Research On Application Of The External Prestressing Technique In Strengthening Of Continuous Rigid-Framed Bridge

As an important branch of post-tensioned prestressing system, external prestressing technique can be employed for building, rebuilding, rehabilitation and strengthening project. External prestressing technique which is a kind of active strengthening method, can improve the component's capacity of bending resistance and shear resistance.Strengthening techniques of external prestressing are studied systematically in this thesis. On the basis of analyzing domestic and abroad related literatures and design specification, the fundamental theory and design method of external prestressing strengthening system are taken as main subjects invesitgated. Combining engineering case study, the reason of damaged concrete continuous beam and the corresponding design method and process of strengthening with external prestressing are disscussed. The following aspects are included in the thesis:(1) The current state and the development trend of the external prestressing technique are expounded, and the necessary and urgency of bridges strengthening illuminated.(2) The theory of bridge strengthening with external prestressing is demonstrated in detail, the key problems of external prestressing structure such as the stress increment, dynamical problem and stress loss etc are studied.(3) The formation, preservation, antivibration of external prestressing system are introduced, and commonly bar arranging way of external prestressing are summarized.(4) Combining theory with engineering practice, the design and calculation of the continuous rigid-framed bridge strengthening by external prestressing bridge are studied. The research findings can offer a reference for similar engineering.