical and shear motion with negligible attenuation since they were very near to the ruptured zone. This paper attempts to evaluate the behavior of masonry structures based on the type of masonry used in places like Balakot, Bagh, Muzaffarabad and several other places. Quite a few masonry buildings had used earthquake resistant features like lintel bands and corner reinforcements. The cracking and failure patterns of such buildings have also been examined and recommendation for future type of structures will also be proposed in order to educate the local population to adopt suitable earthquake resistant construction practice in the area which could ensure least life as well as property damage.

Keywords:

Seismic activity , Stone/block/brick Unreinforced Masonry , Structural Damages , Crack Pattern