CN208805302U - A kind of concrete stress sensor - Google Patents

Abstract

The utility model discloses a kind of concrete stress sensors, belong to field of civil engineering.Concrete stress sensor is made of left end block, right end block and stress test column.Stress test column be special concrete, match ratio is identical as in concrete structure, only it is therein gather materials be replaced by it is ferromagnetic gather materials, two kinds of gradations gathered materials are identical.When stress test, external magnetic flux tester and the strain gauge constitute the magnetic circuit being closed and the stress in concrete can be obtained according to the induced voltage in induction coil after excitation coil generates pulsed magnetic field.The strain gauge is convenient for after engineering structure is built up, and concrete stress is detected, the influence that can be excluded automatically concrete shrinkage and creep, and simple structure, and low cost can reduce the testing cost of entire engineering structure with the engineering structure same service life, economical and practical.

Description

A kind of concrete stress sensor

Technical field

The utility model relates to a kind of concrete stress sensors, belong to field of civil engineering.

Background technique

Currently, common strain gauge can be roughly divided into following a few classes: (1) vibratory stress gauge in concrete structure External stress changes sensor string wire relaxation degree, so that sensor string wire is generated resonance by excitation chain, and reads string wire frequency Rate is to obtain stress value.(2) piezoelectric type strain gauge is using piezoelectric ceramics as sensing unit, by measurement piezoelectric material Equivalent circuit parameter reflects the static or quasi-static stress in concrete structure.(3) optical fiber optical grating stress sensor reflects The wavelength of light is very sensitive to stress and strain, and when elastomer is had pressure, fiber grating is answered together with elastomer Become, causes the peak wavelength of fiber grating reflected light to drift about, strain is sensed by the measurement to wavelength shift.

According to the working principle of the concrete stress sensor of the above routine it is found that current concrete stress test is all It is strained by measurement, considers further that the elasticity modulus of concrete obtained.Concrete material is after shaping, it may occur that drying shrinkage and Xu Become, it is therefore possible for the detected that concrete strain in comprising drying shrinkage and creep caused part so that the stress that we obtain and non-genuine Stress.In practical concrete works, people can only accurately test the strain increment that short-term laod or temporary load(ing) generate, from And obtain stress increment.To stress real-time in concrete, the test specimen of production, measurement drying shrinkage and the variation crept rule can only be utilized Rule calculates drying shrinkage and corresponding strain part of creeping in concrete, and the strain part is deducted in the overall strain of measurement, and then is calculated mixed Stress in solidifying soil.The stress mornitoring of concrete is always the problem of not being resolved in building industry in concrete structure, People thirst for directly measuring to obtain the real-time stress in concrete always.

Summary of the invention

Utility model aims to solve above-mentioned the deficiencies in the prior art and problems, provide a kind of coagulation Soil stress sensor.

A kind of concrete stress sensor provided by the utility model, the concrete stress sensor is by left end block, right end Block and the stress test column composition between left end block and right end block；The stress test column is special concrete, match ratio It is identical as the concrete in concrete structure, only it is therein gather materials be replaced by it is ferromagnetic gather materials, two kinds of gradations gathered materials are complete It is identical.The program is based primarily upon following principle: (1) drying shrinkage in concrete and creeping occurs mainly in cement slurry, with collection The relationship very little of material, therefore, the replacement of gathering materials does not influence the drying shrinkage of stress test column and creeps；(2) in concreting When, it is embedded to the concrete stress sensor that has just made, the cement slurry in concrete stress sensor suitably conserved, base at this time Not yet occur drying shrinkage and to creep in sheet, the drying shrinkage then occurred in the strain gauge and creeps and represent position concrete Drying shrinkage and creep, during subsequent loaded, the two deformation state is identical, and stress state is identical, the ferromagnetic stress to gather materials Represent the stress in the concrete of position；(3) cement slurry is not ferromagnetic material, and magnetic property is nearly constant constant, Ferromagnetic material has different magnetic conductivities in different stress states, and therefore, the ferromagnetic stress to gather materials determines the sensor Magnetic conduction ability；(4) using external magnetic flux tester when measuring, the magnetic field that excitation coil generates is sensed by concrete stress Two end blocks of device form a closed circuit, and the induction coil in magnetic flux tester is affected by magnetic fields, and can generate sense Answer voltage.Induced voltage is just related with the magnetic conduction ability of sensor, that is, related with the ferromagnetic stress to gather materials, and then and coagulation Stress in soil establishes corresponding relationship；(5) by laboratory test in advance, this corresponding relation curve can be established.Scene When test, according to obtained induced voltage, that is, the stress in concrete can determine.The concrete stress sensor is cheap, Increased engineering cost is also seldom, with the engineering structure same service life.

Further, left end block and right end block are same accessory, can be collectively referred to as end block, end block have one it is smooth passive Test surfaces, and separately have fluted in the middle part of a side.Which simplifies the design of end block and production, can be gradational to institute mixed Solidifying soil, only designs a kind of end block of specification.In the end insertion end block of stress test column, make left end block, stress test column and the right side End block three becomes fixed one, is convenient to be arranged to designated position after making, and with pouring for concrete, is embedded to coagulation In soil structure.

