Investigation on packages of fiber Bragg grating for use as embeddable strain sensor in concrete structure

The paper covers detailed investigation on encapsulation and packaging of fiber Bragg grating (FBG) for strain sensing of concrete structures in embeddable form. Non-uniform strain distribution due to imperfect curing of the epoxy and its effect on the FBG spectrum has been studied experimentally and correlated with theoretical simulation. For a specific package, an optimal curing condition has been found and shown to have good repeatability. The successfully packaged sensor has been embedded in a concrete structure and the response has been found to be linear. Response of the sensor under static loading condition is compared with surface mountable electrical resistance strain gauge (ERSG) and embeddable type EFPI (extrinsic Fabry Perot interferometer) fiber optic sensor. The sensor has also been tested under dynamic loading of the structure.

[1]  K. Peters,et al.  Embedded optical fiber Bragg grating sensor in a nonuniform strain field: Measurements and simulations , 2001 .

[2]  J. Leng,et al.  Structural NDE of concrete structures using protected EFPI and FBG sensors , 2006 .

[3]  Roberto Montanini,et al.  Simultaneous measurement of temperature and strain in glass fiber/epoxy composites by embedded fiber optic sensors: I. Cure monitoring , 2007 .

[4]  Hiroshi Tsuda,et al.  Single-mode fibre optic Bragg grating sensing on the base of birefringence in surface-mounting and embedding applications , 2007 .

[5]  Tzu-Kang Lin,et al.  Online health monitoring and safety evaluation of the relocation of a research reactor using fiber Bragg grating sensors , 2006 .

[7]  D. Barker,et al.  Strain evaluation of epoxy-cured fiber-optic connectors , 2003 .

[8]  Nam-Sik Kim,et al.  Deflection estimation of a full scale prestressed concrete girder using long-gauge fiber optic sensors , 2008 .

[9]  Zhou Wan,et al.  Monitoring second lining of tunnel with mounted fiber Bragg grating strain sensors , 2008 .

[10]  Y.M. Chang,et al.  An investigation of bonding-layer characteristics of substrate-bonded fiber Bragg grating , 2005, Journal of Lightwave Technology.

[11]  Wei Zhang,et al.  Health Monitoring of Rehabilitated Concrete Bridges Using Distributed Optical Fiber Sensing , 2006, Comput. Aided Civ. Infrastructure Eng..

[12]  James M. W. Brownjohn,et al.  Development of fiber Bragg grating sensors for monitoring civil infrastructure , 2005 .

[13]  József Karger-Kocsis,et al.  Influence of Cure Regime on the Strain Development in an Epoxy Resin as Monitored by a Fiber Bragg Grating Sensor , 2007 .

[14]  Gerard Franklyn Fernando,et al.  Structural Integrity Monitoring of Concrete Structures via Optical Fiber Sensors: Sensor Protection Systems , 2003 .

[15]  Kuo Chun Chang,et al.  Online monitoring of highway bridge construction using fiber Bragg grating sensors , 2005 .

[16]  Hyoung-Jun Park,et al.  Accuracy improvement in peak positioning of spectrally distorted fiber Bragg grating sensors by Gaussian curve fitting. , 2007, Applied optics.