# Plastic Properties of Prestressed High-Strength Steel Reinforced Concrete Continuous Beams
## 1 Introduction  
In recent years, the requirements of architectural design have been continuously improved. High-strength steel with strength grades of Q460 and Q690 is widely used in large-span and high-rise building structures, such as the Bird's Nest, the Sony Center, and the Yokohama Landmark Tower [1], due to its high yield strength, good plasticity, and weldability [2; 3; 4]. To meet the needs of architectural design, high-performance composite structures have gradually attracted the attention of the engineering community [5]. One of the ways to form high-performance composite structures is to use high-strength and high-performance building materials instead of traditional building materials [6; 7]. The application of high-strength steel to steel reinforced concrete (SRC) structures can greatly improve the mechanical performance of SRC structures [8; 9; 10]; however, with the increase in building span or load, the application of SRC structures in construction engineering is limited, because the crack width and component deflection cannot meet the requirements of normal use [11]. The prestressed steel reinforced concrete (PSRC) structure can compensatefor this shortcoming [12]. Applying prestress in SRC structures can improve the crack closure of SRC structures [13], reduce the deflection of the structure [14], and improve the utilization efficiency of component materials [15]; therefore, PSRC structures have broader application prospects. To meet the needs of the development of building structures, further reduce the section size of components, and make full use of building space, it is necessary to apply high-strength steel to PSRC structures to improve structural performance. Because most of the structural forms of buildings use statically indeterminate structures, compared with normal beams, continuous beams are more widely used in practical engineering and are suitable for plastic design methods considering internal force redistribution, which can give full play to the performance of materials and further save materials. Studying the plastic performance of prestressed high-strength steel reinforced concrete (PHSSRC) beam is helpful for the popularization and application of high-strength steel in prestressed steel reinforced concrete composite structures. In recent years, many scholars have studied the PSRC structure. [PERSON] [16] carried out a fatigue test of prestressed steel reinforced concrete composite beams, and the results showed that applying prestress to the structure can improve the fatigue resistance of steel reinforced concrete composite beams. Since most of the actual projects are statically indeterminate structures, [PERSON] [17] carried out research on the plastic performance of prestressed steel reinforced concrete continuous composite beams and proposed the calculation formula of the length of the equivalent plastic hinge zone and the bending moment adjustment formula. [PERSON] [18] studied the plastic properties of prestressed concrete continuous composite beams with encased H-shaped steel and found that the length of the equivalent plastic hinge zone of the specimen was less than 0.64 times the effective height of the beam section. When the relative plastic rotation angle was less than 0.817 \(\times\) 10\({}^{-5}\), the moment modulation coefficient increased with increasing plastic rotation angle and was not more than 0.44, and the moment modulation amplitude of the PSRC structure was given. Scholars [19; 20; 21; 22] have also studied the plastic properties of PSRC beams and proposed the amplitude of bending moment modulation. In addition, some scholars [23; 24; 25; 26; 27; 28; 29] analyzed the failure mode, crack development, and stiffness change of PSRC members and explored the deformation capacity of PSRC beams based on the stiffness change of the section.