Feasibility Study of Stress Measurement in Prestressing Tendons Using Villari Effect and Induced Magnetic Field

Joh, Changbin; Lee, Jung Woo; Kwahk, Imjong

doi:10.1155/2013/249829

Cited by 19 publications

(13 citation statements)

References 15 publications

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“…Duan et al [6][7][8][9][10][11], based on magnetoelastic effect, has carried out an experimental study on stress monitoring of the high-strength steel wire, reinforced bar, and prestressed steel strands. Based on this method, Joh et al [12] conducted a feasibility study on noncontact stress detection of steel strands. Kim et al [13] proposed a tension monitoring system of a prestressed beam based on an embedded electromagnetic sensor.…”

Section: Introductionmentioning

confidence: 99%

Study on the Main Factors of Frequency Variation of LC Resonant Prestress Detection Method

Zhang

Zhao

et al. 2020

Advances in Materials Science and Engineering

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Stress loss of prestressed steel strands of existing bridges influences their bearing capacity, so it is of great significance to realize the stress detection. A steel strand that has an inductive property is designed into the resonant circuit, which can realize the stress measurement of the steel strands by testing the resonant frequency. This method is a promising approach for the stress detection of the steel strands. Previous research found that structural stress made the permeability of steel strands change due to the influence of magnetoelastic effect. In the process, the length of steel strands is also changed. Therefore, further research needs to be done to verify the main influence parameter affecting the resonant frequency of the circuit. Furthermore, it is very important to know how the stress affects the resonant frequency to realize the detection of the prestressed force of the steel strands. Therefore, in this paper, the relationship between stress and relative permeability and length is analyzed theoretically, and the theory of stress frequency of steel strands is modified and verified by experiments. The stress-frequency experiments of steel strands and aluminum strands with great difference in relative permeability are carried out. Experiments on stress frequencies of 7-Ф15.20 mm steel strands with different lengths are carried out. The influence of length and permeability parameters on resonance frequency is analyzed. The experimental results show that under the same conditions, the resonant frequencies of steel strands and aluminum strands are almost the same on LC electric circuits, and the resonant frequency decreases linearly with the increase of the natural length of the component and increases linearly with the increase of stress. Consequently, compared with the influence of length change on LC electromagnetic resonance frequency, the relative permeability of the stress change component can be ignored. The stress changes the resonant frequency mainly by changing the length of the strands.

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Section: Introductionmentioning

confidence: 99%

Study on the Main Factors of Frequency Variation of LC Resonant Prestress Detection Method

Zhang

Zhao

et al. 2020

Advances in Materials Science and Engineering

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“…Ultrasonic guided wave detection in cable and anchorage systems must be strictly demarcated, however the steel strand itself has clearance and may have original defects at the beginning, so the results are not ideal [ 11 , 12 ]. Due to the complexly ferromagnetic environment around the steel strand, the anti-ferromagnetic ability should be determined [ 13 , 14 ]. Prestressing force gauge prestressed at the external anchor head can effectively monitor the change of working stress of prestressed steel strand.…”

Section: Introductionmentioning

confidence: 99%

Prestress Monitoring of a Steel Strand in an Anchorage Connection Using Piezoceramic Transducers and Time Reversal Method

Zhang

Liu

et al. 2018

Sensors

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Steel strands are widely used in cable stay or suspension bridges. The safety and stability of steel strands are important issues during their operation period. Steel strand is subjected to various types of prestress loss which loosens the wedge anchorage system, negatively impacting the stability of the structure and even leading to severe accidents. In this paper, the authors propose a time reversal (TR) method to monitor the looseness status of the wedge anchorage system by using stress wave based active sensing. As a commonly used piezoceramic material, Lead Zirconate Titanate (PZT) with a strong piezoelectric effect is employed. In the proposed active sensing approach, PZT patches are used as sensors and actuators to monitor the steel strand looseness status. One PZT patch is bonded to the steel strand, one PZT patch is bonded to the wedges, and another PZT patch is bonded to the barrel. There are three different interfaces of the wedge anchorage system to monitor the steel strand looseness status. In the first method, the PZT patch on the steel strand is used as an actuator to generate a stress wave and the PZT patch on the wedge is used as a sensor to detect the propagated waves through the wedge anchorage system. In the second method, the PZT patch on the steel strand is used as an actuator to generate a stress wave and the PZT patch on the barrel is used as a sensor to detect the propagated waves through the wedge anchorage system. In the third method, the PZT patch on the wedges is used as an actuator to generate a stress wave and the PZT patches on the barrel is used as a sensor to detect the propagated waves through the wedge anchorage system, of which the looseness will directly impact the stress wave propagation. The TR method is utilized to analyze the transmitted signal between PZT patches through the wedge anchorage system. Compared with the peak values of the TR focused signals, it can be found that the peak value increases as the wedge anchorage system tightness increases. Therefore, the peak value of the TR focused signal can be used to monitor the tightness of the steel strand. In addition, the experimental results demonstrated the time reversal method’s reliability, sensitivity and anti-noise property.

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“…It can measure the permeability to estimate the stress and it has been used to monitor the stress in exposed steel cables on field more than ten years [ 24 , 25 , 26 ]. The many types of EM sensors were invested using coil type [ 27 ], yoke-shaped electromagnet with hall sensors [ 28 ], and coil type electromagnet with magneto-electric-laminated composite sensor [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

Development of Embedded EM Sensors for Estimating Tensile Forces of PSC Girder Bridges

Kim¹,

Kim

Lee³

et al. 2017

Sensors

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The tensile force of pre-stressed concrete (PSC) girders is the most important factor for managing the stability of PSC bridges. The tensile force is induced using pre-stressing (PS) tendons of a PSC girder. Because the PS tendons are located inside of the PSC girder, the tensile force cannot be measured after construction using conventional NDT (non-destructive testing) methods. To monitor the induced tensile force of a PSC girder, an embedded EM (elasto-magnetic) sensor was proposed in this study. The PS tendons are made of carbon steel, a ferromagnetic material. The magnetic properties of the ferromagnetic specimen are changed according to the induced magnetic field, temperature, and induced stress. Thus, the tensile force of PS tendons can be estimated by measuring their magnetic properties. The EM sensor can measure the magnetic properties of ferromagnetic materials in the form of a B (magnetic density)-H (magnetic force) loop. To measure the B-H loop of a PS tendon in a PSC girder, the EM sensor should be embedded into the PSC girder. The proposed embedded EM sensor can be embedded into a PSC girder as a sheath joint by designing screw threads to connect with the sheath. To confirm the proposed embedded EM sensors, the experimental study was performed using a down-scaled PSC girder model. Two specimens were constructed with embedded EM sensors, and three sensors were installed in each specimen. The embedded EM sensor could measure the B-H loop of PS tendons even if it was located inside concrete, and the area of the B-H loop was proportionally decreased according to the increase in tensile force. According to the results, the proposed method can be used to estimate the tensile force of unrevealed PS tendons.

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Feasibility Study of Stress Measurement in Prestressing Tendons Using Villari Effect and Induced Magnetic Field

Cited by 19 publications

References 15 publications

Study on the Main Factors of Frequency Variation of LC Resonant Prestress Detection Method

Study on the Main Factors of Frequency Variation of LC Resonant Prestress Detection Method

Prestress Monitoring of a Steel Strand in an Anchorage Connection Using Piezoceramic Transducers and Time Reversal Method

Development of Embedded EM Sensors for Estimating Tensile Forces of PSC Girder Bridges

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