Self-sensing and strengthening effects of reinforced concrete structures with near-surfaced mounted smart basalt fibre–reinforced polymer bars

Abstract

A new retrofitting system is proposed for reinforced concrete structures with application of near-surfaced mounted smart basalt fibre-reinforced polymer bar. The distributed optical fibre sensing technology, namely pre-pump pulse Brillouin optical time-domain analysis, is applied as the sensing technology for the smart bar. Then the proposed system is explained in detail from both self-sensing and strengthening. Finally, some experiments were implemented with reinforced concrete beams to verify the actual effects. From the results, it is concluded that the ultimate strength and the stiffness after steel rebar yielding can be increased obviously due to the high strength and ultimate strain of the smart basalt fibre-reinforced polymer bar. Meanwhile, the structure strain distribution can be measured with the smart basalt fibre-reinforced polymer bar, with which some key parameters can be well assessed, such as crack location, crack width, displacement and bending moment. However, the self-sensing effects indeed have been obviously influenced by the strain measurement accuracy especially after concrete cracking. Therefore, it is meaningful to improve the sensing accuracy especially for complicated strain. Additionally, some prestress upon the smart basalt fibre-reinforced polymer bar can improve both sensing and strengthening performance.

Dynamic displacement monitoring of flexural structures with distributed long-gage macro-strain sensors

“…The standard deviation between the strain gage and FBG was approximately 12 me, whereas it was only 3 me between the two FBG sensor types. The dynamic displacement was obtained using the measured distributed strain in equation (3). Therefore, the displacement-time history from nodes N 0 to N 5 was easily obtained.…”

“…Structural health monitoring (SHM) was proposed and applied as a solution to ensure structural safety. [1][2][3] Displacement is a key parameter in the design process of flexural structures such as classical girder bridges and is usually required for monitoring with SHM. Due to dynamic effects, the dynamic displacement is of greater importance in evaluating structural performance than the static displacement.…”

An innovative geotechnical and structural monitoring system based on the use of NSHT

“…Optical cables directly connected with structures or with inner iron reinforcement, in tunnels and single structural elements such as concrete pillars and beams, have been tested in order to realize smart structures that allow continuous monitoring [28][29][30]. In other studies, reinforcement interventions with smart composite bars are proposed [31][32][33][34]: the bars are equipped with optical cables so that the structural reinforcement elements represent the sensors themselves. Monitoring with smart bars, however, allows acquiring information about the reinforcement intervention itself rather than on the health of the overall structure.…”

Smart self-sensing fiber-reinforced polymer sheet with woven carbon fiber line sensor for structural health monitoring

“…A smart self-sensing basalt FRP bar for retrofitting reinforced concrete structures with a near-surfaced mounted application, utilizing distributed optical fiber sensing technology, was proposed by Tang et al (2016). From the strain distribution obtained, the location of main cracks, crack width, and the displacement are well assessed; however, further research should be implemented to increase the strain measurement accuracy of the smart basalt FRP bar.…”