Existing Bridge Seismic Assessment And Carbon Fiber Reinforcement Technology

The concept of anti-seismic design based on structure's ductility has been worldwide accepted and paid much attention to since the San Femado seism in the United States in 1971.A ductility theory is adopted in anti-seismic design specification of New Zealand, Japan, the United States and the Europe country .Our country uses the 89 specification, which adopts a synthetic affection coefficient that covers up the inner require of ductility in bridge's structure. Factually there is no assurance for ductility in this coefficient. Furthermore, the seismic force is comparatively lower in design than in fact. Both of them necessarily increase the seismic risk. Therefore, all the ready-made bridges must be urgently analyzed to assess their anti-seismic capacity. The bridges that can't meet the requirements of ductility must be strengthened. This text goes into theories and methods of the assessment of bridge's anti-seismic ductility and presents a method of strengthening, which uses the carbon fiber. The main work is as follows:1.An inquiry of basic theories on anti-seismic ductility in bridge design. As to the ductility, I establish the relationship of structure member's curvature ductility to potential ductility and structure ductility and that of bridge's ductility to anti-flexure and anti-shear capacity to provide the theory reference for anti-seismic assessment.2.Presenting the concept of the coefficient that indicates the modification response of bridge's structure to seism. Adopting this concept, I certain the nature of factors and the amount of them, which influence the coefficient and set up the coefficient of modification response as one simplified means of bridge assessment.3.A studying of basic elements and operation steps in pushover analysis method, through which I set up the pushover analysis as another simplified means of the bridge assessment.4.According to the concept of confining concrete, I study the nature of CFRP confining concrete. By calculating I confirm that the CFRP confining concrete has an excellent anti- seismic quality.5.According to the foresaid means of assessment, applying the principle of three-rated precaution and twice designs, I develop the procedure of anti-seism, which strengthens the reinforced concrete bridge with carbon fiber.6.By an example, I verify that the foresaid assessment and strengthening is an easy practical method and has a value of the engineering application.