RC梁钢筋锈蚀监测与概率成像定位

为评估RC结构内钢筋的锈蚀损伤状态，开展了基于压电传感的RC梁钢筋锈蚀监测与定位技术研究。首先，在钢筋表面布设3组压电陶瓷（PZT）传感器，随后对监控到的信号进行基4FFT变换和提取频谱特征，刻画了钢筋锈蚀发展过程，并验证了基于PZT的监控方法对钢筋锈蚀全过程监测的适用性；其次，通过对概率成像方法中的权重函数进行修正，得到锈蚀位置图像，进而对钢筋的锈蚀位置进行定位分析；最后，通过频域信号峰值分析，建立损伤因子与锈蚀率的定量关系来量化钢筋的锈蚀程度。结果表明：RC梁中钢筋的锈蚀过程可分为脱钝、脱黏和失效3个阶段；提出的损伤因子F_DI可有效刻画钢筋锈蚀过程中的3个阶段，并量化钢筋锈蚀率；新的概率成像方法实现了钢筋锈蚀的全过程监测和锈蚀损伤的定位分析。这表明本文研发的监测技术与概率成像方法可以精准地监控RC结构中钢筋锈蚀全过程与锈蚀位置，建立的锈蚀各阶段与损伤因子的定量关系可用来量化钢筋锈蚀程度，并为RC结构安全评估提供技术支持。

Corrosion monitoring and probabilistic imaging location of steel bars in RC beams

To further evaluate the corrosion conditions of steel bars in RC structures, the monitoring and location technology for the corroded steel bars in RC beams was investigated based on piezoelectric sensors. Firstly, three pairs of piezoelectric lead zirconate titanate (PZT) sensors were arranged on the surface of the steel bar, then the monitored signals were processed by Radix-4 FFT, and the frequency spectrum features were extracted to figure out the development trend of the corrosion process. Meanwhile, the applicability of the PZT-based monitoring method for the overall corrosion process of steel bars was verified. Secondly, for the purpose of locating the corrosion positions of the steel bar, the weight function of the probabilistic imaging method was modified to obtain the position image of the corroded steel bar. Finally, the peak signal in the frequency domain was analyzed, and the relationship between the damage factor (F_DI) and the corrosion rate was established to quantify the corrosion degree of the steel bar. Results show that the corrosion process of steel bars in RC beams could be divided into three phases: depassivation phase, debonding phase, and failure phase; the proposed damage factor (F_DI) could effectively depict the three phases in the corrosion process of steel bars and quantify the corrosion rate of steel bars; the probabilistic imaging method could realize whole-process monitoring and analyze the corrosion positions of the steel bars. It indicates that the monitoring technology and the probabilistic imaging method can accurately monitor the overall process and locate the corrosion positions of steel bars in RC structures. The relationship between each phase of the whole process and the damage factor (F_DI) can quantify the steel corrosion rate, which can provide technical support for the safety assessment of RC structures.