ABSTRACT
The problem of mid-spans deflection of long-span prestressed concrete continuous beam bridges have been concerned by bridge workers all over the world. Creep of concrete and prestress loss are the main factors that affect the deflection of midspan. In order to study the influence of the two on the midspan deflection, Midas Civil 2019 is used to establish a finite element model based on the actual project of Nenjiang Bridge, and the overall stress state and displacement of Nenjiang Bridge in the use stage are analyzed. Based on JTG D62-2004 (China code), CEB-FIP (1990) model, creep model adopted in European concrete code and ACI model, the deflection value of midspan caused by concrete creep in 12 years after the completion of bridge is analyzed. Using the method of comparative argumentation, the time rule of creep to midspan deflection is discussed. Based on the prestress loss, the influence of different prestress loss levels on the long-term deflection of the midspan is studied, and the sensitivity of the roof bundle and the floor bundle to the deflection at different midspan positions is analyzed. Based on the theory of “zero moment”, this paper analyzes the causes of midspan deflection of the bridge from the angle of stress, and puts forward effective measures to control the midspan deflection of the prestressed concrete continuous beam bridge. These studies have certain guiding significance in the practical engineering, especially in the measures of controlling the midspan deflection of the multispan long-span prestressed concrete continuous beam bridge.
