Paper number 1099

FIBER OPTIC SENSORS FOR STRAIN MONITORING IN CONCRETE BEAMS REPAIRED WITH COMPOSITE MATERIALS

Diaz-Carrillo, S.1, Salaverria, J.2, Casas, J.R2., Guemes, J.A.1

1Aerospace Materials Department, ETSI Aeronauticos, UPA
Pza. Cardenal Cisneros, 3. 2804OMadrid, Spain
2Construction Engineering Department, UPC
C. Gran Capitan s/n. Module Cl. 08034 Barcelona, Spain

Summary Advanced composites offer some advantages over traditional procedures for repairing concrete structures, due to their optimal corrosion properties, low weight and decreasing costs. Thin cured laminates may be externally bonded or dry fabrics can be wet applied and in situ cured over the concrete structure, conforming to itssurface irregularities.
Fibre optic strain sensors, specially Bragg gratings, show some advantages when compared to conventional strain gauges: absolute measurements, spectrally encoded output, no EMI, no drift (long-term stability), low size, multiplexing capability and their ability to be embedded into laminates without degradation.
The combination of both techniques is easy and offers important advantages. The long- term mechanical behaviour of the repair may be checked and information on environmental degradation could be obtained. On the short term, information on the stress transfer from the concrete to the laminate is obtained, and the validity of models is verified. Tests on a concrete beam repaired with CFRP and instrumented with Bragg gratings are reported. A finite element model was also developed.
Keywords repair, concrete, CFRP, fibre optic sensor, Bragg grating.

Theme : Reinforcement and repair in Civil Engineering and Building Construction

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