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Twisted steel prestress detection device and method based on magnetic flux test

A threaded steel bar and detection method technology, which is applied in the direction of measurement device, measurement of the change force of material magnetic properties caused by applied stress, measurement of force, etc., can solve the problems of poor applicability, cumbersome operation, and large error of test results, etc. problems, to achieve the effect of wide application range, high test accuracy and low equipment maintenance cost

Active Publication Date: 2020-12-18
SHANDONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the problems of large test result error, cumbersome operation and poor applicability in the above-mentioned threaded steel prestress detection technology, the present invention proposes a detection device and method for the effective prestress of threaded steel bars based on magnetic flux testing, through non-contact magnetic flux The sensor magnetizes the prestressed tendon, calibrates the potential change caused by the tension of the internal threaded steel bar in the magnetic field environment, and calculates the effective prestressed value based on the relationship model between the length of the exposed section of the threaded steel bar, the test potential difference of the magnetic flux before and after tensioning, and the prestress under the anchor

Method used

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  • Twisted steel prestress detection device and method based on magnetic flux test
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  • Twisted steel prestress detection device and method based on magnetic flux test

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Embodiment 1

[0029] The effective prestress detection device for threaded steel bars based on the magnetic flux test proposed in this embodiment, such as figure 1 , figure 2 Shown, comprise magnetic flux sensor 4, pressure sensor 6, top surface steel backing plate 7, bottom surface steel backing plate 5; The bottom surface is provided with a bottom steel backing plate 5; the top steel backing plate 7, the bottom steel backing plate 5 and the contact surface of the pressure sensor are completely attached, and the contact surface between the three is kept vertical to the threaded steel bar; the top steel backing plate 7 The top of the magnetic flux sensor is provided with a magnetic flux sensor. The magnetic flux sensor is a cavity structure, and the nut matched with the threaded steel bar can be completely put into the sensor without touching the inner wall of the sensor. The height of the magnetic flux sensor is greater than the height of the nut; the magnetic flux sensor and the magnetic...

Embodiment 2

[0033] Based on embodiment 1, this implementation proposes a detection method, comprising the following steps:

[0034] The specific steps of step 1 are:

[0035] Such as figure 1 As shown, a magnetic flux testing system equipment suitable for threaded steel bar prestress detection is designed, and the inner diameter of the inner cavity of the magnetic flux sensor 4 is designed according to the diagonal distance of the hexagonal section to ensure that the nut 3 can be completely placed in the sensor 4 without contact inner wall of the sensor. The height of the magnetic flux sensor 4 is greater than that of the nut 3, so as to ensure that the entire nut 3 and the threaded steel bar 2 are in the magnetic induction environment.

[0036] The concrete steps of described step 2 are:

[0037] Such as figure 1 , figure 2 As shown, the prestressed concrete beam 1 in the actual project site is subjected to graded tensioning of the threaded steel bar prestressing, and the prestress...

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Abstract

The invention provides a twisted steel prestress detection device and method based on a magnetic flux test. A magnetic flux sensor is arranged outside a twisted steel and an anchoring nut in a sleeving mode, the twisted steel and the nut in a magnetic field environment are magnetized, the twisted steel generates tiny strain after being tensioned and stressed, and the potential in the sensor changes, a three-parameter relation model of anchoring tension, the length of the exposed section of the twisted steel and the induced potential difference is obtained through grading tension calibration ofthe twisted steel in actual engineering. The method is characterized in that the detection process is convenient and fast, the initial induced potential only needs to be tested before tensioning, theexposed length and the induced potential of the twisted steel are tested after tensioning is completed, and the under-anchor effective prestress of the twisted steel can be calculated on the basis ofa relation model of the under-anchor tensioning force, the exposed length of the twisted steel and the induced potential difference. The detection method belongs to a nondestructive testing technology, and has the advantages of high detection result precision, small influence of on-site construction environment, wide application range and the like.

Description

technical field [0001] The invention relates to the technical field of bridge prestress detection, in particular to a detection device and method for effective prestress of bridge threaded steel bars using magnetic flux testing. Background technique [0002] Because of its simple structure and convenient construction and operation, high-strength threaded steel bars are often used as prestressed tendons in prestressed concrete bridge structures and widely used in box girder webs. However, in the prestressed tensioning construction of threaded steel bars, since most of the tensioning and anchoring process is performed by construction personnel manually tightening the anchor nuts, the degree of tightness and installation accuracy between the nuts and threaded steel bars cannot achieve a uniform standard, so effective pre-stressing If the stress loss is not accurately controlled, it is easy to cause the prestress of the bridge to fail to meet the design requirements or even fail...

Claims

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Application Information

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IPC IPC(8): G01L1/12
CPCG01L1/127
Inventor 张峰张心纯任文辉高磊马彦阳高华睿张秀峰邓建波高祥
Owner SHANDONG UNIV