Monitoring of Corrosion in Structural Reinforcing Bars: Performance Comparison Using In Situ Fiber-Optic and Electric Wire Strain Gauge Systems

Abstract

This work addresses the problems of effective in situ measurement of the initiation or the rate of steel corrosion in reinforced concrete structures through the use of optical fiber sensor systems. By undertaking a series of tests over prolonged periods, coupled with acceleration of corrosion, the performance of fiber Bragg grating-based sensor systems attached to high-tensile steel reinforcement bars ("rebars"), and cast into concrete blocks was determined, and the results compared with those from conventional strain gauges where appropriate. The results show the benefits in the use of optical fiber networks under these circumstances and their ability to deliver data when conventional sensors failed.

Development of a Bridge Weigh-in-Motion Sensor: Performance Comparison Using Fiber Optic and Electric Resistance Strain Sensor Systems

“…The value of λ B used is in the region around ~ 1550 nm. FBGs are written into Boron-Germanium doped optical fibre which is recoated to restore the original mechanical strength of the fibre [14], [15]For FBG-based B-WIM sensors for monitoring the localised strain several different packaging and amplifying systems together with fixing techniques were investigated. The optical sensors can be multiplexed along very long lengths of fibre, are well suited to large structures and can be set accurately by placing the FBGs at pre-determined points along a configured optical sensor network.…”

Fiber Bragg Grating-Based System for 2-D Analysis of Vibrational Modes of a Steel Propeller Blade

“…Therefore integrating the above formula twice will provide a relationship for the deflection at each FBG location for the various modal shapes. A zero displacement boundary condition was considered at the clamped end of the plate and in order to solve the 4th or 5th degree polynomial functions of deflection and to find the nodal position, Roark's formula for a cantilevered beam was used [17] √ (3) where is the natural frequency (Hz), is a constant where refers to the mode of vibration, is gravitational acceleration (units consistent with length dimension), is the modulus of elasticity and is area moment of inertia. and are uniform load per unit length (including beam weight) and beam length respectively.…”

Method for producing angled optical fiber tips in the laboratory

“…In recent years, optical fibers have become an extremely valuable industrial technology, most notably in telecommunications and also in sensors [1][2][3][4] and a range of medical applications. [5][6][7] Specifically for sensors, fibers have the advantage of being small in size and flexible, allowing them to reach remote locations.…”