Zapris Adamantis G, Naoum Maria C, Kytinou Violetta K, Sapidis George M, Chalioris Constantin E
Laboratory of Reinforced Concrete and Seismic Design of Structures, Civil Engineering Department, School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece.
Polymers (Basel). 2023 Jan 5;15(2):278. doi: 10.3390/polym15020278.
The favorable contribution of externally bonded fiber-reinforced polymer (EB-FRP) sheets to the shear strengthening of reinforced concrete (RC) beams is widely acknowledged. Nonetheless, the premature debonding of EB-FRP materials remains a limitation for widespread on-site application. Once debonding appears, it is highly likely that brittle failure will occur in the strengthened RC structural member; therefore, it is essential to be alerted of the debonding incident immediately and to intervene. This may not be always possible, particularly if the EB-FRP strengthened RC member is located in an inaccessible area for fast inspection, such as bridge piers. The ability to identify debonding immediately via remote control would contribute to the safer application of the technique by eliminating the negative outcomes of debonding. The current investigation involves the detection of EB-FRP sheet debonding using a remotely controlled electromechanical admittance (EMA)-based structural health monitoring (SHM) system that utilizes piezoelectric lead zirconate titanate (PZT) sensors. An experimental investigation on RC T-beams strengthened for shear with EB-FRP sheets has been performed. The PZT sensors are installed at various locations on the surface of the EB-FRP sheets to evaluate the SHM system's ability to detect debonding. Additionally, strain gauges were attached on the surface of the EB-FRP sheets near the PZT sensors to monitor the deformation of the FRP and draw useful conclusions through comparison of the results to the wave-based data provided by the PZT sensors. The experimental results indicate that although EB-FRP sheets increase the shear resistance of the RC T-beams, premature failure occurs due to sheet debonding. The applied SHM system can sufficiently identify the debonding in real-time and appears to be feasible for on-site applications.
外部粘贴纤维增强聚合物（EB - FRP）板对钢筋混凝土（RC）梁抗剪加固的有利作用已得到广泛认可。尽管如此，EB - FRP材料的过早脱粘仍然是其在现场广泛应用的一个限制因素。一旦出现脱粘，加固后的RC结构构件很可能会发生脆性破坏；因此，必须立即察觉到脱粘事件并进行干预。但这并非总是可行的，特别是当EB - FRP加固的RC构件位于难以快速检查的区域时，例如桥墩。通过远程控制立即识别脱粘的能力将有助于消除脱粘的负面后果，从而更安全地应用该技术。当前的研究涉及使用基于远程控制的机电导纳（EMA）的结构健康监测（SHM）系统来检测EB - FRP板的脱粘，该系统利用压电锆钛酸铅（PZT）传感器。对用EB - FRP板进行抗剪加固的RC T梁进行了试验研究。PZT传感器安装在EB - FRP板表面的不同位置，以评估SHM系统检测脱粘的能力。此外，在靠近PZT传感器的EB - FRP板表面粘贴应变片，以监测FRP的变形，并通过将结果与PZT传感器提供的基于波的数据进行比较得出有用的结论。实验结果表明，尽管EB - FRP板提高了RC T梁的抗剪能力，但由于板的脱粘会发生过早破坏。所应用的SHM系统能够充分实时识别脱粘情况，并且对于现场应用似乎是可行的。
