Nde of Tendon Ducts in Concrete Using 3D-Saft

1997 ◽  
Vol 503 ◽  
Author(s):  
M. Krause ◽  
H. Wiggenhauser ◽  
W. Müller ◽  
V. Schmitz
Keyword(s):  
Data Analysis ◽  
Ultrasonic Testing ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Laser Doppler Vibrometer ◽  
Laser Doppler ◽  
Impact Echo ◽  
Concrete Members ◽  
Testing Techniques ◽  
Post Tensioned

ABSTRACTPrestressed or post-tensioned concrete structures are vulnerable to hazardous corrosion, if the tendon ducts are not fully injected with grout. Also compaction faults reduce the concrete strength. Advanced ultrasonic testing techniques and data analysis have been utilized to evaluate ducts in concrete members nondestructively. A laser Doppler vibrometer is used as an ultrasonic receiver to automatically collect the data. With this method ducts could be investigated which are not accessible by other methods as radiography or impact-echo. Encouraging results on different specimens are presented.

Impact-Echo Based Nondestructive Evaluation of Grout Condition in Post-Tensioned Bridge Ducts

2010 ◽  
Vol 168-170 ◽  
pp. 1122-1125
Author(s):  
Zhi Feng Wang ◽  
Xian Yan Zhou
Keyword(s):  
Quality Control ◽  
Cost Effectiveness ◽  
Nondestructive Evaluation ◽  
Civil Engineering ◽  
Critical Role ◽  
Concrete Structures ◽  
Impact Echo ◽  
Interdisciplinary Field ◽  
Post Tensioned

The field of Nondestructive Evaluation (NDE) is a very broad, interdisciplinary field that plays a critical role in civil engineering for controlling new structures (quality control) as well as for assessing the internal grout condition of prestressed pipes in post-tensioned concrete structures. Because it allows voids in grouted tendon ducts to be inspected and measured without damaging them, impact-echo based NDE provides an excellent balance between quality control and cost-effectiveness. This paper focuses on the nondestructive evaluation of internal injection quality in post-tensioned bridge ducts, and the developments in civil engineering NDE in China are also introduced.

scholarly journals Influence of axial loads on the health monitoring of concrete structures using embedded piezoelectric transducers

2016 ◽  
Vol 16 (2) ◽  
pp. 202-214 ◽  
Author(s):  
Tiejun Liu ◽  
Dujian Zou ◽  
Chengcheng Du ◽  
Ying Wang
Keyword(s):  
Health Monitoring ◽  
Axial Load ◽  
Concrete Strength ◽  
Compressive Loading ◽  
Concrete Structures ◽  
Potential Method ◽  
Concrete Members ◽  
Stress Levels ◽  
High Frequency Waves ◽  
Stress Dependent

Piezoceramic-based smart aggregate has been widely used to evaluate early-age concrete strength and to detect damage in concrete structures. In these structural health monitoring systems, they are generally verified and calibrated through experiments under load-free condition. However, the stress levels of actual concrete members are different. The microstructures of concrete will change with the variation of external load, and the high-frequency waves used in the monitoring system may be highly sensitive to these changes. In this study, the effects of axial compressive loading on the monitoring results are investigated. Specifically, three loading cases, that is, single cycle load, cyclic load, and step-by-step load, are employed to stress the concrete specimens embedded with smart aggregates. The amplitude and velocity of monitoring signals were measured before, during, and after each loading case. The test results show that the axial load lower than 30% of failure load still have a significant impact on the received signals. The amplitude attenuation is dependent on both frequency and load history, while the velocity is highly stress-dependent. The results indicate that the baselines of monitoring signals obtained from the same concrete structure in its healthy state can vary under different stress levels. The axial load variation should be carefully considered during the monitoring process. This study also provides a potential method to assess stress state in concrete structures using smart aggregates.

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