Strain measurement in a concrete beam by use of the Brillouin-scattering-based distributed fiber sensor with single-mode fibers embedded in glass fiber reinforced polymer rods and bonded to steel reinforcing bars

The strain measurement of a 1.65-m reinforced concrete beam by use of a distributed fiber strain sensor with a 50-cm spatial resolution and 5-cm readout resolution is reported. The strain-measurement accuracy is [+ or -] 15 [micro][epsilon] ([micro]m/m) according to the system calibration in the laboratory environment with non-uniform-distributed strain and [+ or -] 5 [micro][epsilon] with uniform strain distribution. The strain distribution has been measured for one-point and two-point loading patterns for optical fibers embedded in pultruded glass fiber reinforced polymer (GFRP) rods and those bonded to steel reinforcing bars. In the one-point loading case, the strain deviations are [+ or -] 7 and [+ or -] 15 [micro][epsilon] for fibers embedded in the GFRP rods and fibers bonded to steel reinforcing bars, respectively, whereas the strain deviation is [+ or -] 20 [micro][epsilon] for the two-point loading case. OCIS codes: 290.5830, 060.2370.