Page 255 - Çevre Şehir İklim İngilizce - Sayı 4

Ahmet Yakut - Barış Binici

2004, Yakut 2006). At the first phase by evaluating the data collected through
street scanning approach, a cluster which is expected to contain high risk
buildings is determined, these buildings are assessed at the further stages by
using advanced methods with detailed data and finally the most risky buildings
are identified. The first stage is important both in terms of quick detection and
creation of building inventory. In this scope, risk assessment studies should be
started at the scale of cities that are known to have a high earthquake risk in our
country. Cities should be subjected to risk prioritisation studies primarily on the
basis of small areas (such as neighbourhoods) depending on the parameters
such as properties of building stock (number of floors to be quickly identified
by street scanning, utilisation type of ground floors, overhangs etc.), risk of
earthquake (according to earthquake risk map of Türkiye), soil characteristics.
There are many methods specific to our country proposed for this purpose
(Yakut 2004, Sucuoğlu et al. 2007, Yakut 2006, Tezcan et al. 2011). In cases where
detailed street scanning cannot be performed, prioritisation can be made
based on the number of building floors, building location (earthquake hazard),
building age and soil data.
For the buildings which are identified as high risk as a result of first stage,
survey is only made for ground floors by means of simple measurements at
the second stage evaluation. Column placement and dimensions as well as
reinforcement details obtained by non-destructive methods and reinforcement
type and concrete strength are required. Stripping on a few elements is
sufficient to determine the type of reinforcement. Although the most reliable
way to determine concrete strength is to take core sampling, there is a negative
bias against it. If core sampling is not prefered, ultrasound or other non-
destructive methods may be used. The building model is prepared depending
on the ground floor surveys (by copying this floor to the upper floors taking
into account the irregularities in the building). As expressed in detail in the
method proposed further by Binici et al. (Binici et al. 2022), a risk assessment is
performed depending on the average axial load ratio and the interstory drift
ratio. In this method, building survey is drawn up for the ground floor through a
site study and concrete strength is determined. Then, three-dimensional model
of the building is analysed under the vertical loads and service earthquake on
the basis of ground floor survey of the building. The average axial load ratio
obtained from the floors of the building and the corresponding maximum
storey drift ratio are compared with limit values represented by the axial load
ratio in vertical plane, and drift ratio curve in horizontal plane to make an
assessment of the risk condition of the building. In case that the building is
identified as having high risk, it is decided to either reinforce or transform the
it by calculating the rough cost required for reinforcement taking into account

244 The Journal of Environment, Urban and Climate