## 4 Analysis of Heavily and Moderately Damaged Structure Materials in the Elbistan Region
### Non-Destructive Experimental Tests  
In order to conduct a thorough structural analysis of buildings and implement effective strengthening measures in them, it is necessary to obtain reliable information about their  
Figure 8: Concrete sampling, red circles: Aggregate size and segregation are shown in the figure.  
Figure 7: Comparison of concrete strength values according to various regulations.  
in situ compressive strength. This is particularly important when assessing the seismic capacity of existing buildings, which have often been designed to withstand only gravity loads or were constructed according to outdated seismic codes with low safety factors [50]. Typically, this information is obtained by conducting compression tests on cores extracted from structural elements of the buildings under analysis [51; 52].  
The use of destructive coring testing is generally more accurate than non-destructive testing [53; 54]. However, coring testing is expensive, invasive, time-consuming, and, in some cases, impossible to perform. To minimize the need for coring, non-destructive testing can be used in conjunction with coring testing to assess the strength of a structure, gather more information, and obtain a higher level of knowledge about the variability in the strength of the structure at a lower cost [55; 56; 57]. Schmidt (SH) and Ultrasonic Pulse Velocity (UPV) tests are commonly used together in practice to provide a comprehensive evaluation of concrete strength [58]. This paper aimed to introduce a new approach to predicting the concrete compressive strength of a given structure. This approach uses ultrasonic testing to non-destructively determine the dynamic and static moduli of the elasticity of concrete [59]. [PERSON] et al. (2023) also utilized a new multi-objective optimization method to evaluate the compressive strength and variability of concrete by combining several non-destructive techniques [60].  
In this study, only core samples were taken from the structures, and in situ non-destructive experiments were conducted. The UPV and Schmidt tests were carried out both in situ and in the laboratory environment on samples taken from the buildings (Figure 9).  
For the buildings produced post-2000, their UPV results were close to values that are considered good. Although the strength of their concrete was low, the age of the concrete and the use of ready-mixed concrete increased its quality. The lowest value obtained for these buildings was 3.57, while the highest was 4.9. Further, the UPV values of the moderately damaged structures were all close to one another. For the pre-2000 buildings, their concrete was of a low quality and porous, and its granulometry was not produced correctly. Although the pre-2000 buildings generally recorded a bad UPV value of 2, some structures recorded values close to or above 3, which were close to the average value. However, the Schmidt hammer strength values of the samples differed among the pre- and post-2000 buildings, as well as the UPV values. The granulometry of the aggregates used, segregation, and water-cement ratio all affects the strength of concrete. This study found that the concrete of the pre-2000 buildings performed poorly with regard to these factors. Values of around 14 were obtained for these pre-2000 buildings, while those for the post-2000 buildings varied between 25 and 40. Some of the values of the post-2000  
Figure 9: Non-destructive tests.  
buildings showed that their concrete was of a higher quality than that of the other buildings. In Figure 10, the UPV and Schmidt test values are compared to each other.