In the last two decades, a significant number of innovative sensing systems based on optical fiber sensors have been exploited in the engineering community due to their inherent distinctive advantages such as small size, light weight, immunity to electromagnetic interference (EMI) and corrosion, and embedding capability. A lot of optical fiber sensor-based monitoring systems have been developed for continuous measurement and real-time assessment of diversified engineering structures such as bridges, buildings, tunnels, pipelines, wind turbines, railway infrastructure, and geotechnical structures. The purpose of this review article is devoted to presenting a summary of the basic principles of various optical fiber sensors, innovation in sensing and computational methodologies, development of novel optical fiber sensors, and the practical application status of the optical fiber sensing technology in structural health monitoring (SHM) of civil infrastructure.

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Structural health monitoring of civil infrastructure using optical fiber sensing technology: a comprehensive review.

Smart concretes and structures are intelligent systems that have properties different from normal concrete, such as self-sensing and self-healing properties, or have the ability to react upon an ex

Smart concretes and structures: A review:

A coaxial cable sensor device with periodic impedance discontinuities along the length of its cable. The cable comprises an inner conductor, insulating material disposed around the length of the inner conductor, and an outer conductor disposed around the insulating material. The periodic impedance discontinuities are created by physical deformations or material alterations to at least one of the inner conductor, the outer conductor, and the insulating material. The sensor device may be used to measure temperature, pressure, strain, and acoustic waves in building structures, and is well suited for down-hole or underwater applications.

Coaxial cable bragg grating sensor

This study forms part of a literature survey on residual stresses in continuous fibre reinforced thermoplastic composites. After identification of the factors responsible for the thermal residual stress build-up in Part I [Parlevliet PP, Bersee HEN, Beukers A. Residual stresses in thermoplastic composites – A study of the literature – Part I: Formation of residual stresses. Composites Part A – Appl Sci Manuf, in press, doi:10.1016/j.compositesa.2005.12.025 ], experimental techniques to determine the magnitude and distribution of these stresses on various mechanical levels are outlined. The techniques are placed in the following categories: techniques utilising the intrinsic composite constituents’ material properties; techniques employing embedded “foreign” stress sensors; techniques based on in-plane and out-of-plane deformations, and destructive techniques.

Residual stresses in thermoplastic composites—A study of the literature—Part II: Experimental techniques

Cable tension force estimate using novel noncontact vision-based sensor

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.

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

Experimental studies on fiber optic sensors embedded in concrete

Studies on Damage Detection Using Frequency Change Correlation Approach for Health Assessment

Non destructive evaluation of residual stresses in welded plates using the barkhausen noise technique

The application of experimental techniques for the determination of available residual prestress in in-service structures is necessary to assess the health of the structure and also to support rehabilitation measures, if required. The concrete core trepanning technique has been found to be useful for the determination of residual prestress in prestressed concrete structures. Experimental studies were carried out in the laboratory to establish the reliability of the technique. The core trepanning technique is simple to handle. Moreover this technique can be almost classified as a non-destructive technique since the structure can continue to be in service even after testing. Since the method of core trepanning has the possibility of introducing some minor errors, the estimation of residual prestress from only one (or) two cores is not advisable. Hence a statistical approach has to be made from a fairly large number of measurements to obtain the probable value with reasonable reliability rather than an exact value.

S. Parivallal

Papers

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

Experimental studies on fiber optic sensors embedded in concrete

Studies on Damage Detection Using Frequency Change Correlation Approach for Health Assessment

Non destructive evaluation of residual stresses in welded plates using the barkhausen noise technique

Technique to assess the residual prestress in prestressed concrete members