Distributed strain measurement of a large-scale reinforced concrete beam-column assembly under cyclic loading

In this paper, comparisons are made between the performances of two kinds of distributed sensors, Electric Time Domain Reflectometry (ETDR) cable sensor that is based on the propagation of electromagnetic waves in an electrical cable and Brillouin Optical Time Domain Reflectometry (BOTDR) optical sensor that is based on the propagation of optic pulses and Brillouin scattering that occurs when light is transmitted through the optic fiber. A cable sensor was mounted near the surface of the 80% scale beam-column reinforced concrete assembly that was loaded cyclically until the shear failure occurred. The embedded depth was 0.5 inches. At the same time, a fiber optic sensor was mounted on the surface of the assembly with two installation procedures called Point Fixation (PF) Method and Overall Bonding (OB) Method to measure the strain distribution. Both BOTDR and ETDR sensors were subjected to tension and compression in one loading cycle. Strain distributions obtained from the ETDR and BOTDR sensing systems under different cycle loadings were compared with each other. They were also compared with those measured from the traditional strain gauge.

[1]  Ayo O. Abatan,et al.  Crack damage detection of concrete structures using distributed electrical time domain reflectometry (ETDR) sensors , 1999, Smart Structures.

[2]  Kevin M. O'Connor,et al.  GeoMeasurements by Pulsing TDR Cables and Probes , 1999 .

[3]  Toshio Kurashima,et al.  Measurement of Strain Distribution in Structures Using Optical Fiber , 1997 .

[4]  Ayo O. Abatan,et al.  High-sensitivity electrical TDR distributed strain sensor , 2000, Smart Structures.

[5]  Zhishen Wu,et al.  Crack Measurement of Concrete Structures with Optical Fiber Sensing , 2000 .

[6]  Ch Benson,et al.  Time-domain Reflectometry (TDR) in Geotechnics: A Review , 1999 .

[7]  Zhishen Wu,et al.  An experimental investigation on continuous strain and crack monitoring with fiber optic sensors , 2002 .

[8]  Genda Chen,et al.  Damage Detection of Reinforced Concrete Beams with Novel Distributed Crack/Strain Sensors , 2004 .

[9]  T. Horiguchi,et al.  Tensile strain dependence of Brillouin frequency shift in silica optical fibers , 1989, IEEE Photonics Technology Letters.

[10]  David Pommerenke,et al.  Crack detection of a 15 meter long reinforced concrete girder with a single distributed cable sensor , 2003 .

[11]  Xiaoyi Bao,et al.  Strain measurement of the steel beam with the distributed Brillouin scattering sensor , 2001, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[12]  Genda Chen,et al.  Signal loss, spatial resolution, and sensitivity of long coaxial crack sensors , 2004, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[13]  Farhad Ansari,et al.  Embedded fiber optic crack sensor for reinforced concrete structures , 2000 .