Structural health monitoring of an existing PC box girder bridge with distributed HCFRP sensors in a destructive test

摘要

The application of hybrid carbon fiber reinforced polymer (HCFRP) sensors was addressed to monitor the structural health of an existing prestressed concrete ( PC) box girder bridge in a destructive test. The novel HCFRP sensors were fabricated with three types of carbon tows in order to realize distributed and broad-based sensing. HCFRP sensors are characterized by long-gauge length and low cost. The HCFRP sensors were bonded to the bottom and side surfaces of the existing bridge to monitor its structural health. The gauge lengths of the sensors bonded to the bottom and side surfaces were 1.5 m and 1.0 m, respectively. The HCFRP sensors were distributed on the bridge for two purposes. One was to detect damage and monitor the structural health of the bridge, such as the initiation and propagation of new cracks, strain distribution and yielding of steel reinforcements. The other purpose was to monitor the propagation of existing cracks. The good relationship between the change in electrical resistance and load indicates that the HCFRP sensors can provide actual infrastructures with a distributed damage detection and structural health monitoring system.