POST-EVALUATION OF THE FIRED CONCRETE BRIDGES REPAIRED BY STEEL PLATE AND CONCRETE COMPOSITE STRENGTHENING TECHNIQUE

摘要

TheYao Zhou Uplink Viaduct damaged in a fire accident was repaired using steel plate and concrete composite strengthening (SPCCS) technique. After strengthening and servicing normally for 1.5 years, two loading tests, meanwhile, a three-day traffic information observation and dynamic strain monitoring were carried out. The static loading test and monitoring results all showed that the Yao Zhou Uplink Viaduct had good service condition since reinforcement, which satisfying the safety requirement. In order to evaluate the effectiveness of the SPCCS technique indepth, structural behaviour under the ultimate limit state (ULS) and the serviceability limit state (SLS) were analyzed. The SLS and ULC of the key sections before and after reinforcement were calculated using the simplified formula and the finite element models calibrated by filed test results. The post-evaluation results showed that the behaviour of the spans damaged in fire accident could be improved obviously under the SLS using SPCCS technique, as well as the bridge stiffness enlarged than the original bridge structure. What's more, the ultimate bearing capacity (UBC) of the key sections was improved about 75% using SPCCS technique, which was two times as the most disadvantageous load effect combinations.