Durabiltiy Analysis For Prestressed Concrete Continuous Rigid Bridge

Corrosion of prestressing tendon is one of the main durable issues of the prestressed concrete structures, which always is the primary factor affecting the performaces of prestressed concrete structures. Analysing the durability of prestressed concrete continuous rigid bridges can scientifically assess the durability of the bridge in service and predict the remaining life, which can help make correct treatments. In addition, it also provides references to durability analysis of newly-built bridges, which is in favor of improving the design level and construction quality, ensuring the safty in the whole life cycle. In combination with actual engineering project, this thesis deeply analyses the durability of the prestressed concrete continuous rigid bridge. The main findings are presented as follows:1. Chloride diffusion is taken as the primary factor to the corrosion of prestressing tendon. The corrosion initiation time is related to chloride diffusion coefficient, the equilibrium chloride concentration at the concrete surface, the critical chloride concentration at which corrosion begins and the concrete cover, and each of them has a lognormal distribution. Monte Carlo simulation method is employed to present the corrosion initiation time under different levels of corrosion.2. Existing methods in calculating the corrosion rate are summed up. According to different chloride diffusion environment, high, medium and low deterioration are defined, and then the chloride corrosion rates are calculated. Based on the above, time-variant area of prestressing tendon subjected to different corrosion deterioration for the prestressed concrete continuous rigid bridge can be predicted.3. After corrosion, the effect to ultimate bearing capacity of the structure is considered. Compared with the load effect, the failure time can be deduced.4. The service performance of the structure is considered, and then the initial cracking time is estimated. The stiffness of the structure deteriorates after corrosion, and the deflection at the midspan under moving load are calculated.