An Experimental Investigation on Flexural Behavior of Reinforced Concrete Beams Strengthened by an Intelligent CFRP Plate with Built-In Optical Fiber Bragg Grating Sensors

Abstract

The difficulties induced from high-durability package, large-scale measurement, and sensor installation make it a big challenge but an urgent need to predict the mechanical behavior of strengthened reinforced concrete structure with the externally bonded fiber-reinforced polymer (FRP) plate under harsh environments and rough construction process. In an effort to solve this challenge, this paper proposes a novel end anchored self-sensing CFRP plate assembly with built-in optical fiber Bragg grating (FBG) sensor. The self-sensing principle is presented and a demonstration test was carried out in the laboratory in order to investigate the self-sensing properties of the intelligent CFRP plate. Three-point flexural tests of a total of ten RC beams were carried on: six strengthened with the bonded or unbonded posttensioned intelligent CFRP plates, one strengthened with the ordinary CFRP plate, and three strengthened with the control beams. The full-range CFRP plate strain at the maximum moment was measured utilizing the FBG interrogator. Using this monitoring data, the short-term prestress loss attributed to anchorage set and the relationship between the external load and the CFRP strain at the middle span associated with the integral response of the strengthened member were investigated. Besides, the objective of the tests was also to gain a better understanding of the failure mode and the flexural behavior of RC beams strengthened with posttensioned CFRP plates taking into account the different strengthening methods, initial damage, and the dead load before strengthening. The experimental results showed that the developed CFRP plate with built-in FBG sensors not only can be the reinforcement of the RC structures, but also provide an effective way to monitor the full-range behavior of the CFRP plate with the excellent self-sensing property shown in the demonstration tests.

Research Progress in Environmental Response of Fiber Concrete and Its Functional Mechanisms

“…When the broadband light transmits through optical fiber, the light will pass through at a smaller attenuation. In contrast, the narrowband light is transmitted through optical fiber, reflecting in the Prague grating portion [74]. Prague wavelength is shown as follows:…”

Experimental Investigation of BFRP Tendons under Monotonic and Hysteretic Loadings

“…However, the behaviors of the BFRP tendons with greater diameters and their anchor performances under a high loading rate also need attention. Therefore, to fully develop the advantages of BFRP, especially for self-centering applications [16,24], the monotonic and hysteretic behaviors of the BFRP tendons should be tested and predicted, considering the anchor colloid deformation.…”

Experimental study on the mechanical and self-sensing behaviors of prestressed carbon fiber–reinforced polymer reinforced concrete composite structures

“…The other reason is the implausibility of employing ''point'' sensors over all potential damage areas of large-scale structures due to cost control. With the development of sensing technology, several new measures have been developed, such as the application of fiber Bragg grating (FBG) sensors (Hong et al, 2012;Li and Wu, 2007;Zhou and Wang, 2018). Furthermore, the FBG sensor can be attached on the concrete surface, FRP or steel rebar, and the interface between FRP and RC structure to monitor the performances of the structure (Kesavan et al, 2013).…”