Study On Creep Deformation And Construction Technique Of Tianjin-Binhai Light Railway Bridge

In the Tianjin-Binhai light railway , 87% of the track are bridge, the super structure of the bridge beam is mainly composed of the pre-stressing reinforced concrete structure. It is very important to make the analysis of the creep on the pre-stressing reinforced concrete.Firstly, this paper introduces the basic concept of creep deformation in prestressed concrete and analyses the current situation of China and abroad for it. The intrinsic factors and the external factors of it are discussed too. And then, the principle of space distribution and name is confirmed for the monitoring point according to the character of the project. There are many items, such as concrete hydration heat, the study on relationship between strength and elastic modulus of concrete and changes of time, the testing result of friction resistance generated by prestressing , the testing result of mid-span cross-section stresses, the study on the creep deformation of prestressed concrete beam , and so on.With the measurement on the bridge for long time and the simulation calculated by using the ANSYS to make the secondary development, a conclusion is reached : the arching factor in the Tianjin-Binhai light railway is relatively small; that two months after the stretching, the creep develops very fast, about 70% of the total creep completes during this period.For the quality of the concrete (mixture ratio, material quality , strength, and elasticity ) are ensured to reach the design standards, three months after the stretching of the pre-stressing strain it can start casting of the concrete to construct the bearing of the platform. If this work needs to be started fifty days after the stretching, the elasticity modulus of the concrete should be tested to be not less than 41.4Gpa. If the time is less than fifty days , this construction shall not be started.