Health Monitoring of Prestressing Tendons in Posttensioned Concrete Bridges

Abstract

Currently 90% of bridges built in California are posttensioned box girder. In such structures, the steel tendons are the main load-carrying components. The loss of prestress, as well as the presence of defects or tendon breakage, can be catastrophic for the entire structure. No well-established method monitors prestressing tendons that can provide simultaneous information related to the presence of defects and the level of prestress in a continuous, real-time manner. If such a monitoring system were available, considerable savings would be achieved in bridge maintenance because repairs would be implemented in a timely manner without traffic disruptions. This paper presents a health-monitoring system for prestressing tendons in posttensioned structures of interest to the California Department of Transportation. Such a system uses guided ultrasonic waves and embedded sensors to measure the level of applied prestress and to detect defects at early growth stages simultaneously and in real time. The results of tests on a large-scale, single-tendon posttensioned joint specimen, subjected to multiple load cycles, are presented to validate the monitoring of prestress loads (through nonlinear ultrasonic probing) and the monitoring of damage progression and location (through acoustic emission techniques).

Corrosion Detection in PSC Bridge Tendons Using Kernel PCA Denoising of Measured MFL Signals

“…The guided ultrasonic wave is applied to the inspection of corrosion in pipelines and bridge tendons. This method uses vibrational characteristics of the ultrasonic wave and has been widely adopted to detect corrosion in pipelines [ 9 , 10 ]. However, it is reported that the wave experiences significant loss when penetrating concrete grouting, which causes difficulties in the measuring process [ 9 ].…”

Part Qualification Methodology for Composite Aircraft Components Using Acoustic Emission Monitoring

“…Provided that the appropriate sensing equipment and data-processing is applied, AE can provide real time volumetric information about dynamic changes related to damage. Based on this method, material damage processes at the coupon [17][18][19][20], component [21][22][23][24], and structural [25][26][27] scales have been reported. AE datasets can be further leveraged for advanced analytics such as data-driven models and machine learning [28][29][30][31][32], which may lead to a validated SHM methodology with potential even to be applied on-board, e.g., on aircraft [33].…”

Construction Condition and Damage Monitoring of Post-Tensioned PSC Girders Using Embedded Sensors

“…However, this approach is limited to being applied to bonded pre-stressing steel filled with grout. The guided wave passing through the concrete cannot be measured practically due to its attenuation in concrete [ 7 , 8 ]. As an alternative to overcome the drawbacks of ultrasonic and stress waves, a technique using a magnetic field was studied.…”