Several research projects carry out experiments on a newly built 45 m long research bridge, called openLAB.
This contribution showcases the synergetic collaboration of the two research projects IDA-KI and smart_tendon in a joint experimental investigation on one 15 m long precast and prestressed girder.
The girder was equipped with distributed fiber optic sensors (DFOS) prior to casting, as DFOS provide detailed insights into the structure’s inner with unprecedented spatial resolution.
The suitability of different installation methods for structural health monitoring applications from the beginning of the structures' existence was studied.
DFOS were either embedded in the concrete matrix, glued to the longitudinal reinforcement, included in prestressing strands in direct bond or inside strands of a post tensioned tendon.
A 15 m long girder was tested in a 4-point bending test prior to its installation into the bridge.
Robust DFOS with a monolithic cross-section, integrated directly into the concrete matrix, enable reliable crack monitoring and anomaly detection.
Newly formed cracks can be identified with periodic measurements, even after the cross-section is fully compressed again.
This provides information on the load history.
DFOS integrated into tendons allows for efficient construction progress without the need for additional trades.
Strain curves in the linear elastic state can be accurately mapped.
A transition to the cracked state is indicated by a disproportionate strain increase.