## 1 Introduction
[18] proposed the theoretical formulas for internal force and bending moment of ECC-layered reinforced RC beams and analyzed the influence of the influential parameters, such as ECC substitution rate and reinforcement rate, on the yield moment, ultimate moment, and ductility of the beams. [PERSON] et al. [19] investigated the flexural synergistic effect of ECC-reinforced RC beams and analyzed the damage mode, crack development mode, and crack width of the specimens. An effective model was proposed to predict the crack extension mode of ECC-RC. ECC is also often used in combination with RC and FRP for better performance. [PERSON] et al. [20] used high-strength ECC for the reinforcement of RC members and found that 20 mm thickness of ECC increased the bearing capacity by 8.3%, and the use of FRP further enhanced the bearing capacity and slowed down the early crack development. The failure model of FRP changed from debonding to fracture after the introduction of ECC [21]. By taking advantage of the large tensile strain of ECC, the cracks can be effectively controlled, avoiding the debonding of FRP after cracking of RC. [PERSON] et al. [22] conducted an experimental study on the bending behavior of ECC-CFRP beams, and when the ECC thickness is small, the CFRP failure mode is still debonding. The contact relationship between ECC and tensile reinforcement can significantly affect the bending performance of RC beams, rather than the ECC thickness. The proposed load capacity prediction model can better predict the load capacity of two after reinforcement. [PERSON] et al. [23] placed the ECC layer on top of over-reinforced beams and investigated the effect on their bearing capacity and ductility. The test results show that the ECC layer can effectively improve the brittle fracture characteristics of over-reinforced beams, and the ductility is improved. Currently, a large number of research works have focused on the effect of ECC on the bearing performance of members. In addition, the study of ECC in beam-column joints has also attracted the attention of scholars [24; 25; 26]. [PERSON] and [PERSON] [26] used ECC to improve the seismic behaviors of the beam-column joints. The test results showed that the use of ECC materials in the beam-column joint region significantly improved the shear strength and cracking response of the joints. The specimens with ECC materials all showed little spalling, while the conventional concrete specimens showed extensive spalling of the concrete. [PERSON] and [PERSON] [27] investigated the performance of ECC in the joint region by cyclic loading tests on full-size beam-column specimens. The crack spacing and crack width of the ECC were significantly smaller than those of the RC specimens, and the ECC had a higher ultimate bearing capacity and ductility, which were higher than those of the RC specimens. [PERSON] and [PERSON] [28] used fiber-reinforced polymer rebars, such as carbon fibers and glass fiber-reinforced plastics, which can be an effective, sustainable, and durable solution to improve the durability of reinforced concrete structures in corrosive environments. In general, crack widths can be reduced by reducing the stresses on the reinforcement, which can be achieved by increasing the longitudinal force reinforcement on the top surface of the beam end. However, the use of dense reinforcement not only results in increased steel consumption but also presents challenges in concrete vibration, potentially leading to difficulties in ensuring construction quality. Furthermore, augmenting the negative reinforcement at the extremity of the frame beam will have a deleterious effect on the seismic structure of strong columns and weak beams. Therefore, it is of practical significance to seek a method to control the maximum crack width at the end of concrete frame beams by making full use of the superior anti-cracking performance of ECC materials [29; 30].