Research Report Rose 2007/03
Istanbul is one of the most obviously hazardous regions in the world and is expecting an earthquake along the fault which is just tens of kilometres away.
Istanbul is one of the most obviously hazardous regions in the world and is expecting an earthquake along the fault which is just tens of kilometres away. Assessment of the seismic vulnerability of the building stock in this region, Northern Marmara of Turkey, is of growing importance since such information is needed for reliable estimation of the losses that possible future earthquakes are likely to induce. The outcome of such loss assessment exercises can be used in planning of urban/regional-scale earthquake protection strategies; this is a priority in Turkey, particularly following the destructive earthquakes of 1999. Considering the size of the building inventory, it is not easy to determine the structural properties and characteristics of the building stock in Istanbul and its surrounding area. In this report, geometrical, functional and material properties of the building stock in the northern Marmara region, particularly around Istanbul, have been investigated and evaluated for use in loss estimation models and other types of statistic- or probability-based studies. In order to do that, the existing stock has been classified as good or poor buildings, dual (frame-wall) or frame structures, and emergent or embedded beam systems. In addition to the statistical parameters such as mean values, standard deviations etc., probability density functions (PDF) and their goodness-of-fit have also been investigated for all types of parameters. Functionalities such as purpose of use and floor area properties have been defined. A clear comparison between the recent and the former legal regulations of construction has been included in the report in order to discuss the evolution of the vulnerability of the stock. Material properties have also been discussed in terms of the concrete and the steel properties of existing and recently constructed buildings. Finally, the financial effects of retrofitting operations and damage repair have been investigated. Damage ratios are calculated to aid mean damage ratio estimations.