SEISMIC VULNERABILITY ASSESSMENT OF REINFORCED CONCRETE STRUCTURES IN KURDISTAN REGION-IRAQ
Abstract
Earthquakes are one of the most destructive natural disasters that cause losses of life, damage to
infrastructure and economic issues. Therefore, seismic risk assessment is essential for disaster mitigation,
disaster management, and emergency preparedness. Seismic vulnerability is one of the major factors for
evaluating the risk of earthquakes on reinforced concrete (RC) buildings. Seismic vulnerable RC buildings
are buildings located in a seismic region and either designed with an outdated design code or designed
without consideration for seismic activity. In the Kurdistan region of Iraq, most of the existing RC
buildings do not meet the typical current seismic standard requirements as the region was expected as
non-seismic region and followed the Iraqi seismic zone which considered as a low seismic region, therefore
these type of buildings is expected to suffer extensive damage during strong earthquakes. Vulnerable RC
buildings should be assessed in order to prevent future damage and new designed buildings need to meet
such codes. Previous studies, conducted assessment of four to six stories structures in order to evaluate
seismicity and to increase ductility of the evaluated structures based on member size. In this research, an
existing 8-storey RC building, located in Duhok governorate- Kurdistan region of Iraq, is redesigned and
evaluated. SeismoStruct V6.5 software was utilized for the purpose of simulating ductility and detailing
for the existing structure using pushover analysis. The ductility of the existing and the proposed
redesigned buildings then evaluated by obtaining inter-story drift and displacement based on capacity
curve. The original design is further evaluated in terms of reinforcement ratio and detailing by
redesigning the existing building in accordance with the ACI code 318, 2014 and using ETABS software
version 9.7 for analysing. Nonlinear static pushover analysis is used for seismic performance evaluation.
Inelastic static analysis procedures include capacity spectrum method and displacement coefficient
method. The structure is then analyzed to observe the yielding of the members and the adequacy of the
structural strength. The extent of damage experienced by the structure at the target displacement
represents the damage that would be experienced by the building when it is subjected to an earthquake.
As a conclusion, the redesigned structure showed 30% increasing in displacement when loaded in x-
direction based on both ultimate and calculated base shear while the increase in displacement was around
10% when loaded in the y-direction. This displacement increase led into improving the ductility in the
redesigned structure.
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