# Geotechnical and Structural Damages Caused by the 2023 Kahramanmaras Earthqu in Golbasi (Adyaman)
## 6 Structural Findings  
### Damages Observed in Reinforced Concrete Structures  
Figure 14 shows examples of collapsed reinforced concrete structures with an inadequate frame made of reinforced concrete and plastic hinges produced mostly at the bottom ends of the ground floor columns.  
The main reasons for this are the inadequate reinforced concrete frame, the weak column-beam connection, the column dimensions being smaller than the beam dimensions, and the building floors piling up on top of each other and collapsing altogether. Examples of this type of damage, called pancake, are shown in Figure 15.  
Partial and complete collapses occurred on the ground floors due to stiffness differences between floors. Especially in buildings where the ground floors are used as workplaces and the upper floors are used as residences, the number of infill walls varies between floors. Examples of partial or total collapse that occurred on the ground floors as a result of this are shown in Figure 16.  
Figure 14: Examples of structure toppling over.  
Figure 15: Examples of the pancake-like damage.  
In RC structures, changes in column lengths within the floor or structure due to different reasons cause the formation of short columns, and plastic hinges form in these columns during an earthquake. Examples of structural damage occurring in short columns created from sloping ground and band-type windows are shown in Figure 17.  
Reinforced concrete structures built adjacent to each other may cause different damages to neighboring structures by causing a bounding effect during an earthquake. Different floor levels negatively affect the damage that may occur due to collision. Additional shear forces resulting from the bounding effect, which is not taken into account in the design, cause significant damage, especially to the columns that will be subjected to the impact of the collision. The damages that occur if the floor levels are not the same are shown in Figure 18.  
Figure 16: Buildings that have suffered partial or total collapse due to soft story formation.  
Figure 17: Examples of short column damage are (**a**) due to the hill slope effect and (**b**) due to the band-type window effect.  
Figure 18: Pounding damages occur in structures with different floor levels.  
The fact that the floor levels of adjacent buildings are the same prevented the damage from increasing. Examples of damage to neighboring structures with floors at the same level are shown in Figure 19.  
Column and beam connection regions are stressed the most in reinforced concrete structures under earthquake loads. When appropriate joint design and manufacturing are not carried out, plastic deformations occur at these joints in a severe earthquake. One of the typical damage examples seen in the region is the plastic hinge that occurs in the column end regions, as shown in Figure 20.  
Various levels of damage occurred in the structures due to the low-strength concrete, inadequate concrete cover, insufficient amount of transverse reinforcement and crossties, poor workmanship, and connections details. Examples of such damage are shown in Figure 21.  
The low strength of the infill wall materials used in reinforced concrete structures and poor workmanship have created X-shaped shear cracks in these walls. Examples of damage caused by shear force are shown in Figure 22.  
Many of the reinforced concrete buildings in the district have closed heavy overhangs that extend beyond the floor area. These heavy overhangs, as well as the damage to the gable walls of the roof, also caused damage in some places due to the application of strong beams and weak columns. Examples of heavy overhang, gable wall, and strong beam-weak column damage are shown in Figure 23.  
Figure 19: Examples of damage to adjacent structures with the same floor level.  
Figure 20: Plastic hinge occurring at the upper ends of the column.