Seismic Risk Assessment of Masonry Buildings in Istanbul for Effective Risk Mitigation

Abstract

Unreinforced and non-engineered masonry buildings are highly vulnerable to seismic hazard and constitute a significant percentage of earthquake losses, including both casualties and economic losses. This study presents an engineering application on seismic safety assessment of unreinforced masonry (URM) buildings in Istanbul, Turkey, a metropolitan city under very high seismic risk. Nearly 20,000 masonry buildings were examined through a two-stage assessment procedure in order to identify the addresses of those buildings which are under high seismic risk. Furthermore, the obtained database can be employed in the preparation of an earthquake mitigation strategy for the expected major earthquake in Istanbul. In the first-stage evaluation, buildings are examined visually from the street by considering their basic structural parameters and they are ranked within a priority list in terms of the calculated seismic risk. Next, the buildings identified with higher risk are evaluated in the second stage by using a more detailed procedure. The developed procedure is both an optimal and a practical tool in the seismic risk assessment of large masonry building stocks in a short period of time with limited resources.

Evaluation of Seismic Vulnerability of Buildings Based on Damage Survey Data from the 2007 Pisco, Peru Earthquake

“…Comparisonoffragilitycurvesobtainedinthisstudyfor buildings in Pisco with those obtained by Tarque et al [9] for buildings in Cusco. ings in HAZUS and URM (unreinforced masonry) in Istanbul (developed by Erberik [10,11]), as shown in Fig. 12.…”

“…Fragility curves are widely used to predict building damage due to earthquakes. Fragility curves have been developed in other studies from statistical analyses of actual damage data [5][6][7] and analyses of the seismic capacity of buildings [8][9][10][11]. To reflect regional seismic characteristics appropriately in damage assessment, it is necessary to confirm the validity of the damage evaluation methodology used.…”

Investigation of materials and damage sources of local masonry structures in Turkey

“…While adobe elements' compressive strength is quite low, that of an average sample can reach up to 2 MPa [7]. Allowable shear strength for adobe walls is 0.05 MPa and allowable compressive strength for adobe blocks is 1.1 MPa [8].…”

“…Some brick wall examples are presented in Figure 3. While solid clay brick's compressive strength is 6 MPa, hollow brick's compressive strength is 4 MPa [7]. Examples of brick wall.…”

“…), baked clay, and mineral aggregates, which expand at high temperatures and suddenly cool afterwards, are used as aggregates [13]. The average compressive strength of briquettes is 2 MPa [7]. The modulus of elasticity of a briquette wall is 2500 MPa [14].…”