Research on twice prestress technology

Twice prestress technology which divides the casting concrete and prestressing strands of prestressed concrete structures into two stages is a novel technology. With reference to the relative research references, this paper firstly introduced the research progress on the load and deformation characters of simply-supported beam and continuous beam in which twice prestress technology has been applied. It concluded that twice prestress technology has obvious advantages in controlling the deformation of PC structures and also improves the efficiency of prestressing strand; However, the design method of twice-prestressed concrete beam, the mechanical character of joint surface, the fatigue and dynamic characters of this novel structure and application of high performance material in this structure are the focus of research for this technology and future development trend.