EXPERIMENTAL STUDY OF ULTIMATE BEHAVIOR OF EXISTING BRIDGE USING DESTRUCTIVE TESTING

The actual loading-carrying capacity and the behavior during an ultra state have always been concerned by researchers. However, there is little progress in this orientation due to the difficulty in actual bridge destructive tests. This paper carried out a destructive test of a forty-three-year-old reinforced concrete simply-supported T-beam bridge in Ningxiang County, Hunan province, to investigate the mechanical performance of the bridge during the whole process to destruction and structural reaction in a limit state. Based on the detailed pre-investigation of the material strength, the structure damage and degradation before the experiment, two 5000 kN jacks were employed to load the bridge to failure, and the finite element analysis was carried out to be compared with the experiment results. The test results showed that the tested bridge exhibit non-linear behavior in some stages which does not occur in structure models and finite elements analyses, affected by the factors due to the traverse connection, boundary conditions and initial damage; but the results of the finite element analysis still matched that of the experiment in some degree if the materials degradation was taken into consideration. A typical failure mode for bending structure was observed, which was caused by yielding of reinforcing bar and crushing of concrete; however, besides the crushing of upper concrete, the bridge bearing was also damaged, which indicates that the destruction form of the tested bridge maybe controlled by multiple factors.