Tension Monitoring of Wedge Connection Using Piezoceramic Transducers and Wavelet Packet Analysis Method

Abstract

A steel strand is widely used in long span prestressed concrete bridges. The safety and stability of a steel strand are important issues during its operation period. A steel strand is usually subjected to various types of prestress loss which loosens the anchorage system, negatively impacting the stability of the structure and even leading to severe accidents. In this paper, the authors propose a wavelet packet analysis method to monitor the looseness of the wedge anchorage system by using stress wave-based active sensing. As a commonly used piezoceramic material, lead zirconate titanate (PZT) is employed with a strong piezoelectric effect. In the proposed active sensing approach, PZT patches are used as sensors and actuators to monitor the steel strand looseness. The anchorage system consists of the steel strand, wedges and barrel, which forms two different direct contact surfaces to monitor the tension force. PZT patches are pasted on the surface of each steel strand, corresponding wedge and barrel, respectively. Different combinations of PZTs are formed to monitor the anchoring state of the steel strand according to the position of the PZT patches. In this monitoring method of two contact surfaces, one PZT patch is used as an actuator to generate a stress wave and the other corresponding PZT patch is used as a sensor to detect the propagated waves through the wedge anchorage system. The function of these two PZTs were exchanged with the changing of transmission direction. The wavelet packet analysis method is utilized to analyze the transmitted signal between PZT patches through the steel strand anchorage system. Compared with the wavelet packet energy of received signals under different PZT combinations, it could be found that the wavelet packet energy increased with the increasing of anchorage system tightness. Therefore, the wavelet packet energy of received signal could be used to monitor the tightness of the steel strand during operation. Additionally, the wavelet packet energy of the received signals are different when the same PZT combination exchanges the energy transfer direction. With the comparison on the received signals of different combinations of PZTs, the optimal energy transfer path corresponding to different contact surfaces of the steel strand could be determined and the optimal experimental results are achieved.

A PZT-Based Smart Anchor Washer for Monitoring Prestressing Force Based on the Wavelet Packet Analysis Method

“…The conclusion shows th the tension increases, the index gradually decreases, indicating that the prestress sy is more stable. The tension force in this paper reached 18 tons, which far exceede 16,256 N tested by Zhang et al [46]. However, it should be noted that the inevitable i ference of surrounding environmental factors affected the resulting curve for each ten level, causing some degree of fluctuation.…”

“…Due to the high design value of bridge prestress, monitoring the entire range of bridge prestress is undoubtedly a significant challenge. Zhang et al [45,46] utilized the piezoceramic active sensing method, which is based on time reversal and the wavelet packet energy method, to monitor the prestress in the anchorage connection of the bridge.…”

Research on a Cognitive Distraction Recognition Model for Intelligent Driving Systems Based on Real Vehicle Experiments

“…Orthogonal wavelet basis functions are used in wavelet packet transformation and dyadic wavelet transformation. Both orthogonal and non-orthogonal wavelet foundation functions could be applied in continuous wavelet transformation [33]. In this work, the wavelet packet transform method was employed to deal with the data by employing the Haar wavelet, Daubechies wavelet, and Symlets wavelet, respectively.…”

Detecting of the Crack and Leakage in the Joint of Precast Concrete Segmental Bridge Using Piezoceramic Based Smart Aggregate

“…The WPEI defined by Equations (1)–(3) has been applied to signal processing in SHM of various structures, such as concrete structures [ 64 , 65 ], steel structures [ 66 , 67 ], composite structures [ 68 , 69 ] among others [ 70 , 71 ]. The received energy by SA can be calculated with WPEI in this experiment.…”