## 1 Introduction  
In areas that are prone to frequent earthquakes, it is crucial to ensure that reinforced concrete buildings always maintain their stability and structural integrity. Achieving this requires extensive study of the various structural components and their response to seismic loads. Reinforced concrete structures are widely used due to their ability to carry these loads, but their seismic response is highly dependent on reinforcement detailing and arrangement. Stirrups, which form an integral part of the reinforced concrete structure, increase the load-carrying capacity of columns and beams to resist lateral forces during earthquakes. Stirrups prevent buckling by confining the concrete and improve the seismic performance of the structure by increasing energy dissipation. In order to obtain a comprehensive assessment of the seismic behavior of reinforced concrete structures, this study specifically focuses on the effect of two different types of stirrups, i.e., hooked and unhooked stirrups. Previous research has shown that hooked stirrups can improve energy dissipation and ductility by providing additional restraint to the concrete core, while unhooked stirrups, although widely used, may provide relatively limited benefits in this regard [1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18]. [PERSON] et al. [19] estimated the effect of corrosion on the capacity and ductility in their study. [PERSON] et al. [20] have compared numerical and analytical predictions for the shear capacity of fiber-reinforced concrete beams based on experimental literature tests considering the role of the fracture energy in the size effect. [PERSON] et al. [21] have investigated the effects of the hook angle and hook length of the sub-standard transverse reinforcement on the compression behavior of the columns in their experimental study. In her thesis study, [PERSON] [22] compared the compressive strengths, maximum load deflections, ductility, and stress-strain relations of confined concrete using experimental setups with hook angles of 135\({}^{\circ}\), 112.5\({}^{\circ}\), and 90\({}^{\circ}\). While analyzing the obtained data, she considered and compared mathematical concrete models proposed by [PERSON], [PERSON] and [PERSON], and [PERSON]. [PERSON] [23] found in his experimental thesis that when hook angles are 90/135\({}^{\circ}\), 90\({}^{\circ}\) hooks open and 135\({}^{\circ}\) hooks do not. As a result of this opening, the longitudinal reinforcement starts to buckle in this direction, since the buckling length perpendicular to the 90\({}^{\circ}\) stirrup arm direction increases. This study has shown that it is a very important requirement that the stirrup hook angles should be 135\({}^{\circ}\) as specified in the regulations; otherwise, if even one of the hooks is 90\({}^{\circ}\), unexpected capacity reductions and collapses are inevitable because of the asymmetrical confinement effect caused by stirrup opening and early longitudinal reinforcement buckling. Many researchers are working on developing new strategies to address stirrup deficiencies. The study by [PERSON] et al. [24] investigates the impact of the confined concrete constitutive law used on the flexural strength and curvature ductility of reinforced concrete sections strengthened by wrapping them with FRP (fiber-reinforced polymer). The stress-strain relationship of confined concrete is affected by the number of layers, the type of FRP used, as well as the size and shape of the section. [PERSON] et al. [25] have suggested an innovative hybrid reinforcement method that incorporates both traditional longitudinal steel reinforcement and FRP stirrups. Fiber-reinforced polymers (FRP), such as carbon fibers (CFRP), glass fibers (GFR), and aramid fibers (AFRP), have superior properties compared with steel stirrups to enhance the strength and ductility capacities of concrete columns [26; 27]. [PERSON] et al.