Applied Research On The Thin-walled Box Girder Of CFRP External Prestressed Self-compacting Concrete

Concrete thin-walled box girders have been widely used in the modern concrete bridge, for its good overall mechanical properties of space. With the increase of bridge span, traditional prestressed concrete thin-walled box girder faced with difficult problems in structure's high self-weight, casting, steel corrosion and so on. In order to solve these problems, two new materials, self-compacting concrete and CFRP, have been introduced in the thin-walled box girder of CFRP external prestressed self-compacting concrete. Thus, thin-walled box girder of CFRP external prestressed self-compacting concrete colligated the particular characteristics both self-compacting concrete vibration-free, environmental protection, energy saving and CFRP high strength, light weight, non-corrosion and so on. A series of experimental and analytical research of these two new materials in the application of thin-walled box girder have been investigated as follows, and the desired results were obtained.1. Considering particular characteristics of the concrete thin-walled box girder , with the use of external prestressing technology, thin-walled box girder of CFRP external prestressed self-compacting concrete was designed through the introduction of self-compacting concrete and CFRP. In particular, a detailed design on thin-walled box girder of the anchor side and steering block was carried out.2. In order to solve the problem of concrete pouring, which is caused by thin-walled and steel-intensive layout, the preparation of C60 high-strength self-compacting concrete were made through a large number of adaptive test. Moreover, the basic mechanical properties of self-compacting concrete were analyzed.3. To bring into full play to the characteristics of high-strength carbon fiber sheet, the implementation of the external prestressing was made. At the same time, in order to overcome the defect of their relatively low shear strength, the method on CFRP prestressed imposed in vitro was taken on, which is suitable for the combined fiber sheet dedicated anchor. A patent certificate was issued by the People's Republic of China State Intellectual Property Office.4. With the application of carbon fiber sheet and the preparation of C60 high-strength self-compacting concrete , the implementation of External Prestressing Technology was made in thin-walled box girder of CFRP external prestressed self-compacting concrete . This paper analyzed the plane section assumption, the incremental external prestressing, load - deflection curves, and shear lag effect in the elastic phase of external prestressed self-compacting concrete thin-walled box girder through the concrete simply-supported thin-walled box static load test.