Field Investigation of the Performance of Masonry Buildings during the October 23 and November 9, 2011, Van Earthquakes in Turkey

This paper addresses field investigations of the performance of masonry buildings during the October 23 (Erciş) and November 9 (Edremit), 2011, Van earthquakes in Turkey. Erciş and Edremit are villages respectively located 90 km and 18 km from the city of Van in Turkey. Ground accelerations and response spectra for these earthquakes are discussed. A total of 28,000 buildings were damaged or collapsed in the city center and surrounding villages after the Erciş earthquake. This number increased to 35,000 after the Edremit earthquake. Almost all masonry buildings were affected in the region. Most of them in the area were constructed of random or coursed stone walls with no reinforcement to support heavy clay tile roofing over wooden logs. A large number of such buildings were heavily damaged or collapsed. Cracking and failure patterns are examined and interpreted according to current provisions for earthquake resistance of masonry structures. From the field investigations, it is shown that damages had several causes, among them site effect, location and length of the fault, and poor construction quality. In addition, the two earthquakes hit the masonry buildings within 17 days, causing progressive damage. A large number of nonengineered masonry buildings completely collapsed or were heavily damaged. Most of those in the affected area were not designed and constructed in accordance with the Turkish Earthquake Resistant Design Code.