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Experimental estimating deflection of a simple beam bridge model using grating eddy current sensors.

Lü C, Liu W, Zhang Y, Zhao H - Sensors (Basel) (2012)

Bottom Line: Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints.In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection.Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches.

View Article: PubMed Central - PubMed

Affiliation: Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. chunfenglv@sjtu.edu.cn

ABSTRACT
A novel three-point method using a grating eddy current absolute position sensor (GECS) for bridge deflection estimation is proposed in this paper. Real spatial positions of the measuring points along the span axis are directly used as relative reference points of each other rather than using any other auxiliary static reference points for measuring devices in a conventional method. Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints. In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection. Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches. Principles of the three-point method and displacement measurement of the GECS are introduced in detail. Both static and dynamic experiments have been carried out on a simple beam bridge model, which demonstrate that the three-point deflection estimation method using the GECS is effective and offers a reliable way for bridge deflection estimation, especially for long-term monitoring.

No MeSH data available.


Related in: MedlinePlus

Instrumentation plan of a simple beam.
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f2-sensors-12-09987: Instrumentation plan of a simple beam.

Mentions: Due to the mid-measuring point in one measuring unit is used for installation of the GECS and meanwhile, it is the endpoint of the previous or next measuring unit used for connecting bar installation, which makes choice of the measuring points and connecting bars installation should be along two lines paralleled to the span axis, respectively. A complete instrumentation plan is shown in Figure 2. An individual bar is used for each measuring unit. In order to remain the connecting bar straight after the beam is loaded, the bars are free to rotate at the one end and pin-connected at the other end. A free space is reserved at the pin-connected section of the connecting bar, and it can also remove the effect of differentiate thermal deformations when the reference bar and the bridge use different materials. The beam is divided into n − 1 continuous measuring units, of which the relative deflection zi (i = 1, 2, …, n − 2, n − 1) can be obtained simultaneously while a flexural deflection happens.


Experimental estimating deflection of a simple beam bridge model using grating eddy current sensors.

Lü C, Liu W, Zhang Y, Zhao H - Sensors (Basel) (2012)

Instrumentation plan of a simple beam.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472811&req=5

f2-sensors-12-09987: Instrumentation plan of a simple beam.
Mentions: Due to the mid-measuring point in one measuring unit is used for installation of the GECS and meanwhile, it is the endpoint of the previous or next measuring unit used for connecting bar installation, which makes choice of the measuring points and connecting bars installation should be along two lines paralleled to the span axis, respectively. A complete instrumentation plan is shown in Figure 2. An individual bar is used for each measuring unit. In order to remain the connecting bar straight after the beam is loaded, the bars are free to rotate at the one end and pin-connected at the other end. A free space is reserved at the pin-connected section of the connecting bar, and it can also remove the effect of differentiate thermal deformations when the reference bar and the bridge use different materials. The beam is divided into n − 1 continuous measuring units, of which the relative deflection zi (i = 1, 2, …, n − 2, n − 1) can be obtained simultaneously while a flexural deflection happens.

Bottom Line: Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints.In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection.Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches.

View Article: PubMed Central - PubMed

Affiliation: Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. chunfenglv@sjtu.edu.cn

ABSTRACT
A novel three-point method using a grating eddy current absolute position sensor (GECS) for bridge deflection estimation is proposed in this paper. Real spatial positions of the measuring points along the span axis are directly used as relative reference points of each other rather than using any other auxiliary static reference points for measuring devices in a conventional method. Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints. In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection. Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches. Principles of the three-point method and displacement measurement of the GECS are introduced in detail. Both static and dynamic experiments have been carried out on a simple beam bridge model, which demonstrate that the three-point deflection estimation method using the GECS is effective and offers a reliable way for bridge deflection estimation, especially for long-term monitoring.

No MeSH data available.


Related in: MedlinePlus