## 1 Introduction  
Precast and prestressed reinforced concrete is favored for several advantages it has over cast-in-place reinforced concrete, primarily for its time and energy efficient construction as well as it capability to withstand much higher loads concerning serviceability requirements and to minimize on-site error. The connection between the individual precast concrete elements is the crucial part in designing safe, durable, and efficient structures. One of these connections, which is, used for multi-story buildings and bridges is the dapped end, which is formed by notching the bottom corner of the beam and moving the supporting location to a higher point in the cross-section [1], as shown in Figure 1. This brings several significant benefits to the structure. By supporting the dapped end of the beam on a corbel, on inverted T-beams, or on L-shaped edges, the overall structural height and dead weight of the building can be greatly reduced [2, 3], thereby making the construction more sustainable and efficient by requiring significantly less material and labor input. Additionally, by raising the bearing point on the element and lowering its own structural height at the supporting end, the lateral stability of the isolated element is greatly increased [4]. Even though the advantages of the dapped end beam have promoted its extensive practical usage in structural design, too few studies have been made on its behavior when the reinforcement used in the beam is prestressed. The abrupt change in geometry at the notched end causes a complex strain distribution at the area around the re-entrant corner [1; 3]. The part of the element which has these geometrical discontinuities is called a disturbed region. Such regions are more likely to fail first compared to other parts of the element and are prone to fail due to shear forces rather than flexure [5]. [PERSON] et al. (2015) [2] conducted a review of 111 dapped-end beam studies and concluded that 93.69% of the beams experienced failure as a result of shear forces. The important factor to consider here is that shear failure can occur immediately, and rarely do these types of failures have early warning signs [2], but because of the complexity of the flow of stresses, accurately predicting the failure load using conventional design methods is nearly impossible [1]. That is why dapped-end beams are designed using one of the two general approaches: the shear-friction method defined by the PCI (Precast/Prestressed Concrete Institute) [6], or the different strut-and-tie models (STM) [7; 8; 9; 10; 11] adopted by many international design codes such as ACI-318 (American Concrete Institute) [12], fib Model Code [8], and Eurocode 2 [7]. Each model weights certain calculation parameters differently, and thus, the results of each model differ, but adding prestressed reinforcement to the dapped end increases the complexity of the flow of stresses even more, and the results diverge even further [5]. Studies have repeatedly analyzed the behavior of non-prestressed dapped-end beams, but few studies have analyzed how varying intensities of prestressing and different arrangements of prestressed reinforcement, draped or straight, affect the shear strength of such a beam. It was ascertained that when the prestressing force compresses the element, the shear strength increases as the force intensifies [13; 14; 15; 16; 17; 18]. In a dapped-end beam, the existence of such a force occurs when the tendons are extended to the nib, resulting in the compression of the element by force P\({}_{1}\), as depicted in Figure 2. Due to technical reasons and practical difficulties in manufacturing, such reinforcement arrangements are not feasible in many elements, particularly in thin-stemmed members [16]. The problem arises when the prestressed reinforcement is arranged in such a way that the force P\({}_{2}\) induces tension at the re-entrant corner A, and the shear strength is thereby reduced [14; 15].