Further, ferromagnetic to gather materials using ferrite.This is because ferritic magnetic permeability is more much higher than common material.Cause And the sensitivity of strain gauge can be improved.

Further, two exposed Passive Test faces of the test structure are located at the same surface of engineering structure, and phase Concordantly；Exposed Passive Test face is smooth.When this is to guarantee external matched magnetic flux tester measurement, faying face can be close Patch.When making strain gauge, special auxiliary tool can be used and position corresponding two end blocks, it is ensured that its position is accurate.

The strain gauge is easy to make, and the concrete stress detection after building up convenient for engineering structure can exclude to mix automatically Solidifying soil drying shrinkage and the influence crept, obtain true real-time stress, simple structure, and low cost can be dropped with the engineering structure same service life The testing cost of low engineering structure, it is economical and practical.

Detailed description of the invention

The utility model diagram of Fig. 1 Transducers Embedded in Concrete.

Structural schematic diagram when Fig. 2 test stress.

The main body schematic diagram of Fig. 3 magnetic flux tester.

Fig. 4 utility model diagram.

Fig. 5 end block squints schematic diagram.

It is identified in figure: the left end 1- block;2- right end block;3- stress test column;4- concrete;5- groove;The left measurement arm of 6-;7- Right measurement arm;8- hand handle;9- active test surfaces;10- Passive Test face;The left excitation coil of 15-;The right excitation coil of 16-;17- sense Answer coil;19- concrete.

Specific embodiment

It is specific embodiment of the utility model below, and the technical solution of the utility model is retouched in conjunction with attached drawing It states, but the utility model is not limited to this embodiment.

Embodiment one

Base sheet stresses in the present embodiment setup test concrete box girder, concrete stress sensor schematic are shown in Fig. 1, figure 2 and Fig. 4, the concrete stress sensor are surveyed by left end block 1, right end block 2 and the stress between left end block 1 and right end block 2 Column 3 is tried to form；Stress test column 3 is special concrete, and shape is cylinder, diameter 100mm, length 200mm, match ratio and mixed Concrete 4 in Xtah Crude Clay structure is identical, only it is therein gather materials be replaced by ferrite, two kinds of gradations gathered materials are identical. Left end block 1 and right end block 2 are same accessory, can be collectively referred to as end block.End block with a thickness of 50mm, end block have one it is smooth passive Test surfaces 10, and separately have fluted 5 in the middle part of a side, it is specifically shown in Fig. 5.The diameter of groove 5 is 101mm, and depth 10mm is arrived The shortest distance in Passive Test face 10 is 30mm.The upper surface of end block is Passive Test face 10, lateral length 160mm.Stress After test pole 3 makes five hours, both ends of the surface are smeared with epoxy resin adhesive liquid, are installed into left end block 1 and the corresponding groove of right end block 2 In 5, and left end block 1 and 2 position of right end block are corresponding, their Passive Test face 10 is in the same plane.Pour underplate concrete Before 19, the strain gauge is placed and fixed, two exposed Passive Test faces 10 are in plate upper surface, and flush；It is exposed Passive Test face 10 it is smooth.Underplate concrete 19 is poured, after concrete 19 consolidates, that is, matched magnetic flux tester can be used to survey Try the stress of concrete 19.Matched magnetic flux tester is shown in Fig. 2, Fig. 3, by left measurement arm 6, right measurement arm 7 and 8 groups of hand handle At, there is left excitation coil 15 in left measurement arm 6, has right excitation coil 16 in right measurement arm 7, have induction coil 17 in hand handle 8, it should Magnetic flux transducer bilateral symmetry.When testing 19 stress of concrete, two active test surfaces 9 respectively with corresponding Passive Test Face 10 is opposite, and closely connected.

The description of above-mentioned specific embodiment is merely to illustrate the utility model, rather than the power of limitation the utility model Sharp protection scope.

Claims (6)

1. a kind of concrete stress sensor, it is characterised in that: the concrete stress sensor is by left end block, right end block and position Stress test column composition between left end block and right end block；The stress test column is made of special concrete, match ratio It is identical as the concrete in concrete structure, only it is therein gather materials be replaced by it is ferromagnetic gather materials, two kinds of gradations gathered materials are complete It is identical.

2. a kind of concrete stress sensor as described in claim 1, it is characterised in that: left end block and right end block are same Accessory can be collectively referred to as end block, and end block has a smooth Passive Test face, and separately has fluted in the middle part of a side.

3. a kind of concrete stress sensor as claimed in claim 2, it is characterised in that: ferromagnetic to gather materials using ferrite.

4. a kind of concrete stress sensor as claimed in claim 2, it is characterised in that: two exposed quilts of the test structure Dynamic test surfaces are on the same surface of engineering structure, and flush；Exposed Passive Test face is smooth.

5. a kind of concrete stress sensor as claimed in claim 2, it is characterised in that: the cross section of the groove is circle Shape, depth 10mm.

6. a kind of concrete stress sensor as claimed in claim 2, it is characterised in that: the cross section rectangle of the groove, Depth is 10mm.