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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

Laboratory simply beam bridge model: (a) deflection estimation system. (b) the GECS: A, B and C are the measuring board, reflective conductors and connecting bar.
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f5-sensors-12-09987: Laboratory simply beam bridge model: (a) deflection estimation system. (b) the GECS: A, B and C are the measuring board, reflective conductors and connecting bar.

Mentions: A laboratory simply bridge model is shown in Figure 5. The beam is 1,280 mm long, on which the choice of the equidistant measuring points and connecting bar installation are accomplished along two lines paralleling to the span axis respectively according to Figure 2. For this model, measuring points are chosen every 320 mm along the span axis, thus five measuring points including the two endpoints are selected. The whole deflection estimation system is divided into three measuring units, and in each unit, the connecting bar is 640 mm long. Three dial gauges are used for direct reading out the absolute deflections of measuring points 1, 2 and 3, and meanwhile, a laser displacement meter (LDM) under the beam is used for recording real-time deflection of measuring point 2. For verification of the three-point method, both static and dynamic experiments have been carried out on this model.


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)

Laboratory simply beam bridge model: (a) deflection estimation system. (b) the GECS: A, B and C are the measuring board, reflective conductors and connecting bar.
© Copyright Policy
Related In: Results  -  Collection

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

f5-sensors-12-09987: Laboratory simply beam bridge model: (a) deflection estimation system. (b) the GECS: A, B and C are the measuring board, reflective conductors and connecting bar.
Mentions: A laboratory simply bridge model is shown in Figure 5. The beam is 1,280 mm long, on which the choice of the equidistant measuring points and connecting bar installation are accomplished along two lines paralleling to the span axis respectively according to Figure 2. For this model, measuring points are chosen every 320 mm along the span axis, thus five measuring points including the two endpoints are selected. The whole deflection estimation system is divided into three measuring units, and in each unit, the connecting bar is 640 mm long. Three dial gauges are used for direct reading out the absolute deflections of measuring points 1, 2 and 3, and meanwhile, a laser displacement meter (LDM) under the beam is used for recording real-time deflection of measuring point 2. For verification of the three-point method, both static and dynamic experiments have been carried out on this model.

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