## 3 Shake Table Study
### Material Properties  
The concrete chosen for the experimental framework was specifically manufactured to have a low compressive strength of about 9 MPa. This choice aimed to replicate the poor quality often found in older RC structures, particularly those built before strict seismic design codes were enforced. By using weaker concrete, the research sought to reflect the seismic vulnerabilities common in existing RC buildings, providing valuable insights for retrofitting strategies. The study's concrete showcased these intentionally reduced strength characteristics, accurately reflecting the construction quality issues seen in older infrastructures. In order to thoroughly evaluate the intricate stress-strain relationships inherent to the steel material, a comprehensive series of tests was conducted on three distinct samples, which were further complemented by the inclusion of transverse reinforcement that possessed the same diameter specifications, and through this meticulous examination, a 473 MPa yield stress value was determined, alongside a 643 MPa ultimate tensile stress value that was also established. The results of the tensile tests conducted indicated with a significant level of confidence that the steel in question successfully met the stringent strength criteria as set forth in the established guidelines of ASTMA615/A615M-05 [33], thereby affirming its suitability for structural applications. To analyze the material properties of the load-bearing tube made from HS542 \(\times\) 1.5, two dog bone-shaped samples were extracted for evaluation. Uniaxial tensile tests were  
Figure 6: Instrumentation of Specim 2.  
performed at the Turkish Standards Institution's (TSI) Material Testing Laboratory, emphasizing precision and accuracy. The yield stresses were evaluated using the 0.2% proof stress criterion, showing values of 397 MPa and 431 MPa, indicating a notable difference in properties. The maximum engineering stresses ranged from 494 MPa to 520 MPa, with an ultimate strain at fracture of around 0.30 or more, reflecting significant ductility. The average yield stress was approximately 414 MPa, while the ultimate tensile stress was about 507 MPa, providing a comprehensive understanding of the material's mechanical properties. In the development of a reliable 1:3 scaled model designed to analyze the seismic behavior of outdated and deficient RC frames, meticulous attention was devoted to the selection of materials and the scaling of dimensions. Specifically, concrete with a relatively low compressive strength and a minimized maximum aggregate size was selected to maintain geometric similarity in the ratio of aggregate to member size while simultaneously preventing unrealistic manifestations of strength increase. The adjustment of steel reinforcement bars in terms of both diameter and spacing was undertaken to guarantee that the total steel ratio accurately represents real-world full-scale conditions. Adhering to recognized principles of similitude, a scale factor of one was designated for the modulus of elasticity for both concrete and steel, as presented in Table 1. This methodology confirms that the stress-to-strain relationships closely correspond to those of the prototype, thus maintaining the precise stiffness attributes and deformation behaviors of the model. Geometric scaling was conducted, adhering to a strict 1:3 ratio for all relevant linear dimensions, encompassing member length, cross-sectional height, and cover to reinforcement. By systematically diminishing these dimensions, the model retains consistent shear span-to-depth ratios and member slenderness values, resulting in a nearly identical distribution of bending moments, shear forces, and anchorage requirements under scaled seismic loading.