Construction Control Of Long-span Prestressed Concrete Truss Beam Bridge

Because of its big stiffness,good durability, light weight, saving steel and cement, beautiful appearance etc,combined with the characteristics of clear structure and simple structure, small expansion joints,truss girder bridge has been more popularization and used in the bridge construction at present in recent years.However, during the actual construction process,because the bridge structure is influenced by various complicated factors,it makes cross section in different stages of the internal force and deflection of the design requirements.To make the bridge which is in the process of construction keep security and stability,the construction monitoring and control is always necessary.Through the analysis and summary of the development of the prestressed concrete truss beam and the developmental tendency of the construction monitoring techniques in our nation and abroad,drag of large-span prestressed concrete truss beam bridge engineering monitoring technology is studied in this paper.Relying on the south-to-north water transfer project4blocks Wu Jian production bridge as the research background,and basing on the construction process and characteristics of truss girder bridge,we propose scientific and reasonable construction control scheme,and finally develope a comprehensive monitoring system.In a word,we can try to provide reasonable reference for the same type bridge design, construction and monitoring in the future.The main research contents and achievements are as follows:(1) According to the specific project, we make the reasonable measurement and control scheme,then implement the stress and displacement of the truss girder bridge for the whole monitoring and control.Finally,we obtain the important original datums;(2) Based on the different construction phase,we establish the finite element analysis model for proceeding the numerical simulation,and compare them with the measured datums;(3) Considering the influence of the secondary stress(prestressed tendon relaxation,temperature variation,concrete shrinkage and creep),we simulate all kinds of the stress and deflection under different action of various factors.From the result of simulating, it can provide reference for bridge design and construction control calculation.